Left, Smith Richards, grocer and confectioner, "at the sign of the tea

canister and two sugar loaves" (1773); center, the King's Arms,

originally Burns coffee house (1767); right, George Webster, Grocer, "at

the sign of the three sugar loaves"]

CHAPTER XIV

COFFEE HOUSES OF OLD PHILADELPHIA

_Ye Coffee House, Philadelphia's first coffee house, opened about

1700--The two London coffee houses--The City tavern, or Merchants

coffee house--How these, and other celebrated resorts, dominated

the social, political, and business life of the Quaker City in the

eighteenth century_

William Penn is generally credited with the introduction of coffee into

the Quaker colony which he founded on the Delaware in 1682. He also

brought to the "city of brotherly love" that other great drink of human

brotherhood, tea. At first (1700), "like tea, coffee was only a drink

for the well-to-do, except in sips."[93] As was the case in the other

English colonies, coffee languished for a time while tea rose in favor,

more especially in the home.

Following the stamp act of 1765, and the tea tax of 1767, the

Pennsylvania Colony joined hands with the others in a general tea

boycott; and coffee received the same impetus as elsewhere in the

colonies that became the thirteen original states.

The coffee houses of early Philadelphia loom large in the history of the

city and the republic. Picturesque in themselves, with their distinctive

colonial architecture, their associations also were romantic. Many a

civic, sociological, and industrial reform came into existence in the

low-ceilinged, sanded-floor main rooms of the city's early coffee

houses.

For many years, Ye coffee house, the two London coffee houses, and the

City tavern (also known as the Merchants coffee house) each in its turn

dominated the official and social life of Philadelphia. The earlier

houses were the regular meeting places of Quaker municipal officers,

ship captains, and merchants who came to transact public and private

business. As the outbreak of the Revolution drew near, fiery colonials,

many in Quaker garb, congregated there to argue against British

oppression of the colonies. After the Revolution, the leading citizens

resorted to the coffee house to dine and sup and to hold their social

functions.

When the city was founded in 1682, coffee cost too much to admit of its

being retailed to the general public at coffee houses. William Penn

wrote in his _Accounts_ that in 1683 coffee in the berry was sometimes

procured in New York at a cost of eighteen shillings nine pence the

pound, equal to about $4.68. He told also that meals were served in the

ordinaries at six pence (equal to twelve cents), to wit: "We have seven

ordinaries for the entertainment of strangers and for workmen that are

not housekeepers, and a good meal is to be had there for six pence

sterling." With green coffee costing $4.68 a pound, making the price of

a cup about seventeen cents, it is not likely that coffee was on the

menus of the ordinaries serving meals at twelve cents each. Ale was the

common meal-time beverage.

There were four classes of public houses--inns, taverns, ordinaries, and

coffee houses. The inn was a modest hotel that supplied lodgings, food,

and drink, the beverages consisting mostly of ale, port, Jamaica rum,

and Madeira wine. The tavern, though accommodating guests with bed and

board, was more of a drinking place than a lodging house. The ordinary

combined the characteristics of a restaurant and a boarding house. The

coffee house was a pretentious tavern, dispensing, in most cases,

intoxicating drinks as well as coffee.

_Philadelphia's First Coffee House_

The first house of public resort opened in Philadelphia bore the name of

the Blue Anchor tavern, and was probably established in 1683 or 1684;

colonial records do not state definitely. As its name indicates, this

was a tavern. The first coffee house came into existence about the year

1700. Watson, in one place in his _Annals_ of the city, says 1700, but

in another 1702. The earlier date is thought to be correct, and is

seemingly substantiated by the co-authors Scharf and Westcott in their

_History_ of the city, in which they say, "The first public house

designated as a coffee house was built in Penn's time [1682-1701] by

Samuel Carpenter, on the east side of Front Street, probably above

Walnut Street. That it was the first of its kind--the only one in fact

for some years--seems to be established beyond doubt. It was always

referred to in old times as 'Ye Coffee House.'"

Carpenter owned also the Globe inn, which was separated from Ye coffee

house by a public stairway running down from Front Street to Water

Street, and, it is supposed, to Carpenter's Wharf. The exact location of

the old house was recently established from the title to the original

patentee, Samuel Carpenter, by a Philadelphia real-estate

title-guarantee company, as being between Walnut and Chestnut Streets,

and occupying six and a half feet of what is now No. 137 South Front

Street and the whole of No. 139.

How long Ye coffee house endured is uncertain. It was last mentioned in

colonial records in a real estate conveyance from Carpenter to Samuel

Finney, dated April 26, 1703. In that document it is described as "That

brick Messuage, or Tenement, called Ye Coffee House, in the possession

of Henry Flower, and situate, lying and being upon or before the bank of

the Delaware River, containing in length about thirty feet and in

breadth about twenty-four."

The Henry Flower mentioned as the proprietor of Philadelphia's first

coffee house, was postmaster of the province for a number of years, and

it is believed that Ye coffee house also did duty as the post-office for

a time. Benjamin Franklin's _Pennsylvania Gazette_, in an issue

published in 1734, has this advertisement:

_All persons who are indebted to Henry Flower, late postmaster of

Pennsylvania, for Postage of Letters or otherwise, are desir'd to

pay the same to him at the old Coffee House in Philadelphia._

Flower's advertisement would indicate that Ye coffee house, then

venerable enough to be designated as old, was still in existence, and

that Flower was to be found there. Franklin also seems to have been in

the coffee business, for in several issues of the _Gazette_ around the

year 1740 he advertised: "Very good coffee sold by the Printer."

_The First London Coffee House_

Philadelphia's second coffee house bore the name of the London coffee

house, which title was later used for the resort William Bradford opened

in 1754. The first house of this name was built in 1702, but there seems

to be some doubt about its location. Writing in the _American Historical

Register_, Charles H. Browning says: "William Rodney came to

Philadelphia with Penn in 1682, and resided in Kent County, where he

died in 1708; he built the old London coffee house at Front and Market

Streets in 1702." Another chronicler gives its location as "above Walnut

Street, either on the east side of Water Street, or on Delaware Avenue,

or, as the streets are very close together, it may have been on both.

John Shewbert, its proprietor, was a parishioner of Christ Church, and

his establishment was largely patronized by Church of England people."

It was also the gathering place of the followers of Penn and the

Proprietary party, while their opponents, the political cohorts of

Colonel Quarry, frequented Ye coffee house.

The first London coffee house resembled a fashionable club house in its

later years, suitable for the "genteel" entertainments of the well-to-do

Philadelphians. Ye coffee house was more of a commercial or public

exchange. Evidence of the gentility of the London is given by John

William Wallace:

The appointments of the London Coffee House, if we may infer what

they were from the will of Mrs. Shubert [Shewbert] dated November

27, 1751, were genteel. By that instrument she makes bequest of

two silver quart tankards; a silver cup; a silver porringer; a

silver pepper pot; two sets of silver castors; a silver soup spoon;

a silver sauce spoon, and numerous silver tablespoons and tea

spoons, with a silver tea-pot.

[Illustration: THE SECOND LONDON COFFEE HOUSE, OPENED IN 1754 BY WILLIAM

BRADFORD, THE PRINTER

Up to the outbreak of the American Revolution, it was more frequented

than any other tavern in the Quaker city as a place of resort and

entertainment, and was famous throughout the colonies]

One of the many historic incidents connected with this old house was the

visit there by William Penn's eldest son, John, in 1733, when he

entertained the General Assembly of the province on one day and on the

next feasted the City Corporation.

_Roberts' Coffee House_

Another house with some fame in the middle of the eighteenth century was

Roberts' coffee house, which stood in Front Street near the first London

house. Though its opening date is unknown, it is believed to have come

into existence about 1740. In 1744 a British army officer recruiting

troops for service in Jamaica advertised in the newspaper of the day

that he could be seen at the Widow Roberts' coffee house. During the

French and Indian War, when Philadelphia was in grave danger of attack

by French and Spanish privateers, the citizens felt so great relief when

the British ship Otter came to the rescue, that they proposed a public

banquet in honor of the Otter's captain to be held at Roberts' coffee

house. For some unrecorded reason the entertainment was not given;

probably because the house was too small to accommodate all the citizens

desiring to attend. Widow Roberts retired in 1754.

_The James Coffee House_

Contemporary with Roberts' coffee house was the resort run first by

Widow James, and later by her son, James James. It was established in

1744, and occupied a large wooden building on the northwest corner of

Front and Walnut Streets. It was patronized by Governor Thomas and many

of his political followers, and its name frequently appeared in the news

and advertising columns of the _Pennsylvania Gazette_.

_The Second London Coffee House_

Probably the most celebrated coffee house in Penn's city was the one

established by William Bradford, printer of the _Pennsylvania Journal_.

It was on the southwest corner of Second and Market Streets, and was

named the London coffee house, the second house in Philadelphia to bear

that title. The building had stood since 1702, when Charles Reed, later

mayor of the city, put it up on land which he bought from Letitia Penn,

daughter of William Penn, the founder. Bradford was the first to use the

structure for coffee-house purposes, and he tells his reason for

entering upon the business in his petition to the governor for a

license: "Having been advised to keep a Coffee House for the benefit of

merchants and traders, and as some people may at times be desirous to be

furnished with other liquors besides coffee, your petitioner apprehends

it is necessary to have the Governor's license." This would indicate

that in that day coffee was drunk as a refreshment between meals, as

were spirituous liquors for so many years before, and thereafter up to

1920.

[Illustration: SELLING SLAVES AT THE OLD LONDON COFFEE HOUSE]

Bradford's London coffee house seems to have been a joint-stock

enterprise, for in his _Journal_ of April 11, 1754, appeared this

notice: "Subscribers to a public coffee house are invited to meet at the

Courthouse on Friday, the 19th instant, at 3 o'clock, to choose trustees

agreeably to the plan of subscription."

The building was a three-story wooden structure, with an attic that some

historians count as the fourth story. There was a wooden awning

one-story high extending out to cover the sidewalk before the coffee

house. The entrance was on Market (then known as High) Street.

The London coffee house was "the pulsating heart of excitement,

enterprise, and patriotism" of the early city. The most active citizens

congregated there--merchants, shipmasters, travelers from other colonies

and countries, crown and provincial officers. The governor and persons

of equal note went there at certain hours "to sip their coffee from the

hissing urn, and some of those stately visitors had their own stalls."

It had also the character of a mercantile exchange--carriages, horses,

foodstuffs, and the like being sold there at auction. It is further

related that the early slave-holding Philadelphians sold negro men,

women, and children at vendue, exhibiting the slaves on a platform set

up in the street before the coffee house.

The resort was the barometer of public sentiment. It was in the street

before this house that a newspaper published in Barbados, bearing a

stamp in accordance with the provisions of the stamp act, was publicly

burned in 1765, amid the cheers of bystanders. It was here that Captain

Wise of the brig Minerva, from Pool, England, who brought news of the

repeal of the act, was enthusiastically greeted by the crowd in May,

1766. Here, too, for several years the fishermen set up May poles.

Bradford gave up the coffee house when he joined the newly formed

Revolutionary army as major, later becoming a colonel. When the British

entered the city in September, 1777, the officers resorted to the London

coffee house, which was much frequented by Tory sympathizers. After the

British had evacuated the city, Colonel Bradford resumed proprietorship;

but he found a change in the public's attitude toward the old resort,

and thereafter its fortunes began to decline, probably hastened by the

keen competition offered by the City tavern, which had been opened a few

years before.

Bradford gave up the lease in 1780, transferring the property to John

Pemberton, who leased it to Gifford Dally. Pemberton was a Friend, and

his scruples about gambling and other sins are well exhibited in the

terms of the lease in which said Dally "covenants and agrees and

promises that he will exert his endeavors as a Christian to preserve

decency and order in said house, and to discourage the profanation of

the sacred name of God Almighty by cursing, swearing, etc., and that the

house on the first day of the week shall always be kept closed from

public use." It is further covenanted that "under a penalty of £100 he

will not allow or suffer any person to use, or play at, or divert

themselves with cards, dice, backgammon, or any other unlawful game."

[Illustration: THE CITY TAVERN, BUILT IN 1773, AND KNOWN AS THE

MERCHANTS COFFEE HOUSE

The tavern (at the left) was regarded as the largest inn of the colonies

and stood next to the Bank of Pennsylvania (center). From a print made

from a rare Birch engraving]

It would seem from the terms of the lease that what Pemberton thought

were ungodly things, were countenanced in other coffee houses of the

day. Perhaps the regulations were too strict; for a few years later the

house had passed into the hands of John Stokes, who used it as dwelling

and a store.

_City Tavern or Merchants Coffee House_

The last of the celebrated coffee houses in Philadelphia was built in

1773 under the name of the City tavern, which later became known as the

Merchants coffee house, possibly after the house of the same name that

was then famous in New York. It stood in Second Street near Walnut

Street, and in some respects was even more noted than Bradford's London

coffee house, with which it had to compete in its early days.

The City tavern was patterned after the best London coffee houses; and

when opened, it was looked upon as the finest and largest of its kind in

America. It was three stories high, built of brick, and had several

large club rooms, two of which were connected by a wide doorway that,

when open, made a large dining room fifty feet long.

Daniel Smith was the first proprietor, and he opened it to the public

early in 1774. Before the Revolution, Smith had a hard struggle trying

to win patronage from Bradford's London coffee house, standing only a

few blocks away. But during and after the war, the City tavern gradually

took the lead, and for more than a quarter of a century was the

principal gathering place of the city. At first, the house had various

names in the public mind, some calling it by its proper title, the City

tavern, others attaching the name of the proprietor and designating it

as Smith's tavern, while still others used the title, the New tavern.

The gentlefolk of the city resorted to the City tavern after the

Revolution as they had to Bradford's coffee house before. However,

before reaching this high estate, it once was near destruction at the

hands of the Tories, who threatened to tear it down. That was when it

was proposed to hold a banquet there in honor of Mrs. George Washington,

who had stopped in the city in 1776 while on the way to meet her

distinguished husband, then at Cambridge in Massachusetts, taking over

command of the American army. Trouble was averted by Mrs. Washington

tactfully declining to appear at the tavern.

After peace came, the house was the scene of many of the fashionable

entertainments of the period. Here met the City Dancing Assembly, and

here was held the brilliant fête given by M. Gerard, first accredited

representative from France to the United States, in honor of Louis XVI's

birthday. Washington, Jefferson, Hamilton, and other leaders of public

thought were more or less frequent visitors when in Philadelphia.

The exact date when the City tavern became the Merchants coffee house is

unknown. When James Kitchen became proprietor, at the beginning of the

nineteenth century, it was so called. In 1806 Kitchen turned the house

into a bourse, or mercantile exchange. By that time clubs and hotels had

come into fashion, and the coffee-house idea was losing caste with the

élite of the city.

In the year 1806 William Renshaw planned to open the Exchange coffee

house in the Bingham mansion on Third Street. He even solicited

subscriptions to the enterprise, saying that he proposed to keep a

marine diary and a registry of vessels for sale, to receive and to

forward ships' letter bags, and to have accommodations for holding

auctions. But he was persuaded from the idea, partly by the fact that

the Merchants coffee house seemed to be satisfactorily filling that

particular niche in the city life, and partly because the hotel business

offered better inducements. He abandoned the plan, and opened the

Mansion House hotel in the Bingham residence in 1807.

[Illustration: EXCHANGE COFFEE HOUSE SCENE IN "HAMILTON"

In this setting for the first act of the play by Mary P. Hamlin and

George Arliss, produced in 1918, the scenic artist aimed to give a true

historical background, and combined the features of several inns and

coffee houses in Philadelphia, Virginia, and New England as they existed

in Washington's first administration]

CHAPTER XV

THE BOTANY OF THE COFFEE PLANT

_Its complete classification by class, sub-class, order, family,

genus, and species--How the Coffea arabica grows, flowers, and

bears--Other species and hybrids described--Natural caffein-free

coffee--Fungoid diseases of coffee_

The coffee tree, scientifically known as _Coffea arabica_, is native to

Abyssinia and Ethiopia, but grows well in Java, Sumatra, and other

islands of the Dutch East Indies; in India, Arabia, equatorial Africa,

the islands of the Pacific, in Mexico, Central and South America, and

the West Indies. The plant belongs to the large sub-kingdom of plants

known scientifically as the Angiosperms, or _Angiospermæ_, which means

that the plant reproduces by seeds which are enclosed in a box-like

compartment, known as the ovary, at the base of the flower. The word

Angiosperm is derived from two Greek words, _sperma_, a seed, and

_aggeion_, pronounced angeion, a box, the box referred to being the

ovary.

This large sub-kingdom is subdivided into two classes. The basis for

this division is the number of leaves in the little plant which develops

from the seed. The coffee plant, as it develops from the seed, has two

little leaves, and therefore belongs to the class _Dicotyledoneæ_. This

word _dicotyledoneæ_ is made up of the two Greek words, _di(s)_, two,

and _kotyledon_, cavity or socket. It is not necessary to see the young

plant that develops from the seed in order to know that it had two seed

leaves; because the mature plant always shows certain characteristics

that accompany this condition of the seed.

In every plant having two seed leaves, the mature leaves are

netted-veined, which is a condition easily recognized even by the

layman; also the parts of the flowers are in circles containing two or

five parts, but never in threes or sixes. The stems of plants of this

class always increase in thickness by means of a layer of cells known as

a cambium, which is a tissue that continues to divide throughout its

whole existence. The fact that this cambium divides as long as it lives,

gives rise to a peculiar appearance in woody stems by which we can, on

looking at the stem of a tree of this type when it has been sawed

across, tell the age of the tree.

In the spring the cambium produces large open cells through which large

quantities of sap can run; in the fall it produces very thick-walled

cells, as there is not so much sap to be carried. Because these

thin-walled open cells of one spring are next to the thick-walled cells

of the last autumn, it is very easy to distinguish one year's growth

from the next; the marks so produced are called annual rings.

We have now classified coffee as far as the class; and so far we could

go if we had only the leaves and stem of the coffee plant. In order to

proceed farther, we must have the flowers of the plant, as botanical

classification goes from this point on the basis of the flowers. The

class _Dicotyledoneæ_ is separated into sub-classes according to whether

the flower's corolla (the showy part of the flower which ordinarily

gives it its color) is all in one piece, or is divided into a number of

parts. The coffee flower is arranged with its corolla all in one piece,

forming a tube-shaped arrangement, and accordingly the coffee plant

belongs to the sub-class _Sympetalæ_, or _Metachlamydeæ_, which means

that its petals are united.

[Illustration: THE COFFEE TREE, SHOWING DETAILS OF FLOWERS AND FRUIT

From a drawing by Ch. Emonts in Jardin's _Le Caféier et Le Café_]

The next step in classification is to place the plant in the proper

division under the sub-class, which is the order. Plants are separated

into orders according to their varied characteristics. The coffee plant

belongs to an order known as _Rubiales_. These orders are again divided

into families. Coffee is placed in the family _Rubiaceæ_, or Madder

Family, in which we find herbs, shrubs or trees, represented by a few

American plants, such as bluets, or Quaker ladies, small blue spring

flowers, common to open meadows in northern United States; and partridge

berries (_Mitchella repens_).

The Madder Family has more foreign representatives than native genera,

among which are _Coffea_, _Cinchona_, and _Ipecacuanha_ (_Uragoga_), all

of which are of economic importance. The members of this family are

noted for their action on the nervous system. Coffee, as is well known,

contains an active principle known as caffein which acts as a stimulant

to the nervous system and in small quantities is very beneficial.

_Cinchona_ supplies us with quinine, while _Ipecacuanha_ produces

ipecac, which is an emetic and purgative.

The families are divided into smaller sections known as genera, and to

the genus _Coffea_ belongs the coffee plant. Under this genus _Coffea_

are several sub-genera, and to the sub-genus _Eucoffea_ belongs our

common coffee, _Coffea arabica_. _Coffea arabica_ is the original or

common Java coffee of commerce. The term "common" coffee may seem

unnecessary, but there are many other species of coffee besides

_arabica_. These species have not been described very frequently;

because their native haunts are the tropics, and the tropics do not

always offer favorable conditions for the study of their plants.

All botanists do not agree in their classification of the species and

varieties of the _coffea_ genus. M.E. de Wildman, curator of the royal

botanical gardens at Brussels, in his _Les Plantes Tropicales de Grande

Culture_, says the systematic division of this interesting genus is far

from finished; in fact, it may be said hardly to be begun.

_Coffea arabica_ we know best because of the important rôle it plays in

commerce.

COMPLETE CLASSIFICATION OF COFFEE

Kingdom _Vegetable_

Sub-Kingdom _Angiospermæ_

Class _Dicotyledoneæ_

Sub-class _Sympetalæ or Metachlamydeæ_

Order _Rubiales_

Family _Rubiaceæ_

Genus _Coffea_

Sub-genus _Eucoffea_

Species _C. arabica_

The coffee plant most cultivated for its berries is, as already stated,

_Coffea arabica_, which is found in tropical regions, although it can

grow in temperate climates. Unlike most plants that grow best in the

tropics, it can stand low temperatures. It requires shade when it grows

in hot, low-lying districts; but when it grows on elevated land, it

thrives without such protection. Freeman[94] says there are about eight

recognized species of _coffea_.

[Illustration: DETAILS OF THE GERMINATION OF THE COFFEE PLANT

From a drawing by Ch. Emonts in Jardin's _Le Caféier et Le Café_]

_Coffea Arabica_

_Coffea arabica_ is a shrub with evergreen leaves, and reaches a height

of fourteen to twenty feet when fully grown. The shrub produces

dimorphic branches, _i.e._, branches of two forms, known as uprights and

laterals. When young, the plants have a main stem, the upright, which,

however, eventually sends out side shoots, the laterals. The laterals

may send out other laterals, known as secondary laterals; but no lateral

can ever produce an upright. The laterals are produced in pairs and are

opposite, the pairs being borne in whorls around the stem. The laterals

are produced only while the joint of the upright, to which they are

attached, is young; and if they are broken off at that point, the

upright has no power to reproduce them. The upright can produce new

uprights also; but if an upright is cut off, the laterals at that

position tend to thicken up. This is very desirable, as the laterals

produce the flowers, which seldom appear on the uprights. This fact is

utilized in pruning the coffee tree, the uprights being cut back, the

laterals then becoming more productive. Planters generally keep their

trees pruned down to about six feet.

The leaves are lanceolate, or lance-shaped, being borne in pairs

opposite each other. They are three to six inches in length, with an

acuminate apex, somewhat attenuate at the base, with very short petioles

which are united with the short interpetiolar stipules at the base. The

coffee leaves are thin, but of firm texture, slightly coriaceous. They

are very dark green on the upper surface, but much lighter underneath.

The margin of the leaf is entire and wavy. In some tropical countries

the natives brew a coffee tea from the leaves of the coffee tree.

[Illustration: BRAZIL COFFEE PLANTATION IN FLOWER]

The coffee flowers are small, white, and very fragrant, having a

delicate characteristic odor. They are borne in the axils of the leaves

in clusters, and several crops are produced in one season, depending on

the conditions of heat and moisture that prevail in the particular

season. The different blossomings are classed as main blossoming and

smaller blossomings. In semi-dry high districts, as in Costa Rica or

Guatemala, there is one blossoming season, about March, and flowers and

fruit are not found together, as a rule, on the trees. But in lowland

plantations where rain is perennial, blooming and fruiting continue

practically all the year; and ripe fruits, green fruits, open flowers,

and flower buds are to be found at the same time on the same branchlet,

not mixed together, but in the order indicated.

[Illustration: COFFEA ARABICA--PORTO RICO]

The flowers are also tubular, the tube of the corolla dividing into five

white segments. Dr. P.J.S. Cramer, chief of the division of plant

breeding, Department of Agriculture, Netherlands India, says the number

of petals is not at all constant, not even for flowers of the same tree.

The corolla segments are about one-half inch in length, while the tube

itself is about three-eighths of an inch long. The anthers of the

stamens, which are five in number, protrude from the top of the corolla

tube, together with the top of the two-cleft pistil. The calyx, which is

so small as to escape notice unless one is aware of its existence, is

annular, with small, tooth-like indentations.

While the usual color of the coffee flower is white, the fresh stamens

and pistils may have a greenish tinge, and in some cultivated species

the corolla is pale pink.

The size and condition of the flowers are entirely dependent on the

weather. The flowers are sometimes very small, very fragrant, and very

numerous; while at other times, when the weather is not hot and dry,

they are very large, but not so numerous. Both sets of flowers mentioned

above "set fruit," as it is called; but at times, especially in a very

dry season, they bear flowers that are few in number, small, and

imperfectly formed, the petals frequently being green instead of white.

These flowers do not set fruit. The flowers that open on a dry sunny day

show a greater yield of fruit than those that open on a wet day, as the

first mentioned have a better chance of being pollinated by the insects

and the wind. The beauty of a coffee estate in flower is of a very

fleeting character. One day it is a snowy expanse of fragrant white

blossoms for miles and miles, as far as the eye can see, and two days

later it reminds one of the lines from Villon's _Des Dames du Temps

Jadis_.

Where are the snows of yesterday?

The winter winds have blown them all away.

[Illustration: COFFEA ARABICA, FLOWER AND FRUIT--COSTA RICA]

But here, the winter winds are not to blame: the soft, gentle breezes of

the perpetual summer have wrought the havoc, leaving, however, a not

unpleasing picture of dark, cool, mossy green foliage.

The flowers are beautiful, but the eye of the planter sees in them not

alone beauty and fragrance. He looks far beyond, and in his mind's eye

he sees bags and bags of green coffee, representing to him the goal and

reward of all his toil. After the flowers droop, there appear what are

commercially known as the coffee berries. Botanically speaking, "berry"

is a misnomer. These little fruits are not berries, such as are well

represented by the grape; but are drupes, which are better exemplified

by the cherry and the peach. In the course of six or seven months, these

coffee drupes develop into little red balls about the size of an

ordinary cherry; but, instead of being round, they are somewhat

ellipsoidal, having at the outer end a small umbilicus. The drupe of the

coffee usually has two locules, each containing a little "stone" (the

seed and its parchment covering) from which the coffee bean (seed) is

obtained. Some few drupes contain three, while others, at the outer ends

of the branches, contain only one round bean, known as the peaberry. The

number of pickings corresponds to the different blossomings in the same

season; and one tree of the species _arabica_ may yield from one to

twelve pounds a year.

[Illustration: YOUNG COFFEA ARABICA TREE AT KONA, HAWAII]

In countries like India and Africa, the birds and monkeys eat the ripe

coffee berries. The so-called "monkey coffee" of India, according to

Arnold, is the undigested coffee beans passed through the alimentary

canal of the animal.

[Illustration: SURVIVORS OF THE FIRST LIBERIAN COFFEE TREES INTRODUCED

INTO JAVA IN 1876]

The pulp surrounding the coffee beans is at present of no commercial

importance. Although efforts have been made at various times by natives

to use it as a food, its flavor has not gained any great popularity, and

the birds are permitted a monopoly of the pulp as a food. From the human

standpoint the pulp, or sarcocarp, as it is scientifically called, is

rather an annoyance, as it must be removed in order to procure the

beans. This is done in one of two ways. The first is known as the dry

method, in which the entire fruit is allowed to dry, and is then cracked

open. The second way is called the wet method; the sarcocarp is removed

by machine, and two wet, slimy seed packets are obtained. These packets,

which look for all the world like seeds, are allowed to dry in such a

way that fermentation takes place. This rids them of all the slime; and,

after they are thoroughly dry, the endocarp, the so-called parchment

covering, is easily cracked open and removed. At the same time that the

parchment is removed, a thin silvery membrane, the silver skin, beneath

the parchment, comes off, too. There are always small fragments of this

silver skin to be found in the groove of the coffee bean contained

within the parchment packet.

[Illustration: COFFEA ARABICA IN FLOWER ON A JAVA ESTATE

From a photograph made at Dramaga, Preanger, Java, in 1907]

[Illustration: LIBERIAN COFFEE TREE AT LAMOA, P.I.]

We have said that the coffee tree yields from one to twelve pounds a

year, but of course this varies with the individual tree and also with

the region. In some countries the whole year's yield is less than 200

pounds per acre, while there is on record a patch in Brazil which yields

about seventeen pounds to the tree, bringing the yield per acre much

higher.

The beans do not retain their vitality for planting for any considerable

length of time; and, if they are thoroughly dried, or are kept for

longer than three or four months, they are useless for that purpose. It

takes the seed about six weeks to germinate and to appear above ground.

Trees raised from seed begin to blossom in about three years; but a good

crop can not be expected of them for the first five or six years. Their

usefulness, save in exceptional cases, is ended in about thirty years.

The coffee tree can be propagated in a way other than by seeds. The

upright branches can be used as slips, which, after taking root, will

produce seed-bearing laterals. The laterals themselves can not be used

as slips. In Central America the natives sometimes use coffee uprights

for fences and it is no uncommon sight to see the fence posts "growing."

The wood of the coffee tree is used also for cabinet work, as it is much

stronger than many of the native woods, weighing about forty-three

pounds to the cubic foot, having a crushing strength of 5,800 pounds per

square inch, and a breaking strength of 10,900 pounds per square inch.

The propagation of the coffee plant by cutting has two distinct

advantages over propagation by seed, in that it spares the expense of

seed production, which is enormous, and it gives also a method of

hybridization, which, if used, might lead not only to very interesting

but also to very profitable results.

[Illustration: TWO-AND-ONE-HALF-YEAR-OLD C. CONGENSIS]

The hybridization of the coffee plant was taken up in a thoroughly

scientific manner by the Dutch government at the experimental garden

established at Bangelan, Java, in 1900. In his studies, twelve varieties

of _Coffea arabica_ are recognized by Dr. P.J.S. Cramer[95], namely:

_Laurina_, a hybrid of _Coffea arabica_ with C. _mauritiana_,

having small narrow leaves, stiff, dense branches, young leaves

almost white, berry long and narrow, and beans narrow and oblong.

_Murta_, having small leaves, dense branches, beans as in the

typical _Coffea arabica_, and the plant able to stand bitter cold.

_Menosperma_, a distinct type, with narrow leaves and bent-down

branches resembling a willow, the berries seldom containing more

than one seed.

[Illustration: A HEAVY FLOWERING OF FIVE-YEAR-OLD COFFEA EXCELSA

This is a comparatively new species, discovered in the Tchad Lake

district of West Africa in 1905. It is a small-beaned variety of _Coffea

liberica_]

[Illustration: BRANCHES OF COFFEA EXCELSA GROWN AT THE LAMAO EXPERIMENT

STATION, P.I.]

_Mokka_ (_Coffea Mokkæ_), having small leaves, dense foliage, small

round berries, small round beans resembling split peas, and

possessed of a stronger flavor than _Coffea arabica_.

_Purpurescens_, a red-leaved variety, comparable with the

red-leaved hazel and copper beech, a little less productive than

the _Coffea arabica_.

_Variegata_, having variegated leaves striped and spotted with

white.

_Amarella_, having yellow berries, comparable with the

white-fruited variety of the strawberry, raspberry, etc.

_Bullata_, having broad, curled leaves; stiff, thick, fragile

branches, and round, fleshy berries containing a high percentage of

empty beans.

_Angustifolia_, a narrow-leaved variety, with berries somewhat more

oblong and, like the foregoing, a poor producer.

_Erecta_, a variety that is sturdier than the typical _arabica_,

better suited to windy places, and having a production as in the

common _arabica_.

_Maragogipe_, a well-defined variety with light green leaves having

colored edges: berries large, broad, sometimes narrower in the

middle; a light bearer, the whole crop sometimes being reduced to a

couple of berries per tree.[96]

[Illustration: C. STENOPHYLLA, FROM WHICH IS OBTAINED THE HIGHLAND

COFFEE OF SIERRA LEONE]

_Columnaris_, a vigorous variety, sometimes reaching a height of 25

feet, having leaves rounded at the base and rather broad, but a shy

bearer, recommended for dry climates.

_Coffea Stenophylla_

_Coffea arabica_ has a formidable rival in the species _stenophylla_.

The flavor of this variety is pronounced by some as surpassing that of

_arabica_. The great disadvantage of this plant is the fact that it

requires so long a time before a yield of any value can be secured.

Although the time required for the maturing of the crop is so long, when

once the plantation begins to yield, the crop is as large as that of

_Coffea arabica_, and occasionally somewhat larger. The leaves are

smaller than any of the species described, and the flowers bear their

parts in numbers varying from six to nine. The tree is a native of

Sierra Leone, where it grows wild.

[Illustration: Copyright, 1909, by The Tea and Coffee Trade Journal

NEAR VIEW OF COFFEE BERRIES OF COFFEA ARABICA]

_Coffea Liberica_

The bean of _Coffea arabica_, although the principal bean used in

commerce, is not the only one; and it may not be out of place here to

describe briefly some of the other varieties that are produced

commercially. _Coffea liberica_ is one of these plants. The quality of

the beverage made from its berries is inferior to that of _Coffea

arabica_, but the plant itself offers distinct advantages in its hardy

growing qualities. This makes it attractive for hybridization.

[Illustration: WILD "CAFFEIN-FREE" COFFEE TREE

_Mantsaka_ or _Café Sauvage_--Madagascar]

The _Coffea liberica_ tree is much larger and sturdier than the _Coffea

arabica_, and in its native haunts it reaches a height of 30 feet. It

will grow in a much more torrid climate and can stand exposure to strong

sunlight. The leaves are about twice as long as those of _arabica_,

being six to twelve inches in length, and are very thick, tough, and

leathery. The apex of the leaf is acute. The flowers are larger than

those of _arabica_, and are borne in dense clusters. At any time during

the season, the same tree may bear flowers, white or pinkish, and

fragrant, or even green, together with fruits, some green, some ripe and

of a brilliant red. The corolla has been known to have seven segments,

though as a rule it has five. The fruits are large, round, and dull red;

the pulps are not juicy, and are somewhat bitter. Unlike _Coffea

arabica_, the ripened drupes do not fall from the trees, and so the

picking can be delayed at the planter's convenience.

[Illustration: DIFFERENTIATING CHARACTERISTICS OF COFFEE BEANS, IN

CROSS-SECTION

Col. I. Mature bean. Col. II. Embryo.

_A. Coffea arabica, R. Coffea robusta, L. Coffea liberica_]

Among the allied Liberian species Dr. Cramer recognizes:

_Abeokutæ_, having small leaves of a bright green, flower buds

often pink just before opening (in Liberian coffee never), fruit

smaller with sharply striped red and yellow shiny skin, and

producing somewhat smaller beans than Liberian coffee, but beans

whose flavor and taste are praised by brokers;

_Dewevrei_, having curled edged leaves, stiff branches,

thick-skinned berries, sometimes pink flowers, beans generally

smaller than in _C. liberica_, but of little interest to the trade;

_Arnoldiana_, a species near to _Coffea Abeokutæ_ having darker

foliage and the even colored small berries;

_Laurentii Gillet_, a species not to be confused with the _C.

Laurentii_ belonging to the _robusta_ coffee, but standing near to

_C. liberica_, characterized by oblong rather than thin-skinned

berries;

_Excelsa_, a vigorous, disease-resisting species discovered in 1905

by Aug. Chevalier in West Africa, in the region of the Chari River,

not far from Lake Tchad. The broad, dark-green leaves have an under

side of light green with a bluish tinge; the flowers are large and

white, borne in axillary clusters of one to five; the berries are

short and broad, in color crimson, the bean smaller than _robusta_,

very like _Mocha_, but in color a bright yellow like _liberica_.

The caffein content of the coffee is high, and the aroma is very

pronounced;

_Dybowskii_, another disease-resisting variety similar to

_excelsa_, but having different leaf and fruit characteristics;

_Lamboray_, having bent gutter-like leaves, and soft-skinned,

oblong fruit;

_Wanni Rukula_, having large leaves, a vigorous growth, and small

berries;

_Coffea aruwimensis_, being a mixture of different types.

[Illustration: COFFEA ARABICA BERRIES GROWN IN THE HAWAIIAN ISLANDS]

The last three types were received by Dr. Cramer at Bangelan from Frère

Gillet in the Belgian Congo, and were still under trial in Java in 1919.

_Coffea Robusta_

Emil Laurent, in 1898, discovered a species of coffee growing wild in

Congo. This was taken up by a horticultural firm of Brussels, and

cultivated for the market. This firm gave to the coffee the name _Coffea

robusta_, although it had already been given the name of the discoverer,

being known as _Coffea Laurentii_. The plant differs widely from both

_arabica_ and _liberica_, being considerably larger than either. The

tree is umbrella-shaped, due to the fact that its branches are very long

and bend toward the ground.

The leaves of _robusta_ are much thinner than those of _liberica_,

though not as thin as those of _arabica_. The tree, as a whole, is a

very hardy variety and even bears blossoms when it is less than a year

old. It blossoms throughout the entire year, the flowers having

six-parted corollas. The drupes are smaller than those of _liberica;_

but are much thinner skinned, so that the coffee bean is actually not

any smaller. The drupes mature in ten months. Although the plants bear

as early as the first year, the yield for the first two years is of no

account; but by the fourth year the crop is large.

[Illustration: ROBUSTA COFFEE IN FLOWER, PREANGER, JAVA]

[Illustration: COFFEE ESTATE IN THE LUQUILLO MOUNTAINS, PORTO RICO]

[Illustration: JAPANESE LABORERS PICKING COFFEE ON KONA SIDE, ISLAND OF

HAWAII]

[Illustration: COFFEE UNDER THE STARS AND STRIPES]

Arno Viehoever, pharmacognosist in charge of the pharmacognosy

laboratory of the Bureau of Chemistry, United States Department of

Agriculture, has recently announced findings confirming Hartwich which

appear to permit of differentiation between _robusta, arabica_, and

_liberica_.[97] These are mainly the peculiar folding of the endosperm,

showing quite generally a distinct hook in the case of the _robusta_

coffee bean. The size of the embryo, and especially the relation of the

rootlet to hypercotyl, will be found useful in the differentiation of

the species _Coffea arabica, liberica_, and _robusta_ (see cut, page

142).

[Illustration: ONE-YEAR-OLD ROBUSTA ESTATE, ON SUMATRA'S WEST COAST]

Viehoever and Lepper carried on a series of cup tests of _robusta_, the

results as to taste and flavor being distinctly favorable. They

summarized their studies and tests as follows:

The time when coffee could be limited to beans obtained from plants

of _Coffea arabica_ and _Coffea liberica_ has passed. Other

species, with qualities which make them desirable, even in

preference to the well reputed named ones, have been discovered and

cultivated. Among them, the species or group of _Coffea robusta_

has attained a great economic significance, and is grown in

increasing amounts. While it has, as reports seem to indicate, not

as yet been possible to obtain a strain that would be as desirable

in flavor as the old "standard" _Coffea_ _arabica_, well known as

Java or "Fancy Java" coffee, its merits have been established.

The botanical origin is not quite cleared up, and the

classification of the varieties belonging to the _robusta_ group

deserves further study. Anatomical means of differentiating

_robusta_ coffee from other species or groups, may be applied as

distinctly helpful....

As is usual in most of the coffee species, caffein is present. The

amount appears to be, on an average, somewhat larger (even

exceeding 2.0 percent) than in the South American coffee species.

In no instance, however, did the amount exceed the maximum limits

observed in coffee in general....

Due to its rapid growth, early and prolific yield, resistance to

coffee blight, and many other desirable qualities, _Coffea robusta_

has established "its own". In the writers' judgment, _robusta_

coffee deserves consideration and recognition.

Among the _robusta_ varieties, _Coffea canephora_ is a distinct species,

well characterized by growth, leaves, and berries. The branches are

slender and thinner than _robusta_; the leaves are dark green and

narrower; the flowers are often tinged with red; the unripe berries are

purple, the ripe berries bright red and oblong. The produce is like

_robusta_, only the shape of the bean, somewhat narrower and more

oblong, makes it look more attractive. _Coffea canephora_, like _C.

robusta_, seems better fitted to higher altitudes.

Other _canephora_ varieties include:

_Madagascar_, having small, slightly striped, bright red berries and

small round beans;

_Quillouensis_, having dark green foliage and reddish brown young

leaves; and,

_Stenophylla Paris_, with purplish young berries.

These last two named were under test at the Bangelan gardens in 1919.

Among other allied _robusta_ species are:

_Ugandæ_:, whose produce is said to possess a better flavor than

_robusta_;

_Bukobensis_, different from _Ugandæ_ in the color of its berries, which

are a dark red; and

_Quillou_, having bright red fruit, a copper-colored silver skin, three

pounds of fruit producing one pound of market coffee. Some people prefer

_Quillou_ to _robusta_ because of the difference in the taste of the

roasted bean.

_Some Interesting Hybrids_

The most popular hybrid belongs to a crossing of _liberica_ and

_arabica_. Cramer states that the beans of this hybrid make an excellent

coffee combining the strong taste of the _liberica_ with the fine flavor

of the old Government Java _(arabica_), adding:

The hybrids are not only of value to the roaster, but also to the

planter. They are vigorous trees, practically free from leaf

disease; they stand drought well and also heavy rains; they are not

particular in regard to shade and upkeep; never fail to give a fair

and often a rather heavy crop. The fruit ripens all the year

around, and does not fall so easily as in the case of _arabica_.

Among other hybrids (many were still under trial in 1919) may be

mentioned: _Coffea excelsia x liberica_; _C. Abeokutæ x liberica_; _C.

Dybowskii x excelsa_; _C. stenophylla x Abeokutæ_; _C. congensis x

Ugandæ_; _C. Ugandæ x congensis_; and _C. robusta x Maragogipe_.

There are many species of _Coffea_ that stand quite apart from the main

groups, _arabica, robusta_ and _liberica_; but while some are of

commercial value, most of them are interesting only from the scientific

point of view. Among the latter may be mentioned: _Coffea bengalensis_,

_C. Perieri_, _C. mauritiana_, _C. macrocarpa_, _C. madagascariensis_,

and _C. schumanniana_.

[Illustration: COFFEA QUILLOU FLOWERS IN FULL BLOOM]

M. Teyssonnier, of the experimental garden at Camayenne, French Guinea,

West Africa, has produced a promising species of coffee known as

_affinis_. It is a hybrid of _C. stenophylla_ with a species of

_liberica_.

Among other promising species recognized by Dr. Cramer are:

_Coffea congensis_, whose berry resembles that of _C. arabica_, when

well prepared for the market being green or bluish; and

_Coffea congensis var. Chalotii_, probably a hybrid of _C. congensis_

with _C. canephora_.

_Caffein-free Coffee_

Certain trees growing wild in the Comoro Islands and Madagascar are

known as caffein-free coffee trees. Just whether they are entitled to

this classification or not is a question. Some of the French and German

investigators have reported coffee from these regions that was

absolutely devoid of caffein. It was thought at first that they must

represent an entirely new genus; but upon investigation, it was found

that they belonged to the genus _Coffea_, to which all our common

coffees belong. Professor Dubard, of the French National Museum and

Colonial Garden, studied these trees botanically and classified them as

_C. Gallienii_, _C. Bonnieri_, _C. Mogeneti_, and _C. Augagneuri_. The

beans of berries from these trees were analyzed by Professor Bertrand

and pronounced caffein-free; but Labroy, in writing of the same coffee,

states that, while the bean is caffein-free, it contains a very bitter

substance, cafamarine, which makes the infusion unfit for use. Dr. O.W.

Willcox[98], in examining some specimens of wild coffee from Madagascar,

found that the bean was not caffein-free; and though the caffein content

was low, it was no lower than in some of the Porto Rican varieties.

Hartwich[99] reports that Hanausek found no caffein in _C. mauritiana_,

_C. humboltiana_, _C. Gallienii_, _C. Bonnerii_, and _C. Mogeneti_.

_Fungoid Disease of Coffee_

The coffee tree, like every other living thing, has specific diseases

and enemies, the most common of which are certain fungoid diseases where

the mycelium of the fungus grows into the tissue and spots the leaves,

eventually causing them to fall, thus robbing the plant of its only

means of elaborating food. Its most deadly enemy in the insect world is

a small insect of the lepidopterous variety, which is known as the

coffee-leaf miner. It is closely related to the clothes moth and, like

the moth, bores in its larval stage, feeding on the mesophyl of the

leaves. This gives the leaves an appearance of being shriveled or dried

by heat.

[Illustration: AN EIGHTEEN-MONTHS'-OLD COFFEA QUILLOU TREE IN BLOSSOM]

There are three principal diseases, due to fungi, from which the coffee

plants suffer. The most common is known as the leaf-blight fungus,

_Pellicularia tokeroga_, which is a slow-spreading disease, but one that

causes great loss. Although the fungus does not produce spores, the

leaves die and dry, and are blown away, carrying with them the dried

mycelium of the fungus. This mycelium will start to grow as soon as it

is supplied with a new moist coffee leaf to nourish it. The method of

getting rid of this disease is to spray the trees in seasons of drought.

It was a fungoid disease known as the _Hemileia vastatrix_ that attacked

Ceylon's coffee industry in 1869, and eventually destroyed it. It is a

microscopic fungus whose spores, carried by the wind, adhere to and

germinate upon the leaves of the coffee tree[100].

Another common disease is known as the root disease, which eventually

kills the tree by girdling it below the soil. It spreads slowly, but

seems to be favored by collections of decaying matter around the base of

the tree. Sometimes the digging of ditches around the roots is

sufficient to protect it. The other common disease is due to _Stilbium

flavidum_, and is found only in regions of great humidity. It affects

both the leaf and the fruit and is known as the spot of leaf and fruit.

[Illustration: COFFEA UGANDÆ BENT OVER BY A HEAVY CROP]

CHAPTER XVI

THE MICROSCOPY OF THE COFFEE FRUIT

_How the beans may be examined under the microscope, and what is

revealed--Structure of the berry, the green, and the roasted

bean--The coffee leaf disease under the microscope--Value of

microscopic analysis in detecting adulteration_

The microscopy of coffee is, on the whole, more important to the planter

than to the consumer and the dealer; while, on the other hand, the

microscopy is of paramount importance to the consumer and the dealer as

furnishing the best means of determining whether the product offered is

adulterated or not. Also, from this standpoint, the microscopy of the

plant is less important than that of the bean.

[Illustration: Fig. 331. Coffee (_Coffea arabica_). I--Cross-section of

berry, natural size; _Pk_, outer pericarp; _Mk_, endocarp; _Ek_,

spermoderm; _Sa_, hard endosperm; Sp, soft endosperm. II--Longitudinal

section of berry, natural size; _Dis_, bordered disk; _Se_, remains of

sepals; _Em_, embryo. III--Embryo, enlarged; _cot_, cotyledon; _rad_,

radicle. (Tschirch and Oesterle.)]

_The Fruit and the Bean_

The fruit, as stated in chapter XV, consists of two parts, each one

containing a single seed, or bean. These beans are flattened laterally,

so as to fit together, except in the following instances: in the

peaberry, where one of the ovules never develops, the single ovule,

having no pressure upon it, is spherical; in the rare instances where

three seeds are found, the grains are angular.

The coffee bean with which the consumer is familiar is only a small part

of the fruit. The fruit, which is the size of a small cherry, has, like

the cherry, an outer fleshy portion called the pericarp. Beneath this is

a part like tissue paper, spoken of technically as the parchment, but

known scientifically as the endocarp. Next in position to this, and

covering the seed, is the so-called spermoderm, which means the seed

skin, referred to in the trade as the silver skin. Small portions of

this silver skin are always to be found in the cleft of the coffee bean.

The coffee bean is the embryo and its food supply; the embryo is that

part of the seed which, when supplied with food and moisture, develops

into a new plant. The embryo of the coffee is very minute (Fig. 331,

II, _Em_)[101]; and the greater part of the seed is taken up by the food

supply, consisting of hard and soft endosperm (Fig. 331, I and II, _Sa_,

_Sp_). The minute embryo consists of two small thick leaves, the

cotyledons (Fig. 331, III, _cot_), a short stem, invisible in the

undissected embryo, and a small root, the radicle (Fig. 331, III,

_rad_).

[Illustration: Fig. 332. Coffee. Cross section of bean showing folded

endosperm with hard and soft tissues. x6. (Moeller)]

_Fruit Structure_

In order to examine the structure of these layers of the fruit under the

microscope, it is necessary to use the pericarp dry, as it is not easily

obtainable in its natural condition. If desired, an alcoholic specimen

may be used, but it has been found that the dry method gives more

satisfactory results. The dried pericarp is about 0.5 mm thick. Great

difficulty is experienced in cutting microtome sections of pericarp when

the specimen is embedded in paraffin, because the outer layers are soft

and the endocarp is hard, and the two parts of the section separate at

this point. To overcome this, the sections might also be embedded in

celloidin. When the sections are satisfactory, they may be stained with

any of the double stains ordinarily used in the study of plant

histology.

[Illustration: Fig. 333. Coffee. Cross section of hull and bean.

Pericarp consists of: 1, epicarp; 2-3, layers of mesocarp, with 4,

fibro-vascular bundle; 5, palisade layer; and 6, endocarp; _ss_,

spermoderm, consists of 8, sclerenchyma, and 9, parenchyma; _End_,

endosperm (Tschirch and Oesterle)]

A section cut crosswise through the entire fruit would present the

appearance shown in Fig. 333. The cells of the epicarp are broad and

polygonal, sometimes regularly four-sided, about 15-35 µ broad. At

intervals along the surface of the epicarp are stomata, or breathing

pores, surrounded by guard cells. The next layer of the pericarp is the

mesocarp (Figs. 333, 334, 335), the cells of which are larger and more

regular in outline than the epicarp. The cells of the mesocarp become as

large as 100 µ broad, but in the inner parts of the layer they become

very much flattened. Fibrovascular bundles are scattered through the

compressed cells of the mesocarp. The cell walls are thick; and large,

amorphous, brown masses are found within the cell; occasionally, large

crystals are found in the outer part of the layer. The fibro-vascular

bundles consist mainly of bast and wood fibers and vessels. The bast

fibers are as large as 1 mm long and 25 µ broad, with thick walls and

very small _lumina_. Spiral and pitted vessels are also present.

[Illustration: Fig. 334. Coffee. Surface view of _ep_, epicarp, and _p_,

outer parenchyma of mesocarp. x160. (Moeller)]

The layer next to this is a soft tissue, parenchyma (Fig. 333, 5; Fig.

334, _p_). The parenchyma, or palisade cells as they are called, is a

thin-walled tissue in which the cells are elongated, from which fact

they receive their name. The walls of these cells, though very thin, are

mucilaginous, and capable of taking up large amounts of water. They

stain well with the aniline stains.

The endocarp (Fig. 336) is closely connected with the palisade layer and

has thin-walled cells that closely resemble, in all respects, the

endocarp of the apple. The outer layer consists of thick-walled fibers,

which are remarkably porous (Fig. 333, 6; Fig. 336) while the fibers of

the inner layer are thin-walled and run in the transverse direction.

_The Bean Structure_

Spermoderm, or silver skin, is not difficult to secure for microscopic

analysis; because shreds of it remain in the groove of the berry, and

these shreds are ample for examination. It can readily be removed

without tearing, if soaked in water for a few hours. The spermoderm is

thin enough not to need sectioning. It consists of two

elements--sclerenchyma and parenchyma cells. (Figs. 333, 337, _st_,

_p_).

[Illustration: Fig. 335. Coffee. Elements of pericarp in surface view.

_p_, parenchyma; _bp_, parenchyma of fibro-vascular bundle; _b_, bast

fiber; _sp_, spiral vessel. x160. (Moeller)]

Sclerenchyma forms an uninterrupted covering in the early stages of the

seed; but as the seed develops, surrounding tissues grow more rapidly

than the sclerenchyma, and the cells are pushed apart and scattered. The

cells occurring in the cleft of the berry are straight, narrow, and

long, becoming as long as 1 mm, and resemble bast fibers somewhat. On

the surface of the berry, and sometimes in the cleft, there are found

smaller, thicker cells, which are irregular in outline, club-shaped and

vermiform types predominating.

Parenchyma cells form the remainder of the spermoderm; and these are

partially obliterated, so that the structure is not easily seen,

appearing almost like a solid membrane. The raphe runs through the

parenchyma found in the cleft of the berry.

The endosperm (Figs. 333; 338) consist of small cells in the outer part,

and large cells, frequently as thick as 100 µ, in the inner part. The

cell walls are thickened and knotted. Certain of the inner cells have

mucilaginous walls which when treated with water disappear, leaving only

the middle lamellae, which gives the section a peculiar appearance. The

cells contain no starch, the reserve food supply being stored cellulose,

protein, and aleurone grains. Various investigators report the presence

of sugar, tannin, iron, salts, and caffein.

The embryo (Fig. 331, III) may be obtained by soaking the bean in water

for several hours, cutting through the cleft and carefully breaking

apart the endosperm. If it is now soaked in diluted alkali, the embryo

protrudes through the lower end of the endosperm. It is then cleared in

alkali, or in chloral hydrate. The cotyledons shown have three pairs of

veins, which are slightly netted. The radicle is blunt and is about 3/4

mm in length, while the cotyledons are 1/2 mm long.

[Illustration: Fig. 336. Coffee. Sclerenchyma fibers of endocarp. x160.

(Moeller)]

_The Coffee-Leaf Disease_

The coffee tree has many pests and diseases; but the disease most feared

by planters is that generally referred to as the coffee-leaf disease,

and by this is meant the fungoid _Hemileia vastatrix_, which as told in

chapter XV, destroyed Ceylon's once prosperous coffee industry. As it

has since been found in nearly all coffee-producing countries, it has

become a nightmare in the dreams of all coffee planters. The microscope

shows how the spores of this dreaded fungus, carried by the winds upon a

leaf of the coffee tree, proceed to germinate at the expense of the

leaf; robbing it of its nourishment, and causing it to droop and to die.

A mixture of powdered lime and sulphur has been found to be an effective

germicide, if used in time and diligently applied.

[Illustration: Fig. 337. Coffee. Spermoderm in surface view. _st._

sclerenchyma; _p_, compressed parenchyma. x160. (Moeller)]

[Illustration: Fig. 338. Coffee. Cross-section of outer layers of

endosperm, showing knotty thickenings of cell walls. x160. (Moeller)]

[Illustration: Fig. 339. Coffee. Tissues of embryo in section. x160.

(Moeller)]

_Value of Microscopic Analysis_

The value of the microscopic analysis of coffee may not be apparent at

first sight; but when one realizes that in many cases the microscopic

examination is the only way to detect adulteration in coffee, its

importance at once becomes apparent. In many instances the chemical

analysis fails to get at the root of the trouble, and then the only

method to which the tester has recourse is the examination of the

suspected material under the scope. The mixing of chicory with coffee

has in the past been one of the commonest forms of adulteration. The

microscopic examination in this connection is the most reliable. The

coffee grain will have the appearance already described.

Microscopically, chicory shows numerous thin-walled parenchymatous

cells, lactiferous vessels, and sieve tubes with transverse plates.

There are also present large vessels with huge, well-defined pits.

[Illustration: COFFEE LEAF DISEASE (HEMILEIA VASTATRIX)

1. under surface of affected leaf, x 1/2; 2, section through same

showing mycelium, haustoria, and a spore-cluster; 3, a spore-cluster

seen from below; 4, a uredospore; 5, germinating uredospore; 6,

appressorial swellings at tips of germ-tubes; 7, infection through stoma

of leaf; 8, teleutospores; 9, teleutospore germinating with promycelium

and sporidia; 10, sporidia and their germination (2 after Zimmermann, 3

after Delacroix, 4-10 after Ward)]

Roasted date stones have been used as adulterants, and these can be

detected quite readily with the aid of the microscope, as they have a

very characteristic microscopic appearance. The epidermal cells are

almost oblong, while the parenchymatous cells are large, irregular and

contain large quantities of tannin.

Adulteration and adulterants are considered more fully in chapter XVII.

[Illustration: GREEN AND ROASTED COFFEE UNDER THE MICROSCOPE

Green bean, showing the size and form of the cells as well as the drops

of oil contained within their cavities. Drawn with the camera lucida,

and magnified 140 diameters.

A fragment of roasted coffee under the microscope. Drawn with the camera

lucida, and magnified 140 diameters.]

[Illustration: BOGOTA, GREEN

Longitudinal--Magnified 200 diameters]

[Illustration: BOGOTA, GREEN

Cross Section--Magnified 200 diameters]

[Illustration: BOGOTA, GREEN

Tangential--Magnified 200 diameters]

[Illustration: BOGOTA, ROASTED

Tangential--Magnified 200 diameters]

[Illustration: GREEN AND ROASTED BOGOTA COFFEE UNDER THE MICROSCOPE

These pictures serve to demonstrate that the coffee bean is made up of

minute cells that are not broken down to any extent by the roasting

process. Note that the oil globules are more prominent in the green than

in the roasted product]

CHAPTER XVII

THE CHEMISTRY OF THE COFFEE BEAN

_Chemistry of the preparation and treatment of the green

bean--Artificial aging--Renovating damaged

coffees--Extracts--"Caffetannic acid"--Caffein, caffein-free

coffee--Caffeol--Fats and oils--Carbohydrates--Roasting--Scientific

aspects of grinding and packaging--The coffee brew--Soluble

coffee--Adulterants and substitutes--Official methods of analysis_

By Charles W. Trigg

Industrial Fellow of the Mellon Institute of Industrial Research,

Pittsburgh, 1916-1920

When the vast extent of the coffee business is considered, together with

the intimate connection which coffee has with the daily life of the

average human, the relatively small amount of accurate knowledge which

we possess regarding the chemical constituents and the physiological

action of coffee is productive of amazement.

True, a painstaking compilation of all the scientific and

semi-scientific work done upon coffee furnishes quite a compendium of

data, the value of which is not commensurate with its quantity, because

of the spasmodic nature of the investigations and the non-conclusive

character of the results so far obtained. The following general survey

of the field argues in favor of the promulgation of well-ordered and

systematic research, of the type now in progress at several places in

the United States, into the chemical behavior of coffee throughout the

various processes to which it is subjected in the course of its

preparation for human consumption.

_Green Coffee_

One of the few chemical investigations of the growing tree is the

examination by Graf of flowers from 20-year-old coffee trees, in which

he found 0.9 percent caffein, a reducing sugar, caffetannic acid, and

phytosterol. Power and Chestnut[102] found 0.82 percent caffein in

air-dried coffee leaves, but only 0.087 percent of the alkaloid in the

stems of the plant separated from the leaves. In the course of a

study[103] instituted for the purpose of determining the best

fertilizers for coffee trees, it developed that the cherries in

different stages of growth show a preponderance of potash throughout,

while the proportion of P_2_O_5 attains a maximum in the fourth month

and then steadily declines.

Experiments are still in progress to ascertain the precise mineral

requirements of the crop as well as the most suitable stage at which to

apply them. During the first five months the moisture content undergoes

a steady decrease, from 87.13 percent to 65.77 percent, but during the

final ripening stage in the last month there is a rise of nearly 1

percent. This may explain the premature falling and failure to ripen of

the crop on certain soils, especially in years of low rainfall.

Malnutrition of the trees may result also in the production of oily

beans.[104]

The coffee berry comprises about 68 percent pulp, 6 percent parchment,

and 26 percent clean coffee beans. The pulp is easily removed by

mechanical means; but in order to separate the soft, glutinous,

saccharine parchment, it is necessary to resort to fermentation, which

loosens the skin so that it may be removed easily, after which the

coffee is properly dried and aged. There is first a yeast fermentation

producing alcohol; and then a bacterial action giving mainly inactive

lactic acid, which is the main factor in loosening the parchment. For

the production of the best coffee, acetic acid fermentation (which

changes the color of the bean) and temperature above 60° should be

avoided, as these inhibit subsequent enzymatic action.[105]

Various schemes have been proposed for utilizing the large amount of

pulp so obtained in preparing coffee for market. Most of these depend

upon using the pulp as fertilizer, since fresh pulp contains 2.61

percent nitrogen, 0.81 percent P_2_O_5, 2.38 percent potassium, and

0.57 percent calcium. One procedure[106] in particular is to mix pulp

with sawdust, urine, and a little lime, and then to leave this mixture

covered in a pit for a year before using. In addition to these mineral

matters, the pulp also contains about 0.88 percent of caffein and 18 to

37 percent sugars. Accordingly, it has been proposed[107] to extract the

caffein with chloroform, and the sugars with acidulated water. The

aqueous solution so obtained is then fermented to alcohol. The insoluble

portion left after extraction can be used as fuel, and the resulting ash

as fertilizer.

The pulp has been dried and roasted for use in place of the berry, and

has been imported to England for this purpose. It is stated that the

Arabs in the vicinity of Jiddah discard the kernel of the coffee berries

and make an infusion of the husk.[108]

Quality of green coffee is largely dependent upon the methods used and

the care taken in curing it, and upon the conditions obtaining in

shipment and storage. True, the soil and climatic conditions play a

determinative rôle in the creation of the characteristics of coffee, but

these do not offer any greater opportunity for constructive research and

remunerative improvement than does the development of methods and

control in the processes employed in the preparation of green coffee for

the market.

[Illustration: CROSS-SECTION OF THE ENDOSPERM OR HARD STRUCTURE OF THE

GREEN BEAN]

Storage prior and subsequent to shipment, and circumstances existing

during transportation, are not to be disregarded as factors contributory

to the final quality of the coffee. The sweating of mules carrying bags

of poorly packed coffee, and the absorption of strong foreign aromas and

flavors from odoriferous substances stored in too close proximity to the

coffee beans, are classic examples of damage that bear iterative

mention. Damage by sea water, due more to the excessive moisture than to

the salt, is not so common an occurrence now as heretofore. However, a

cheap and thoroughly effective means of ethically renovating coffee

which has been damaged in this manner would not go begging for

commercial application.

That green coffee improves with age, is a tenet generally accepted by

the trade. Shipments long in transit, subjected to the effects of

tropical heat under closely battened hatches in poorly ventilated holds,

have developed into much-prized yellow matured coffee. Were it not for

the large capital required and the attendant prohibitive carrying

charges, many roasters would permit their coffees to age more thoroughly

before roasting. In fact, some roasters do indulge this desire in regard

to a portion of their stock. But were it feasible to treat and hold

coffees long enough to develop their attributes to a maximum, still the

exact conditions which would favor such development are not definitely

known. What are the optimum temperature and the correct humidity to

maintain, and should the green coffee be well ventilated or not while in

storage? How long should coffee be stored under the most favorable

conditions best to develop it? Aging for too long a period will develop

flavor at the expense of body; and the general cup efficiency of some

coffees will suffer if they be kept too long.

[Illustration: PORTION OF THE INVESTING MEMBRANE, SHOWING ITS STRUCTURE

Drawn with the camera lucida, and magnified 140 diameters]

The exact reason for improvement upon aging is in no wise certain, but

it is highly probable that the changes ensuing are somewhat analogous to

those occurring in the aging of grain. Primarily an undefined enzymatic

and mold action most likely occurs, the nature of the enzymes and molds

being largely dependent upon the previous treatment of the coffee. Along

with this are a loss of moisture and an oxidation, all three actions

having more evident effects with the passage of time.

_Artificial Aging_

In consideration of the higher prices which aged products demand,

attempts have naturally been made to shorten by artificial means the

time necessary for their natural production. Some of these methods

depend upon obtaining the most favorable conditions for acceleration of

the enzyme action; others, upon the effects of micro-organisms; and

still others, upon direct chemical reaction or physical alteration of

the green bean.

One of the first efforts toward artificial maturing was that of

Ashcroft[109], who argued from the improved nature of coffee which had

experienced a delayed voyage. His method consisted of inclosing the

coffee in sweat-boxes having perforated bottoms and subjecting it to the

sweating action of steam, the boxes being enclosed in an oven or room

maintained at the temperature of steam.

[Illustration: STRUCTURE OF THE GREEN BEAN

Showing thick-walled cells enclosing drops of oil]

Timby[110] claimed to remove dusts, foreign odors, and impurities, while

attaining in a few hours or days a ripening effect normally secured only

in several seasons. In this process, the bagged coffee is placed in

autoclaves and subjected to the action of air at a pressure of 2 to 3

atmospheres and a temperature of 40° to 100° F. The temperature should

seldom be allowed to rise above 150° F. The pressure is then allowed to

escape and a partial vacuum created in the apparatus. This alteration of

pressure and vacuum is continued until the desired maturation is

obtained. Desvignes[111] employs a similar procedure, although he

accomplishes seasoning by treating the coffee also with oxygen or

ozone.[112] First the coffee is rendered porous by storage in a hot

chamber, which is then exhausted prior to admission of the oxygen. The

oxygen can be ozonized in the closed vessel while in contact with the

coffee. Complete aging in a few days is claimed.

Weitzmann[113] adopts a novel operation, by exposing bags of raw coffee

to the action of a powerful magnetic field, obtained with two adjustable

electro-magnets. The claim that a maturation naturally produced in

several years is thus obtained in 1/2 to 2 hours is open to considerable

doubt. A process that is probably attended with more commercial success

is that of Gram[114] in which the coffee is treated with gaseous

nitrogen dioxid.

By far the most notable progress in this field, both scientifically and

commercially, has been made by Robison[115] with his "culturing" method.

Here the green coffee is washed with water, and then inoculated with

selected strains of micro-organisms, such as _Ochraeceus_ or

_Aspergillus Wintii_. Incubation is then conducted for 6 to 7 days at

90° F. and 85 percent relative humidity. Subsequent to this incubation,

the coffee is stored in bins for about ten days; after which it is

tumbled and scoured. With this process it is possible to improve the

cupping qualities of a coffee to a surprising degree.

_Renovating Damaged Coffees_

Sophistication has often been resorted to in order ostensibly to improve

damaged or cheap coffee. Glazing, coloring, and polishing of the green

beans was openly and covertly practised until restricted by law. The

steps employed did not actually improve the coffee by any means, but

merely put it into condition for more ready sale. An apparently sincere

endeavor to renovate damaged coffee was made by Evans[116] when he

treated it with an aqueous solution of sulphuric acid having a density

of 10.5° Baumé. After agitation in this solution, the beans were washed

free from acid and dried. In this manner discolorations and impurities

were removed and the beans given a fuller appearance.

The addition of glucose, sucrose, lactose, or dextrin to green coffees

is practised by von Niessen[117] and by Winter[118], with the object of

giving a mild taste and strong aroma to "hard" coffees. The addition is

accomplished by impregnating, with or without the aid of vacuum, the

beans with a moderately concentrated solution of the sugar, the liquid

being of insufficient quantity to effect extraction. When the solution

has completely disseminated through the kernels, they are removed and

dried. Upon subsequent roasting, a decided amelioration of flavor is

secured.

Another method developed by von Niessen[119] comprises the softening of

the outer layers of the beans by steam, cold or warm water, or brine,

and then surrounding them with an absorbent paste or powder, such as

china clay, to which a neutralizing agent such as magnesium oxid may be

added. After drying, the clay can be removed by brushing or by causing

the beans to travel between oppositely reciprocated wet cloths. In the

development of this process, von Niessen evidently argued that the

so-called "caffetannic acid" is the "harmful" substance in coffee, and

that it is concentrated in the outer layers of the coffee beans. If

these be his precepts, the question of their correctness and of the

efficiency of his process becomes a moot one.

A procedure which aims at cleaning and refining raw coffee, and which

has been the subject of much polemical discussion, is that of Thum[120].

It entails the placing of the green beans in a perforated drum; just

covering them with water, or a solution of sodium chloride or sodium

carbonate, at 65° to 70° C.; and subjecting them to a vigorous brushing

for from 1 to 5 minutes, according to the grade of coffee being treated.

The value of this method is somewhat doubtful, as it would not seem to

accomplish any more than simple washing. In fact, if anything, the

process is undesirable; as some of the extractive matters present in the

coffee, and particularly caffein, will be lost. Both Freund[121] and

Harnack[122] hold briefs for the product produced by this method, and

the latter endeavors analytically to prove its merits; but as his

experimental data are questionable, his conclusions do not carry much

weight.

_The Acids of Coffee_

The study of the acids of coffee has been productive of much controversy

and many contradictory results, few of which possess any value. The acid

of coffee is generally spoken of as "caffetannic acid." Quite a few

attempts have been made to determine the composition and structure of

this compound and to assign it a formula. Among them may be noted those

of Allen,[123] who gives it the empirical formula C_14_H_16_O_7;

Hlasiwetz,[124] who represents it as C_15_H_18_O_8; Richter, as

C_30_H_18_O_16; Griebel,[125] as C_18_H_24_O_10, and Cazeneuve

and Haddon,[126] as C_21_H_28_O_14. It is variously supposed to

exist in coffee as the potassium, calcium, or magnesium salt. In regard

to the physical appearance of the isolated substance there is also some

doubt, Thorpe[127] describing it as an amorphous powder, and Howard[128]

as a brownish, syrup-like mass, having a slight acid and astringent

taste.

The chemical reactions of "caffetannic acid" are generally agreed upon.

A dark green coloration is given with ferric chloride; and upon boiling

it with alkalies or dilute acids, caffeic acid and glucose are formed.

Fusion with alkali produces protocatechuic acid.

K. Gorter[129] has made an extensive and accurate investigation into the

matter, and in reporting upon the same has made some very pertinent

observations. His claim is that the name "caffetannic acid" is a

misnomer and should be abandoned. The so-called "caffetannic acid" is

really a mixture which has among its constituents chlorogenic acid

(C_32_H_38_O_19), which is not a tannic acid, and coffalic acid.

Tatlock and Thompson[130] have expressed the opinion that roasted coffee

contains no tannin, and that the lead precipitate contains mostly

coloring matter. They found only 4.5 percent of tannin (precipitable by

gelatin or alkaloids) in raw coffee.

Hanausek[131] demonstrated the presence of oxalic acid in unripe beans,

and citric acid has been isolated from Liberian coffee. It also has been

claimed that viridic acid, C_14_H_20_O_11, is present in coffee. In

addition to these, the fat of coffee contains a certain percentage of

free fatty acids.

It is thus apparent that even in green coffee there is no definite

compound "caffetannic acid," and there is even less likelihood of its

being present in roasted coffee. The conditions, high heat and

oxidation, to which coffee is subjected in roasting would suffice to

decompose this hypothetical acid if it were present.

In the method of analysis for caffetannic acid (No. 24) given at the end

of this chapter, there are many chances of error, although this

procedure is the best yet devised. Lead acetate forms three different

compounds with "caffetannic acid," so that this reagent must be added

with extreme care in order to precipitate the compound desired. The

precipitate, upon forming, mechanically carries down with it any fats

which may be present, and which are removed from it only with

difficulty. The majority of the mineral salts in the solution will come

down simultaneously. All of the above-mentioned organic acids form

insoluble salts with lead acetate, and there will also be a tendency

toward precipitation of certain of the components of caramel, the acidic

polymerization products of acrolein, glycerol, etc., and of the proteins

and their decomposition products.

In view of this condition of uncertainty in composition, necessity for

great care in manipulation, and ever-present danger of contamination,

the significance of "caffetannic acid analysis" fades. It is highly

desirable that the nomenclature relevant to this analytical procedure be

changed to one, such as "lead number," which will be more truly

indicative of its significance.

_The Alkaloids of Coffee_

In addition to caffein, the main alkaloid of coffee, trigonellin--the

methylbetaine of nicotinic acid--sometimes known as caffearine, has been

isolated from coffee.[132] This alkaloid, having the formula

C_14_H_16_O_4_N_2, is also found in fenugreek, _Trigonella

foenum-græcum_, in various leguminous plants, and in the seeds of

strophanthus. When pure it forms colorless needles melting at 140° C.,

and, as with all alkaloids, gives a weak basic reaction. It is very

soluble in water, slightly soluble in alcohol, and only very slightly

soluble in ether, chloroform or benzol, so that it does not contaminate

the caffein in the determination of the latter. Its effects on the body

have not been studied, but they are probably not very great, as

Polstorff obtained only 0.23 percent from the coffee which he examined.

Caffein, thein, trimethylxanthin, or C_5_H(CH_3)_3_N_4_O_2, in

addition to being in the coffee bean is also found in guarana leaves,

the kola nut, maté, or Paraguay tea, and, in small quantities, in cocoa.

It is also found in other parts of these plants besides those commonly

used for food purposes.

A neat test for detecting the presence of caffein is that of A.

Viehoever,[133] in which the caffein is sublimed directly from the plant

tissue in a special apparatus. The presence of caffein in the sublimate

is verified by observing its melting point, determined on a special

heating stage used in connection with a microscope.

The chief commercial source of this alkaloid is waste and damaged tea,

from which it is prepared by extraction with boiling water, the tannin

precipitated from the solution with litharge, and the solution then

concentrated to crystallize out the caffein. It is further purified by

sublimation or recrystallization from water. Coffee chaff and

roaster-flue dust have been proposed as sources for medicinal caffein,

but the extraction of the alkaloid from the former has not proven to be

a commercial success. Several manufacturers of pharmaceuticals are now

extracting caffein from roaster-flue dust, probably by an adaptation of

the Faunce[134] process. The recovery of caffein from roaster-flue gases

may be facilitated and increased by the use of a condenser such as

proposed Ewé.[135]

Pure caffein forms long, white, silky, flexible needles, which readily

felt together to form light, fleecy masses. It melts at 235-7° C. and

sublimes completely at 178° C., though the sublimation starts at 120°.

Salts of an unstable nature are formed with caffein by most acids. The

solubility of caffein as determined by Seidell[136] is given in Table I.

TABLE I--THE SOLUBILITY OF CAFFEIN

Solubility:

Grm. Caffein

per 100

Grm. of Sp. Gr. of

Sp. Gr. of Temperature Saturated Saturated

Solvent Solvent of Solution Solution Solution

Water 0.997 25 2.14

Ether 0.716 25 0.27

Chloroform 1.476 25 11.0

Acetone 0.809 30-1 2.18 0.832

Benzene 0.872 30-1 1.22 0.875

Benzaldehyde 1.055 30-1 11.62 1.087

Amylacetate 0.860 30-1 0.72 0.862

Aniline 1.02 30-1 22.89 1.080

Amyl alcohol 0.814 25 0.49 0.810

Acetic acid 1.055 21.5 2.44

Xylene 0.847 32.5 1.11 0.847

Toluene 0.862 25 0.57 0.861

The similarity between caffein and theobromin (the chief alkaloid of

cocoa), xanthin (one of the constituents of meat), and uric acid, is

shown by the accompanying structural formulæ.

These formulæ show merely the relative position occupied by caffein in

the purin group, and do not in any wise indicate, because of its

similarity of structure to the other compounds, that it has the same

physiological action. The presence and position of the methyl groups

(CH_3) in caffein is probably the controlling factor which makes its

action differ from the behavior of other members of the series. The

structure of these compounds was established, and their syntheses

accomplished, in the course of various classic researches by Emil

Fischer.[137]

[Illustration: FORMULA FOR CAFFEIN, SHOWING ITS RELATION TO THE PURIN

GROUP]

Gorter states that caffein exists in coffee in combination with

chlorogenic acid as a potassium chlorogenate, C_32_H_36_O_19,

K_2(C_8_H_10_O_2_N_4)_2·2H_2_O, which he isolated in colorless

prisms. This compound is water-soluble, but caffein can not be extracted

from the crystals with anhydrous solvents. To this behavior can probably

be attributed the difficulty experienced in extracting caffein from

coffee with dry organic solvents. However, the fact that a small

percentage can be extracted from the green bean in this manner indicates

that some of the caffein content exists therein in a free state. This

acid compound of caffein will be largely decomposed during the process

of torrefaction, so that in roasted coffee a larger percentage will be

present in the free state. Microscopical examination of the roasted bean

lends verisimilitude to this contention.

[Illustration: PLANTER'S BUNGALOW WITH COFFEE TREES IN FLOWER, MYSORE]

[Illustration: COOLIES BAGGING COFFEE ON THE DRYING GROUNDS]

[Illustration: COFFEE SCENES IN BRITISH INDIA]

TABLE II--COFFEE ANALYSES

Santos Green

| Santos Roasted

| | Padang Green

| | | Padang Roasted

| | | | Guatemala Green

| | | | | Guatemala Roasted

| | | | | | Mocha Green

| | | | | | | Mocha

| | | | | | | Roasted

| | | | | | | |

Moisture 8.75 3.75 8.78 2.72 9.59 3.40 9.06 3.36

April 20th

Moisture

September 20th 8.12 6.45 8.05 6.03 8.68 6.92 8.15 7.10

Ash 4.41 4.49 4.23 4.70 3.93 4.48 4.20 4.43

Oil 12.96 13.76 12.28 13.33 12.42 13.07 14.04 14.18

Caffein 1.87 1.81 1.56 1.47 1.26 1.22 1.31 1.28

Caffein,

dry basis 2.03 .... 1.69 .... 1.39 .... 1.44 ....

Crude fiber 20.70 14.75 21.92 14.95 22.23 15.23 22.46 15.41

Protein 9.50 12.93 12.62 14.75 10.43 11.69 8.56 9.57

Protein,

dry basis 10.41 .... 13.68 .... 11.53 .... 9.41 ....

Water extract 31.11 30.30 30.83 30.21 31.04 30.47 31.27 30.44

Specific

gravity,

10 percent

extract 1.0109 1.0101 1.0107 1.0104 1.0105 1.0104 1.0108 1.0108

Bushelweight 47.0 28.2 45.2 27.8 52.2 27.2 48.8 30.2

1,000 kernel

weight 130.60 120.20 167.30 151.35 189.20 165.80 119.52 100.00

1,000 kernel

weight,

dry basis 119.1 115.7 154.1 147.2 171.0 160.1 108.6 96.6

Dextrose .... 0.72 .... 0.81 .... 0.54 .... 0.46

Caffetannic

acid 15.58 17.44 15.37 16.93 16.27 17.13 15.61 16.89

Acidity by

titration

apparent 1.50 2.08 1.47 2.00 1.39 2.13 1.11 1.87

As may be seen in Table II,[138] the caffein content of coffee varies

with the different kinds, a fair average of the caffein content being

about 1.5 percent for _C. arabica_, to which class most of our coffees

belong. However, aside from these may be mentioned _C. canephora_, which

yields 1.97 percent caffein; _C. mauritiana_, which contains 0.07

percent of the alkaloid (less than the average "caffein-free coffee");

and _C. humboltiana_, which contains no caffein, but a bitter principle,

cafemarin. Neither do the berries of _C. Gallienii_, _C. Bonnieri_, or

_C. Mogeneti_ contain any caffein; and there has also been reported[139]

a "Congo coffee" which contained no crystallizable alkaloid whatever.

Apparently the variation in caffein content is largely due to the genus

of the tree from which the berry comes, but it is also quite probable

that the nature of the soil and climatic conditions play an important

part. In the light of what has been accomplished in the field of

agricultural research, it does not seem improbable that a man of

Burbank's ability and foresight could successfully develop a series of

coffees possessed of all the cup qualities inherent in those now used,

but totally devoid of caffein. Whether this is desirable or not is a

question to be considered in an entirely different light from the

possibility of its accomplishment.

TABLE III--CAFFEIN IN DIFFERENT ROASTS

Rio Santos Guatemala

Green 1.68% 1.85% 1.82%

Cinnamon 1.70 1.72 1.80

Medium 1.66 1.66 1.56

City 1.36 1.66 1.46

The variation in the caffein content of coffee at different intensities

of roasting, as shown in Table III[140] is, of course, primarily

dependent upon the original content of the green. A considerable portion

of the caffein is sublimed off during roasting, thus decreasing the

amount in the bean. The higher the roast is carried, the greater the

shrinkage; but, as the analyses in the above table show, the loss of

caffein proceeds out of proportion to the shrinkage, for the percentage

of caffein constantly decreases with the increase in color. If the roast

be carried almost to the point of carbonization, as in the case of the

"Italian roast," the caffein content will be almost nil. This is not a

suitable coffee for one desiring an almost caffein-free drink, for the

empyreumatic products produced by this excessive roasting will be more

toxic by far than the caffein itself would have been.

_Caffein-free Coffee_

The demand for a caffein-free coffee may be attributed to two causes,

namely: the objectionable effect which caffein has upon neurasthenics;

and the questionable advertising of the "coffee-substitute" dealers, who

have by this means persuaded many normal persons into believing that

they are decidedly sub-normal. As a result of this demand, a variety of

decaffeinated coffees have been placed on the market. Just why the

coffee men have not taken advantage of naturally caffein-free coffees,

or of the possibility of obtaining coffees low in caffein content by

chemical selection from the lines now used, is a difficult question to

answer.

In the endeavor to develop a commercial decaffeinated coffee the first

method of procedure was to extract the caffein from roasted coffee. This

method had its advantages and its disadvantages, of which the latter

predominated. The caffein in the roasted coffee is not as tightly bound

chemically as in the green coffee, and is, therefore, more easily

extracted. Also, the structure of the roasted bean renders it more

readily penetrable by solvents than does that of the green bean.

However, the great objection to this method arises from the fact that at

the same time as the caffein is extracted, the volatile aromatic and

flavoring constituents of the coffee are removed also. These substances,

which are essential for the maintenance of quality by the coffee, though

readily separated from the caffein, can not be returned to the roasted

bean with any degree of certainty. This virtually insurmountable

obstacle forced the abandonment of this mode of attack.

In order to avoid this action, the attention of investigators was

directed to extraction of the alkaloid in question from the green bean.

Because of the difficulty of causing the solvent to penetrate the bean,

recourse to grinding resulted. This greatly facilitated the desired

extraction, but a difficulty was encountered when the subsequent

roasting was attempted. The irregular and broken character of the ground

green beans resisted all attempts to produce practically a uniformly

roasted, highly aromatic product from the ground material.

Avoidance of this lack of uniformity in the product, and the great

desirability to duplicate the normal bean as far as possible,

necessitated the development of a method of extraction of the caffein

from the whole raw bean without a permanent alteration of the shape

thereof. The close structure of the green bean, and its consequent

resistance to penetration by solvents, and the existence of the caffein

in the bean as an acid salt, which is not easily soluble, offered

resistance to successful extraction.

As a means of overcoming the difficulty of structure, the beans were

allowed to stand in water in order to swell, or the cells were expanded

by treatment with steam, or the beans were subjected to the action of

some "cellulose-softening acids," such as acetic acid or sulphur dioxid.

As a method of facilitating the mechanical side of extraction without

deleterious effects, the treatment of the coffee with steam under

pressure, as utilized in the patented process of Myer, Roselius, and

Wimmer,[141] is probably the safest.

Many ingenious methods have been devised for the ready removal of the

caffein from this point on. Several processes employ an alkali, such as

ammonium hydroxid, to free the caffein from the acid; or an acid, such

as acetic, hydrochloric, or sulphurous, is used to form a more soluble

salt of caffein. Other procedures effect the dissociation of the

caffein-acid salt by dampening or immersion in a liquid and subjecting

the mass to the action of an electric current.

The caffein is usually extracted from the beans by benzol or chloroform,

but a variety of solvents may be employed, such as petrolic ether,

water, alcohol, carbon tetrachloride, ethylene chloride, acetone, ethyl

ether, or mixtures or emulsions of these. After extraction, the beans

may be steam distilled to remove and to recover any residual traces of

solvent, and then dried and roasted. It is said[142] that by heating the

beans before bringing them into contact with steam, not only is an

economy of steam effected, but the quality of the resultant product is

improved.

One clever but expensive method[143] of preparing caffein-free coffee

consists in heating the beans under pressure, with some substance, such

as sodium salicylate, with the resultant formation of a more soluble and

more easily steam-distillable compound of caffein. The beans are then

steam distilled to remove the caffein, dried, and roasted.

Another process of peculiar interest is that of Hubner,[144] in which

the coffee beans are well washed and then spread in layers and kept

covered with water at 15° C. until limited germination has taken place,

whereupon the beans are removed and the caffein extracted with water at

50° C. It is claimed by the inventor that sprouting serves to remove

some of the caffein, but it is quite probable that the process does

nothing more than accomplish simple aqueous extraction.

In the majority of these processes the flavor of the resultant product

should be very similar to natural roasted coffee. However, in the cases

where aqueous extraction is employed, other substances besides caffein

are removed that are replaced in the bean only with difficulty. The

resultant product accordingly is very likely to have a flavor not

entirely natural. On the other hand, beans from which the caffein is

extracted with volatile solvents, if the operation be conducted

carefully, should give a natural-tasting roast. Any residual traces of

the solvent left in the bean are volatilized upon roasting.

Some of the caffein-free coffees on the market show upon analysis almost

as much caffein as the natural bean. Those manufactured by reliable

concerns, however, are virtually caffein-free, their content of the

alkaloid varying from 0.3 to 0.07 percent as opposed to 1.5 percent in

the untreated coffee. Thus, although actually only caffein-poor, in

order to get the reaction of one cup of ordinary coffee one would have

to drink an unusual amount of the brew made from these coffees.

_The Aromatic Principles of Coffee_

To ascertain just what substance or substances give the pleasing and

characteristic aroma to coffee has long been the great desire of both

practical and scientific men interested in the coffee business. This

elusive material has been variously called caffeol, caffeone, "the

essential oil of coffee," etc., the terms having acquired an ambiguous

and incorrect significance. It is now generally agreed that the aromatic

constituent of coffee is not an essential oil, but a complex of

compounds which usage has caused to be collectively called "caffeol."

These substances are not present in the green bean, but are produced

during the process of roasting. Attempts at identification and location

of origin have been numerous; and although not conclusive, still have

not proven entirely futile. One of the first observations along this

line was that of Benjamin Thompson in 1812. "This fragrance of coffee is

certainly owing to the escape of a volatile aromatic substance which did

not originally exist as such in the grain, but which is formed in the

process of roasting it." Later, Graham, Stenhouse, and Campbell started

on the way to the identification of this aroma by noting that "in common

with all the valuable constituents of coffee, caffeone is found to come

from the soluble portion of the roasted seed."[145]

Comparison of the aroma given off by coffee during the roasting process

with that of fresh-ground roasted coffee shows that the two aromas,

although somewhat different, may be attributed to the same substances

present in different proportions in the two cases. Recovery and

identification of the aromatic principles escaping from the roaster

would go far toward answering the question regarding the nature of the

aroma. Bernheimer[146] reported water, caffein, caffeol, acetic acid,

quinol, methylamin, acetone, fatty acids and pyrrol in the distillate

coming from roasting coffee. The caffeol obtained by Bernheimer in this

work was believed by him to be a methyl derivative of saligenin.

Jaeckle[147] examined a similar product and found considerable

quantities of caffein, furfurol, and acetic acid, together with small

amounts of acetone, ammonia, trimethylamin, and formic acid. The caffeol

of Bernheimer could not be detected. Another substance was separated

also, but in too small a quantity to permit complete identification.

This substance consisted of colorless crystals, which readily sublimed,

melted at 115° to 117° C., and contained sulphur. The crystals were

insoluble in water, almost insoluble in alcohol, but readily soluble in

ether.

By distilling roasted coffee with superheated steam, Erdmann[148]

obtained an oil consisting of an indifferent portion of 58 percent and

an acid portion of 42 percent, consisting mainly of a valeric acid,

probably alphamethylbutyric acid. The indifferent portion was found to

contain about 50 percent furfuryl alcohol, together with a number of

phenols. The fraction containing the characteristic odorous constituent

of coffee boiled at 93° C. under 13 mm. pressure. The yield of this

latter principle was extremely small, only about 0.89 gram being

procured from 65 kilos of coffee.

Pyridin was also shown to be present in coffee by Betrand and

Weisweiller[149] and by Sayre.[150] As high as 200 to 500 milligrams of

this toxic compound have been obtained from 1 kilogram of freshly

roasted coffee.

As stated above, the empyreumatic volatile aromatic constituents of the

coffee are without question formed during and by the roasting process.

According to Thorpe,[151] the most favorable temperature for development

of coffee odor and flavor is about 200° C. Erdmann claimed to have

produced caffeol by gently heating together caffetannic acid, caffein,

and cane sugar. Other investigators have been unable to duplicate this

work. Another authority,[152] giving it the empirical formula

C_8_H_10_O_2, states that it is produced during roasting, probably

at the expense of a portion of the caffein. These conceptions are in the

main incomplete and inaccurate.

By means of careful work, Grafe[153] came closer to ascertaining the

origin of the fugacious aromatic materials. His work with normal,

caffein-free coffee and with Thum's purified coffee led him to state

that a part of these substances was derived from the crude fiber,

probably from the hemi-cellulose of the thick endosperm cells.

Sayre[154] makes the most plausible proposal regarding the origin of

caffeol. He considers the roasting of coffee as a destructive

distillation process, summarizing the results, briefly, as the

production of furfuraldehyde from the carbohydrates, acrolein from the

fats, catechol and pyrogallol from the tannins, and ammonia, amins, and

pyrrols from the proteins. The products of roasting inter-react to

produce many compounds of varying degrees of complexity and toxicity.

The great difficulty which arises in the attempt to identify the

aromatic constituents of coffee is that the caffeols of no two coffees

may be said to be the same. The reason for this is apparent; for the

green coffees themselves vary in composition, and those of the same

constitution are not roasted under identical conditions. Therefore, it

is not to be expected that the decomposition products formed by the

action of the different greens would be the same. Also, these volatile

products occur in the roasted coffee in such a small amount that the

ascertaining of their percentage relationship and the recognition of all

that are present are not possible with the methods of analysis at

present at our disposal. Until better analytical procedures have been

developed we can not hope to establish a chemical basis for the grading

of coffees from this standpoint.

_Coffee Oil and Fat_

It is well to distinguish between the "coffee oils," as they are termed

by the trade, and true coffee oil. In speaking of the qualities of

coffee, connoisseurs frequently use erroneous terms, particularly when

they designate certain of the flavoring and aromatic constituents of

coffee as "oils" or "essential oils." Coffee does not contain any

essential oils, the aromatic constituent corresponding to essential oil

in coffee being caffeol, a complex which is water-soluble, a property

not possessed by any true oil. True, the oil when isolated from roasted

coffee does possess, before purification, considerable of the aromatic

and flavoring constituents of coffee. They are, however, no part of the

coffee fat, but are held in it no doubt by an enfleurage action in much

the same way that perfumes of roses, etc., are absorbed and retained by

fats and oils in the commercial preparation of pomades and perfumes.

This affinity of the coffee oil for caffeol assists in the retention of

aromatic substances by the whole roasted bean. However, upon extraction

of ground roasted coffee with water, the caffeol shows a preferential

solubility in water, and is dissolved out from the oil, going into the

brew.

The true oil of coffee has been investigated to a fair degree and has

been found to be inodorous when purified. Analysis of green and roasted

coffees shows them to possess between 12 percent and 20 percent fat.

Warnier[155] extracted ground unroasted coffee with petroleum ether,

washed the extract with water, and distilled off the solvent, obtaining

a yellow-brownish oil possessing a sharp taste. From his examination of

this oil he reported these constants: d_24-5, 0.942; refraction at

25°, 81.5; solidifying point, 6° to 5°; melting point, 8° to 9°;

saponification number, 177.5; esterification number, 166.7; acid number,

6.2; acetyl number, 0; iodin number, 84.5 to 86.3. Meyer and Eckert[156]

carefully purified coffee oil and saponified it with Li_2_O in alcohol.

In the saponifiable portion, glycerol was the only alcohol present, the

acids being carnaubic, 10 percent; daturinic acid, 1 to 1.5 percent;

palmitic acid, 25 to 28 percent; capric acid, 0.5 percent; oleic acid,

2 percent, and linoleic acid, 50 percent. The unsaponifiable wax

amounted to 21.2 percent, was nitrogen-free, gave a phytostearin

reaction, and saponification and oxidation indicated that it was

probably a tannol carnaubate. Von-Bitto[157] examined the fat extracted

from the inner husk of the coffee berry and found it to be faint yellow

in color, and to solidify only gradually after melting. Upon analysis,

it showed: saponification value, 141.2; palmitic acid, 37.84 percent,

and glycerids as tripalmitin, 28.03 percent.

_Carbohydrates of the Coffee Berry_

There has been considerable diversity of opinion regarding the sugar of

coffee. Bell believed the sugar to be of a peculiar species allied to

melezitose, but Ewell,[158] G.L. Spencer, and others definitely proved

the presence of sucrose in coffee. In fat-free coffee 6 percent of

sucrose was found extractable by 70 percent alcohol. Baker[159] claimed

that manno-arabinose, or manno-xylose, formed one of the most important

constituents of the coffee-berry substance and yielded mannose on

hydrolysis. Schultze and Maxwell state that raw coffee contains

galactan, mannan, and pentosans, the latter present to the extent of 5

percent in raw and 3 percent in roasted coffee. By distilling coffee

with hydrochloric acid Ewell obtained furfurol equivalent to 9 percent

pentose. He also obtained a gummy substance which, on hydrolysis, gave

rise to a reducing sugar; and as it gave mucic acid and furfurol on

oxidation, he concluded that it was a compound of pentose and galactose.

In undressed Mysore coffee Commaille[160] found 2.6 percent of glucose

and no dextrin. This claim of the presence of glucose in coffee was

substantiated by the work of Hlasiwetz,[161] who resolved a caffetannic

acid, which he had isolated, into glucose and a peculiar crystallizable

acid, C_8_H_8_O_4, which he named caffeic acid.

The starch content of coffee is very low. Cereals may readily be

detected and identified in coffee mixtures by the presence and

characteristics of their starch, in view of the fact that coffee

(chicory, too) is practically free from starch. On this score it is

inadvisable for diabetics to use any of the many cereal substitutes for

coffee. It is pertinent to note in this connection that persons

suffering from diabetes may sweeten their coffee with saccharin (1/2 to

1 grain per cup) or glycerol, thus obtaining perfect satisfaction

without endangering their health.

The cellulose in coffee is of a very hard and horny character in the

green bean, but it is made softer and more brittle during the process of

roasting. It is rather difficult to define under the microscope,

particularly after roasting, even though the chief characteristics of

the cellular tissue are more or less retained. Coffee cellulose gives a

blue color with sulphuric acid and iodin, and is dissolved by an

ammoniacal solution of copper oxid. Even after roasting, remnants of the

silver skin are always present, the structure of which, a thin membrane

with adherent, thick-walled, spindle-shaped, hollow cells, is peculiar

to coffee.

_The Chemistry of Roasting_

The effect of the heat in the roasting of coffee is largely evidenced as

a destructive distillation and also as a partial dehydration. At the

same time, oxidizing and reducing reactions probably occur within the

bean, as well as some polymerization and inter-reactions.

A loss of water is to be expected as the natural outcome of the

application of heat; and analyses show that the moisture content of raw

coffee varies from 8 to 14 percent, while after roasting it rarely

exceeds 3 percent, and frequently falls as low as 0.5 percent. The loss

of the original water content of the green bean is not the only moisture

loss; for many of the constituents of coffee, notably the carbohydrates,

are decomposed upon heating to give off water, so that analysis before

and after roasting is no direct indication of the exact amount of water

driven off in the process. If it be desired to ascertain this quantity

accurately, catching of the products which are driven off and

determination of their water content becomes necessary.

The carbohydrates both dehydrate and decompose. The result of the

dehydration is the formation of caramel and related products, which

comprise the principal coloring matters in coffee infusion. That portion

of the carbohydrates known as pentosans gives rise to furfuraldehyde,

one of the important components of caffeol.

The effect of roasting upon the fat content of the beans is to reduce

its actual weight, but not to change appreciably the percentage

present, since the decrease in quantity keeps pace fairly well with the

shrinkage. Some of the more volatile fatty acids are driven off, and the

fats break down to give a larger percentage of free fatty acids, some

light esters, acrolein, and formic acid. If the roast be a very heavy

one, or is brought up too rapidly, the fat will come to the surface,

through breaking of the fat cells, with a decided alteration in the

chemical nature of the fat and with pronounced expansion and cracking.

Decomposition of the caffein acid-salt and considerable sublimation of

the caffein also occur. The majority of the caffein undergoes this

volatilization unchanged, but a portion of it is probably oxidized with

the formation of ammonia, methylamin, di-methylparabanic acid, and

carbon dioxid. This reaction partly explains why the amount of caffein

recovered from the roaster flues is not commensurate with the amount

lost from the roasting coffee; although incomplete condensation is also

an important factor. Microscopic examination of the roasted beans will

show occasional small crystals of caffein in the indentations on the

surface, where they have been deposited during the cooling process.

The compound, or compounds, known as "caffetannic acid" are probably the

source of catechol, as the proteins are of ammonia, amins, and pyrrols.

The crude fiber and other unnamed constituents of the raw beans react

analogously to similar compounds in the destructive distillation of

wood, giving rise to acetone, various fatty acids, carbon dioxid and

other uncondensable gases, and many compounds of unknown identity.

During the course of roasting and subsequent cooling these decomposition

products probably interact and polymerize to form aromatic tar-like

materials and other complexes which play an important rôle among the

delicate flavors of coffee. In fact, it is not unlikely that these

reactions continue throughout the storage time after roasting, and that

upon them the deterioration of roasted coffee is largely dependent.

Speculation upon what complex compounds are thus formed offers much

attraction. A notable one by Sayre[162] postulates the reaction between

acrolein and ammonia to give methyl pyridin, which in turn with furfurol

forms furfurol vinyl pyridin. This upon reduction would produce the

alkaloid, conin, traces of which have been found in coffee.

Although furfuraldehyde is the natural decomposition product of

pentosans, furfuryl alcohol is the main furane body of coffee aroma.

This would indicate that active reducing conditions prevail within the

bean during roasting; and the further fact that carbon monoxid is given

off during roasting makes this seem quite probable. If one admits that

caffetannic acid exists in the green bean; that upon oxidation it gives

viridic acid; and that it is concentrated in the outer layers of the

bean, as certain investigators have claimed, then there is chemical

proof of the existence of oxidizing conditions about the exterior of the

bean. In any event, however, the fact that oxidizing conditions

predominate on the external portion of the bean is obvious. Accordingly,

our meager knowledge of the chemistry of roasting indicates that while

the external layers of the roasting beans are subjected to oxidizing

conditions, reducing ones exist in the interior. Future experimentation

will, no doubt, prove this to be the case.

Attempts have been made to retain in the beans the volatile products,

which normally escape, both by coating previous to roasting[163] and by

conducting the process under pressure.[164] However, the results so

obtained were not practical, since the cup values were decreased in the

majority of cases, and the physiological effects produced were

undesirable. In cases where the quality was improved, the gain was not

sufficient to recompense the roaster for the additional expense and

difficulty of operation.

Various persons have essayed to control the roasting process

automatically; but the extreme variance in composition of different

coffees, the effect of changing atmospheric conditions, and the lack of

constancy in the calorific power of fuels have conspired to defeat the

automatic roasting machine.[165] It is even doubtful whether De

Mattia's[166] process for roasting until the vapors evolved produce a

violet color when passed into a solution of fuchsin decolorized with

sulphur dioxid is commercially reliable.

Many patents have been granted for the treatment of coffees immediately

prior to or during roasting with the object of thus improving the

product. The majority of these depend upon adding solutions of

sugar,[167] calcium saccharate,[168] or other carbohydrates,[169] and in

the case of Eckhardt,[170] of small percentages of tannic acid and fat.

In direct opposition to this latter practise, Jurgens and Westphal[171]

apply alkali, ostensibly to lessen the "tannic acid" content.

Brougier[172] sprays a solution containing caffein upon the roasting

berries; and Potter[173] roasts the coffee together with chicory,

effecting a separation at the end.

[Illustration: GROUND COFFEE UNDER THE MICROSCOPE]

The exact effect which roasting with sugars has upon the flavor is not

well understood; but it is known that it causes the beans to absorb more

moisture, due to the hygroscopicity of the caramel formed. For instance,

berries roasted with the addition of glucose syrup hold an additional 7

percent of water and give a darker infusion than normally roasted

coffee. When the green coffee is glazed with cane sugar prior to

roasting, the losses during the process are much higher than ordinarily,

on account of the higher temperature required to attain the desired

results. Losses for ordinary coffee taken to a 16-percent roast are 9.7

percent of the original fat and 21.1 percent of the original caffein;

while for "sugar glazed" coffee the losses were 18.3 percent of the

original fat and 44.3 percent of the original caffein, using 8 to 9

percent sugar with Java coffee.

_Grinding and Packaging_

It is a curious fact that green coffee improves upon aging, whereas

after roasting it deteriorates with time. Even when packed in the best

containers, age shows to a disadvantage on the roasted bean. This is due

to a number of causes, among which are oxidation, volatilization of the

aroma, absorption of moisture and consequent hydrolysis, and alteration

in the character of the aromatic principles. Doolittle and Wright[174]

in the course of some extensive experiments found that roasted coffee

showed a continual gain in weight throughout 60 weeks, this gain being

mostly due to moisture absorption. An investigation by Gould[175] also

demonstrated that roasted coffee gives off carbon dioxid and carbon

monoxid upon standing. The latter, apparently produced during roasting

and retained by the cellular structure of the bean, diffuses therefrom;

whereas the former comes from an ante-roasting decomposition of unstable

compounds present.[176]

The surface of the whole bean forms a natural protection against

atmospheric influences, and as soon as this is broken, deterioration

sets in. On this account, coffee should be ground immediately before

extraction if maximum efficiency is to be obtained. The cells of the

beans tend to retain the fugacious aromatic principles to a certain

extent; so that the more of these which are broken in grinding, the

greater will be the initial loss and the more rapid the vitiation of the

coffee. It might, therefore, seem desirable to grind coarsely in order

to avoid this as much as possible. However, the coarser the grind, the

slower and more incomplete will be the extraction. A patent[177] has

been granted for a grind which contains about 90 percent fine coffee and

10 percent coarse, the patentee's claim being that in his "irregular

grind" the coarse coffee retains enough of the volatile constituents to

flavor the beverage, while the fine coffee gives a very high

extraction, thus giving an efficient brew without sacrificing

individuality.

In packaging roasted coffee the whole bean is naturally the best form to

employ, but if the coffee is ground first, King[178] found that

deterioration is most rapid with the coarse ground coffee, the speed

decreasing with the size of the ground particles. He explains this on

the ground of "ventilation"--the finer the grind, the closer the

particles pack together, the less the circulation of air through the

mass, and the smaller the amount of aroma which is carried away. He also

found that glass makes the best container for coffee, with the tin can,

and the foil-lined bag with an inner lining of glassine, not greatly

inferior.

Considerable publicity has been given recently to the method of packing

coffee in a sealed tin under reduced pressure. While thus packing in a

partial vacuum undoubtedly retards oxidation and precludes escape of

aroma from the original package, it would seem likely to hasten the

initial volatilizing of the aroma. Also, it would appear from

Gould's[179] work that roasted coffee evolves carbon dioxid until a

certain positive pressure is attained, regardless of the initial

pressure in the container. Accordingly, vacuum-packing apparently

enhances decomposition of certain constituents of coffee. Whether this

result is beneficial or otherwise is not quite clear.

_Brewing_

The old-time boiling method of making coffee has gone out of style,

because the average consumer is becoming aware of the fact that it does

not give a drink of maximum efficiency. Boiling the ground coffee with

water results in a large loss of aromatic principles by steam

distillation, a partial hydrolysis of insoluble portions of the grounds,

and a subsequent extraction of the products thus formed, which give a

bitter flavor to the beverage. Also, the maintenance of a high

temperature by the direct application of heat has a deleterious effect

upon the substances in solution. This is also true in the case of the

pumping percolator, and any other device wherein the solution is caused

to pass directly into steam at the point where heat is applied. Warm and

cold water extract about the same amount of material from coffee; but

with different rates of speed, an increase in temperature decreasing the

time necessary to effect the desired result.

It is a well known fact that re-warming a coffee brew has an undesirable

effect upon it. This is very probably due to the precipitation of some

of the water-soluble proteins when the solution cools, and their

subsequent decomposition when heat is applied directly to them in

reheating the solution. The absorption of air by the solution upon

cooling, with attendant oxidation, which is accentuated by the

application of heat in re-warming, must also be considered. It is

likewise probable that when an extract of coffee cools upon standing,

some of the aromatic principles separate out and are lost by

volatilization.

The method of extracting coffee which gives the most satisfaction is

practised by using a grind just coarse enough to retain the

individualistic flavoring components, retaining the ground coffee in a

fine cloth bag, as in the urn system, or on a filter paper, as in the

Tricolator, and pouring water at boiling temperature over the coffee.

During the extraction, a top should be kept on the device to minimize

volatilization, and the temperature of the extract should be maintained

constant at about 200° F. after being made. Whether a repouring is

necessary or not is dependent upon the speed with which the water passes

through the coffee, which in turn is controlled by the fineness of the

grind and of the filtering medium.

_The Water Extract_

Although many analyses of the whole coffee bean are available, but

little work has been reported upon the aqueous extracts. The total water

extract of roasted coffee varies from 20 to 31 percent in different

kinds of coffee. The following analysis of the extract from a Santos

coffee may be taken as a fair average example of the water-soluble

material.[180]

TABLE IV--ANALYSIS OF SANTOS COFFEE EXTRACT

(DRY BASIS)

Ether extract, fixed 1.06%

Total nitrogen 3.40%

Caffein 5.42%

Crude fiber 0.25%

Total ash 17.43%

Reducing sugar 2.70%

Caffetannic acid 15.33%

Protein 7.71%

It is difficult to make the trade terms, such as acidity, astringency,

etc., used in describing a cup of coffee, conform with the chemical

meanings of the same terms. However, a fair explanation of the cause of

some of these qualities can be made. Careful work by Warnier[181] showed

the actual acidities of some East India coffees to be:

TABLE V--ACIDITY OF SOME EAST INDIA COFFEES

Coffee from Acid Content

Sindjai 0.033%

Timor 0.028%

Bauthain 0.019%

Boengei 0.016%

Loewae 0.021%

Waloe Pengenten 0.018%

Kawi Redjo 0.015%

Palman Tjiasem 0.022%

Malang 0.013%

These figures may be taken as reliable examples of the true acid content

of coffee; and though they seem very low, it is not at all

incomprehensible that the acids which they indicate produce the acidity

in a cup of coffee. They probably are mainly volatile organic acids,

together with other acidic-natured products of roasting. We know that

very small quantities of acids are readily detected in fruit juices and

beer, and that variation in their percentage is quickly noticed, while

the neutralization of this small amount of acidity leaves an insipid

drink. Hence, it seems quite likely that this small acid content gives

to the coffee brew its essential acidity. A few minor experiments on

neutralization have proven that a very insipid beverage is produced by

thus treating a coffee infusion.

The body, or what might be called the licorice-like character, of

coffee, is due conceivably to the presence of bodies of a glucosidic

nature and to caramel. Astringency, or bitterness, is dependent upon the

decomposition products of crude fiber and chlorogenic acid, and upon the

soluble mineral content of the bean. The degree to which a coffee is

sweet-tasting or not is, of course, dependent upon its other

characteristics, but probably varies with the reducing sugar content.

Aside from the effects of these constituents upon cup quality, the

influence of volatile aromatic and flavoring constituents is always

evident in the cup valuation, and introduces a controlling factor in the

production of an individualistic drink.

_Coffee Extracts_

The uncertainty of the quality of coffee brews as made from day to day,

the inconvenience to the housewife of conducting the extraction, and the

inevitable trend of the human race toward labor-saving devices, have

combined their influences to produce a demand for a substance which will

give a good cup of coffee when added to water. This gave rise to a

number of concentrated liquid and solid "extracts of coffee," which,

because of their general poor quality, soon brought this type of product

into disrepute. This is not surprising; for these preparations were

mainly mixtures of caramel and carelessly prepared extracts of chicory,

roasted cereals, and cheap coffee.

Liquid extracts of coffee galore have appeared on the market only soon

to disappear. Difficulty is experienced in having them maintain their

quality over a protracted period of time, primarily due to the

hydrolyzing action of water on the dissolved substances. They also

ferment readily, although a small percentage of preservative, such as

benzoate of soda, will halt spoilage.[182]

So much trouble is not encountered with coffee-extract powders--the

so-called "soluble" or "instant" coffees. The majority of these powdered

dry extracts do, however, show great affinity for atmospheric moisture.

Their hygroscopicity necessitates packing and keeping them in air-tight

containers to prevent them running into a solid, slowly soluble mass.

The general method of procedure employed in the preparation of these

powders is to extract ground roasted coffee with water, and to evaporate

the aqueous solution to dryness with great care. The major difficulty

which seems to arise is that the heat needed to effect evaporation

changes the character of the soluble material, at the same time driving

off some volatile constituents which are essential to a natural flavor.

Many complex and clever processes have been developed for avoiding these

difficulties, and quite a number of patents on processes, and several on

the resultant product, have been allowed; but the commercial production

of a soluble coffee of freshly-brewed-coffee-duplicating-power is yet to

be accomplished. However, there are now on the market several

coffee-extract powders which dissolve readily in water, giving quite a

fair approximation of freshly brewed coffee. The improvement shown

since they first appeared augurs well for the eventual attainment of

their ultimate goal.

_Adulterants and Substitutes_

There would appear to be three reasons why substitutes for coffee are

sought--the high cost, or absence, of the real product; the acquiring of

a preferential taste, by the consumer, for the substitute; and the

injurious effects of coffee when used to excess. Makers of coffee

substitutes usually emphasize the latter reason; but many substitutes,

which are, or have been, on the market, seem to depend for their

existence on the other two. Properly speaking, there are scarcely any

real substitutes for coffee. The substances used to replace it are

mostly like it only in appearance, and barely simulate it in taste.

Besides, many of them are not used alone, but are mixed with real coffee

as adulterants.

The two main coffee substitutes are chicory and cereals. Chicory,

succory, _Cichorium Intybus_, is a perennial plant, growing to a height

of about three feet, bearing blue flowers, having a long tap root, and

possessing a foliage which is sometimes used as cattle food. The plant

is cultivated generally for the sake of its root, which is cut into

slices, kiln-dried, and then roasted in the same manner as coffee,

usually with the addition of a small proportion of some kind of fat. The

preparation and use of roasted chicory originated in Holland, about

1750. Fresh chicory[183] contains about 77 percent water, 7.5 gummy

matter, 1.1 of glucose, 4.0 of bitter extractive, 0.6 fat, 9.0

cellulose, inulin and fiber, and 0.8 ash. Pure roasted chicory[184]

contains 74.2 percent water-soluble material, comprised of 16.3 percent

water, 26.1 glucose, 9.6 dextrin and inulin, 3.2 protein, 16.4 coloring

matter, and 2.6 ash; and 25.8 percent insoluble substances, namely, 3.2

percent protein, 5.7 fat, 12.3 cellulose, and 4.6 ash. The effect of

roasting upon chicory is to drive off a large percentage of water,

increasing the reducing sugars, changing a large proportion of the

bitter extractives and inulin, and forming dextrin and caramel as well

as the characteristic chicory flavor.

The cereal substitutes contain almost every type of grain, mainly wheat,

rye, oats, buckwheat, and bran. They are prepared in two general ways,

by roasting the grains, or the mixtures of grains, with or without the

addition of such substances as sugar, molasses, tannin, citric acid,

etc., or by first making the floured grains into a dough, and then

baking, grinding, and roasting. Prior to these treatments, the grains

may be subjected to a variety of other treatments, such as impregnation

with various compounds, or germination. The effect of roasting on these

grains and other substitutes is the production of a destructive

distillation, as in the case of coffee; the crude fiber, starches, and

other carbohydrates, etc., being decomposed, with the production of a

flavor and an aroma faintly suggesting coffee.

The number, of other substitutes and imitations which have been employed

are too numerous to warrant their complete description; but it will

prove interesting to enumerate a few of the more important ones, such as

malt, starch, acorns, soya beans, beet roots, figs, prunes, date stones,

ivory nuts, sweet potatoes, beets, carrots, peas, and other vegetables,

bananas, dried pears, grape seeds, dandelion roots, rinds of citrus

fruits, lupine seeds, whey, peanuts, juniper berries, rice, the fruit of

the wax palm, cola nuts, chick peas, cassia seeds, and the seeds of any

trees and plants indigenous to the country in which the substitute is

produced.

Aside from adulteration by mixing substitutes with ground coffee, and an

occasional case of factitious molded berries, the main sophistications

of coffee comprise coating and coloring the whole beans. Coloring of

green and roasted coffees is practised to conceal damaged and inferior

beans. Lead and zinc chromates, Prussian blue, ferric oxid, coal-tar

colors, and other substances of a harmful nature, have been employed for

this purpose, being made to adhere to the beans with adhesives. As

glazes and coatings, a variety of substances have been employed, such as

butter, margarin, vegetable oils, paraffin, vaseline, gums, dextrin,

gelatin, resins, glue, milk, glycerin, salt, sodium bicarbonate,

vinegar, Irish moss, isinglass, albumen, etc. It is usually claimed that

coating is applied to retain aroma and to act as a clarifying agent; but

the real reasons are usually to increase weight through absorption of

water, to render low-grade coffees more attractive, to eliminate

by-products, and to assist in advertising.

METHODS OF ANALYSIS OF COFFEES[185]

(_Official and Tentative_)

(Sole responsibility for any errors in compilation or printing of

these methods is assumed by the author.)

GREEN COFFEE

1. _Macroscopic Examination--Tentative_

A macroscopic examination is usually sufficient to show the presence of

excessive amounts of black and blighted coffee beans, coffee hulls,

stones, and other foreign matter. These can be separated by hand-picking

and determined gravi-metrically.

2. _Coloring Matters--Tentative_

Shake vigorously 100 grams or more of the sample with cold water or 70

percent alcohol by volume. Strain through a coarse sieve and allow to

settle. Identify soluble colors in the solution and insoluble pigments

in the sediment.

ROASTED COFFEE

3. _Macroscopic Examination--Tentative_

Artificial coffee beans are apparent from their exact regularity of

form. Roasted legumes and lumps of chicory, when present in whole

roasted coffee, can be picked out and identified microscopically. In the

case of ground coffee, sprinkle some of the sample on cold water and

stir lightly. Fragments of pure coffee, if not over-roasted, will float;

while fragments of chicory, legumes, cereals, etc., will sink

immediately, chicory coloring the water a decided brown. In all cases

identify the particles that sink by microscopical examination.

4. _Preparation of Sample--Official_

Grind the sample to pass through a sieve having holes 0.5 mm. in

diameter and preserve in a tightly stoppered bottle.

5. _Moisture--Tentative_

Dry 5 grams of the sample at 105°--110°C. for 5 hours and subsequent

periods of an hour each until constant weight is obtained. The same

procedure may be used, drying _in vacuo_ at the temperature of boiling

water. In the case of whole coffee, grind rapidly to a coarse powder and

weigh at once portions for the determination without sifting and without

unnecessary exposure to the air.

6. _Soluble Solids--Tentative_

Place 4 grams of the sample in a 200-cc. flask, add water to the mark,

and allow the mass to infuse for eight hours, with occasional shaking;

let stand 16 hours longer without shaking, filter, evaporate 50 cc. of

filtrate to dryness in a flat-bottomed dish, dry at 100° C., cool and

weigh.

7. _Ash--Official_

Char a quantity of the substance, representing about 2 grams of the dry

material, and burn until free of carbon at a low heat, not to exceed

dull redness. If a carbon-free ash can not be obtained in this manner,

exhaust the charred mass with hot water, collect the insoluble residue

on a filter, burn till the ash is white or nearly so, and then add the

filtrate to the ash and evaporate to dryness. Heat to low redness, until

ash is white or grayish white, and weigh.

8. _Ash Insoluble in Acid--Official_

Boil the water-insoluble residue, obtained as directed under 9, or the

total ash obtained as directed under 7, with 25 cc. of 10-percent

hydrochloric acid (sp. gr. 1.050) for 5 minutes, collect the insoluble

matter on a Gooch crucible or an ashless filter, wash with hot water,

ignite and weigh.

9. _Soluble and Insoluble Ash--Official_

Heat 5 to 10 grams of the sample in a platinum dish of from 50 to 100

cc. capacity at 100° C. until the water is expelled, and add a few drops

of pure olive oil and heat slowly over a flame until swelling ceases.

Then place the dish in a muffle and heat at low redness until a white

ash is obtained. Add water to the ash, in the platinum dish, heat nearly

to boiling, filter through ash-free filter paper, and wash with hot

water until the combined filtrate and washings measure to about 60 cc.

Return the filter and contents to the platinum dish, carefully ignite,

cool and weigh. Compute percentages of water-insoluble ash and

water-soluble ash.

10. _Alkalinity of the Soluble Ash--Official_

Cool the filtrate from 9 and titrate with N/10 hydrochloric acid, using

methyl orange as an indicator.

Express the alkalinity in terms of the number of cc. of N/10 acid per 1

gram of the sample.

11. _Soluble Phosphoric Acid in the Ash--Official_

Acidify the solution of soluble ash, obtained in 9, with dilute nitric

acid and determine phosphoric acid (P_2_O_5). For percentages up to 5

use an aliquot corresponding to 0.4 gram of substance, for percentages

between 5 and 20 use an aliquot corresponding to 0.2 gram of substance,

and for percentages above 20 use an aliquot corresponding to 0.1 gram of

substance. Dilute to 75-100 cc., heat in a water-bath to 60°-65° C., and

for percentages below 5 add 20-25 cc. of freshly filtered molybdate

solution. For percentages between 5 and 20 add 30-35 cc. of molybdate

solution. For percentages greater than 20 add sufficient molybdate

solution to insure complete precipitation. Stir, let stand in the bath

for about 15 minutes, filter _at once_, wash once or twice with water by

decantation, using 25-30 cc. each time, agitate the precipitate

thoroughly and allow to settle; transfer to the filter and wash with

cold water until the filtrate from two fillings of the filter yields a

pink color upon the addition of phenolphthalein and one drop of the

standard alkali. Transfer the precipitate and filter to the beaker, or

precipitating vessel, dissolve the precipitate in a small excess of the

standard alkali, add a few drops of phenolphthalein solution, and

titrate with the standard acid.

12. _Insoluble Phosphoric Acid in the Ash--Official_

Determine phosphoric acid (P_2_O_5) in the Insoluble ash by the

foregoing method.

13. _Chlorides--Official_

Moisten 5 grams of the substance in a platinum dish with 20 cc. of a

5-percent solution of sodium carbonate, evaporate to dryness and ignite

as thoroughly as possible at a temperature not exceeding dull redness.

Extract with hot water, filter and wash. Return the residue to the

platinum dish and ignite to an ash; dissolve in nitric acid, and add

this solution to the water extract. Add a known volume of N/10 silver

nitrate in slight excess to the combined solutions. Stir well, filter

and wash the silver chloride precipitate thoroughly. To the filtrate and

washings add 5 cc. of a saturated solution of ferric alum and a few cc.

of nitric acid. Titrate the excess silver with N/10 ammonium or

potassium thiocyanate until a permanent light brown color appears.

Calculate the amount of chlorin.

14. _Caffein--The Fendler and Stüber Method--Tentative_

Pulverize the coffee to pass without residue through a sieve having

circular openings 1 mm. in diameter. Treat a 10-gram sample with 10

grams of 10-percent ammonium hydroxid and 200 grams of chloroform in a

glass-stoppered bottle and shake continuously by machine or hand for

one-half hour. Pour the entire contents of the bottle on a 12.5-cm.

folded filter, covering with a watch glass. Weigh 150 grams of the

filtrate into a 250-cc. flask and evaporate on the steam bath, removing

the last chloroform with a blast of air. Digest the residue with 80 cc.

of hot water for ten minutes on a steam bath with frequent shaking, and

let cool. Treat the solution with 20 cc. (for roasted coffee) or 10 cc.

(for unroasted coffee) of 1-percent potassium permanganate and let stand

for 15 minutes at room temperature. Add 2 cc. of 3-percent hydrogen

peroxid (containing 1 cc. of glacial acetic acid in 100 cc.). If the

liquid is still red or reddish, add hydrogen peroxid, 1 cc. at a time,

until the excess of potassium permanganate is destroyed. Place the flask

on the steam bath for 15 minutes, adding hydrogen peroxid in 0.5-cc.

portions until the liquid becomes no lighter in color. Cool and filter

into a separatory funnel, washing with cold water. Extract four times

with 25 cc. of chloroform. Evaporate the chloroform extract from a

weighed flask with aid of an air blast and dry at 100° C. to constant

weight (one-half hour is usually sufficient). Weigh the residue as

caffein and calculate on 7.5 grams of coffee. Test the purity of the

residue by determining nitrogen and multiplying by 3.464 to obtain

caffein.

15. _Caffein--Power-Chestnut Method--Official_

Moisten 10 grams of the finely powdered sample with alcohol, transfer to

a Soxhlet, or similar extraction apparatus, and extract with alcohol for

8 hours. (Care should be exercised to assure complete extraction.)

Transfer the extract with the aid of hot water to a porcelain dish

containing 10 grams of heavy magnesium oxid in suspension in 100 cc. of

water. (This reagent should meet the U.S.P. requirements.) Evaporate

slowly on the steam bath with frequent stirring to a dry, powdery mass.

Rub the residue with a pestle into a paste with boiling water. Transfer

with hot water to a smooth filter, cleaning the dish with a

rubber-tipped glass rod. Collect the filtrate in a liter flask marked at

250 cc. and wash with boiling water until the filtrate reaches the mark.

Add 10 cc. of 10-percent sulphuric acid and boil gently for 30 minutes

with a funnel in the neck of the flask. Cool and filter through a

moistened double paper into a separatory funnel and wash with small

portions of 0.5-percent sulphuric acid. Extract with six successive

25-cc. portions of chloroform. Wash the combined chloroform extracts in

a separatory funnel with 5 cc. of 1-percent potassium hydroxid solution.

Filter the chloroform into an Erlenmeyer flask. Wash the potassium

hydroxid with 2 portions of chloroform of 10 cc. each, adding them to

the flask together with the chloroform washings of the filter paper.

Evaporate or distil on the steam bath to a small volume (10-15 cc.),

transfer with chloroform to a tared beaker, evaporate carefully, dry for

30 minutes in a water oven, and weigh. The purity of the residue can be

tested by determining nitrogen and multiplying by the factor 3.464.

16. _Crude Fiber--Official_

Prepare solutions of sulphuric acid and sodium hydroxid of exactly

1.25-percent strength, determined by titration. Extract a quantity of

the substance representing about 2 grams of the dry material with

ordinary ether, or use residue from the determination of the ether

extract. To this residue in a 500-cc. flask add 200 cc. of boiling

1.25-percent sulphuric acid; connect the flask with a reflux condenser,

the tube of which passes only a short distance beyond the rubber stopper

into the flask, or simply cover a tall conical flask, which is well

suited for this determination, with a watch glass or short stemmed

funnel. Boil at once and continue boiling gently for thirty minutes. A

blast of air conducted into the flask may serve to reduce the frothing

of the liquid. Filter through linen, and wash with boiling water until

the washings are no longer acid; rinse the substance back into the flask

with 200 cc. of the boiling 1.25-percent solution of sodium hydroxid

free, or nearly so, of sodium carbonate; boil at once and continue

boiling gently for thirty minutes in the same manner as directed above

for the treatment with acid. Filter at once rapidly, wash with boiling

water until the washings are neutral. The last filtration may be

performed upon a Gooch crucible, a linen filter, or a tared filter

paper. If a linen filter is used, rinse the crude fiber, after washing

is completed, into a flat-bottomed platinum dish by means of a jet of

water; evaporate to dryness on a steam bath, dry to constant weight at

110° C., weigh, incinerate completely, and weigh again. The loss in

weight is considered to be crude fiber. If a tared filter paper is used,

weigh in a weighing bottle. In any case, the crude fiber after drying to

constant weight at 110° C., must be incinerated and the amount of the

ash deducted from the original weight.

17. _Starch--Tentative_

Extract 5 grams of the finely pulverized sample on a hardened filter

with five successive portions (10 cc. each) of ether, wash with small

portions of 95-percent alcohol by volume until a total of 200 cc. have

passed through, place the residue in a beaker with 50 cc. of water,

immerse the beaker in boiling water and stir constantly for 15 minutes

or until all the starch is gelatinized; cool to 55° C., add 20 cc. of

malt extract and maintain at this temperature for an hour. Heat again to

boiling for a few minutes, cool to 55° C., add 20 cc. of malt extract

and maintain at this temperature for an hour or until the residue

treated with iodin shows no blue color upon microscopic examination.

Cool, make up directly to 250 cc., and filter. Place 200 cc. of the

filtrate in a flask with 20 cc. of hydrochloric acid (sp. gr. 1.125);

connect with a reflux condenser and heat in a boiling water bath for 2.5

hours. Cool, nearly neutralize with sodium hydroxid solution, and make

up to 500 cc. Mix the solution well, pour through a dry filter and

determine the dextrose in an aliquot. Conduct a blank determination upon

the same volume of the malt extract as used upon the sample, and correct

the weight of reduced copper accordingly. The weight of the dextrose

obtained multiplied by 0.90 gives the weight of starch.

18. _Sugars--Tentative_

See original.[186]

19. _Petroleum Ether Extract--Official_

Dry 2 grams of coffee at 100° C., extract with petroleum ether (boiling

point 35° to 50° C.) for 16 hours, evaporate the solvent, dry the

residue at 100° C., cool, and weigh.

20. _Total Acidity--Tentative_

Treat 10 grams of the sample, prepared as directed under 4, with 75 cc.

of 80-percent alcohol by volume in an Erlenmeyer flask, stopper, and

allow to stand 16 hours, shaking occasionally. Filter and transfer an

aliquot of the filtrate (25 cc. in the case of green coffee, 10 cc. in

the case of roasted coffee) to a beaker, dilute to about 100 cc. with

water and titrate with N/10 alkali, using phenolphthalein as an

indicator. Express the result as the number of cc. of N/10 alkali

required to neutralize the acidity of 100 grams of the sample.

21. _Volatile Acidity--Tentative_

Into a volatile acid apparatus introduce a few glass beads, and over

these place 20 grams of the unground sample. Add 100 cc. of recently

boiled water to the sample, place a sufficient quantity of recently

boiled water in the outer flask and distil until the distillate is no

longer acid to litmus paper. Usually 100 cc. of distillate will be

collected. Titrate the distillate with N/10 alkali, using

phenolphthalein as an indicator. Express the result as the number of cc.

of N/10 alkali required to neutralize the acidity of 100 grams of the

sample.

UNOFFICIAL METHODS

22. _Protein_

Determine nitrogen in 3 grams of the sample by the Kjeldahl or Gunning

method. This gives the total nitrogen due to both the proteids and the

caffein. To obtain the protein nitrogen, subtract from the total

nitrogen the nitrogen due to caffein, obtained by direct determination

on the separated caffein or by calculation (caffein divided by 3.464

gives nitrogen). Multiply by 6.25 to obtain the amount of protein.

23. _Ten Percent Extract--McGill Method_

Weigh into a tared flask the equivalent of 10 grains of the dried

substance, add water until the contents of the flask weigh 110 grams,

connect with a reflux condenser and heat, beginning the boiling in 10 to

15 minutes. Boil for 1 hour, cool for 15 minutes, weigh again, making up

any loss by the addition of water, filter, and take the specific gravity

of the filtrate at 15° C.

According to McGill, a 10-percent extract of pure coffee has a specific

gravity of 1.00986 at 15° C., and under the same treatment chicory gives

an extract with a specific gravity of 1.02821. In mixtures of coffee and

chicory the approximate percentage of chicory may be calculated by the

following formula:

(1.02821 - sp. gr.)

Percent of chicory = 100 ------------------

0.01835

The index of refraction of the above solution may be taken with the

Zeiss immersion refractometer or with the Abbe refractometer.

With a 10-percent coffee extract, n_d 20° = 1.3377.

With a 10-percent chicory extract, n_d 20° = 1.3448.

Determinations of the solids, ash, sugar, nitrogen, etc., may be made in

the 10-percent extract, if desired.

24. _Caffetannic Acid--Krug's Method_[187]

Treat 2 grains of the coffee with 10 cc. of water and digest for 36

hours; add 25 cc. of 90-percent alcohol and digest 24 hours more,

filter, and wash with 90-percent alcohol. The filtrate contains tannin,

caffein, color, and fat. Heat the filtrate to the boiling point and add

a saturated solution of lead acetate. If this is carefully done, a

caffetannate of lead will be precipitated containing 49 percent of lead.

As soon as the precipitate has become flocculent, collect on a tared

filter, wash with 90-percent alcohol until free from lead, wash with

ether, dry and weigh. The precipitate multiplied by 0.51597 gives the

weight of the caffetannic acid.

[Illustration]

CHAPTER XVIII

PHARMACOLOGY OF THE COFFEE DRINK

_General physiological action--Effect on children--Effect on

longevity--Behavior in the alimentary régime--Place in

dietary--Action on bacteria--Use in medicine--Physiological action

of "caffetannic acid"--Of caffeol--Of caffein--Effect of caffein on

mental and motor efficiency--Conclusions_

By Charles W. Trigg

Industrial Fellow of the Mellon Institute of Industrial Research,

Pittsburgh, 1916-1920

The published information regarding the effects of coffee drinking on

the human system is so contradictory in its nature that it is hazardous

to make many generalizations about the physiological behavior of coffee.

Most of the investigations that have been conducted to date have been

characterized by incompleteness and a failure to be sufficiently

comprehensive to eliminate the element of individual idiosyncrasy from

the results obtained. Accordingly, it is possible to select statements

from literature to the effect either that coffee is an "elixir of life,"

or even a poison.

This is a deplorable state of affairs, not calculated to promote the

dissemination of accurate knowledge among the consuming public, but it

may be partly excused upon the grounds that experimental apparatus has

not always been at the level of perfection that it now occupies. Also,

to do justice to some of the able men who have interested themselves in

this problem, it should be said that some of their results were obtained

in researches, distinguished by painstaking accuracy, which have

effected the establishment of the major reactions of ingested coffee.

_The Physiological Action of Coffee_