Carbonic acid 49.20 parts
Glycerine 3.40 parts
Organic acids, chiefly succinic .65 parts
Ethers, aldehydes, furfural, fat, etc. 1.30 parts
──────
Total weight fermentation products produced 105.65 parts
_Artichokes._—The artichoke has been highly recommended for the
manufacture of alcohol. The fermentable material in the artichoke
is neither starch nor sugar, but consists of a mixture of a number
of carbohydrates of which inulin and levulin are the principal
constituents. When these carbohydrate materials are hydrolized into
sugars they produce levulose instead of dextrose. The levulose is
equally as valuable as dextrose for the production of alcohol.
Artichokes may be harvested either in the autumn or in the spring. As
they keep well during the winter, and in a few places {670} may be kept
in hot weather, they form a raw material which can be stored for a long
period and still be valuable for fermentation purposes.
Under the term “inulin” are included all the fermentable carbohydrates.
The above data show, in round numbers, 17 per cent of fermentable
matter. Theoretically, therefore, 100 pounds of artichokes would yield
approximately 8 1/2 pounds of industrial alcohol, or about 1 1/4
gallons.
_Bananas._—The banana is a crop which grows in luxurious abundance
in tropical countries, especially Guatemala and Nicaragua. The fruit
contains large quantities of starch and sugar suitable for alcohol
making. From 20 to 25 per cent of the weight of the banana consists
of fermentable material. It is evident that in the countries where
the banana grows in such luxuriance it would be a cheap source of
industrial alcohol.
_Barley and the Manufacture of Malt._—A very important cereal in
connection with the manufacture of alcohol is barley which is quite
universally employed for making malt, the malt in its turn being used
for the conversion of the starch of other cereals into sugar in their
preparation for fermentation.
Malt is made by the sprouting of barley at a low temperature (from 50°
to 60° F.) until the small roots are formed and the germ has grown to
the length of 1/2 an inch or more. The best malts are made at a low
temperature requiring from 10 to 14 days for the growth of the barley.
The barley is moistened and spread upon a floor, usually of cement, to
the depth of 1 foot or 18 inches. As the barley becomes warm by the
process of germination, it is turned from time to time and the room
is kept well ventilated and cool. It is better at this point in the
manufacture of malt to keep the temperature below 60° F. After the
sprouting has been continued as above noted for the proper length of
time, the barley is transferred to a drier, where it is subjected to
a low temperature at first and finally to a temperature not to exceed
140° or 158° F., until all the water is driven off, except 2 or 3 per
cent. Great care must be exercised in drying the barley not to raise
the temperature too high, lest the diastase which is formed be deprived
of its active qualities. The malt has a sweetish taste, the principal
portion of the starch having been converted into sugar, which is known
chemically as “maltose.” This sugar is, of course, utilized in the
fermentation for the production of alcohol. Malt is chiefly valuable,
however, not because of the amount of alcohol that may be produced
therefrom, but from the fact that in quantities of about 10 per cent
it is capable of converting the starch of the whole of the unmalted
grains, whatever their origin may be, into maltose, thus preparing the
starch for fermentation. Barley is not itself used in this country
as a source of industrial alcohol, but it is employed for producing
the highest grades of whisky, made of pure barley malt, which, after
fermentation, is distilled in a pot still, concentrated in another pot
still to the proper strength, placed in wood, and stored for a number
of years. Barley malt is too expensive a source of alcohol to justify
its use for industrial purposes. It is, however, one of the cheapest
and best methods of converting the starch of other cereals into sugar
preparatory to fermentation.
Barley has, in round numbers, about 68 per cent of fermentable matter.
The weight of a bushel of barley (48 pounds) multiplied by 0.68 gives
32 pounds of fermentable matter in a bushel of barley.
_Cassava._—Cassava is grown over a large area of the South Atlantic
and Gulf States of this country. Of all the substances which have been
mentioned, except the cereals, cassava contains the largest amount
of alcoholic or fermentable substances. The root, deprived of its
outer envelope, contains a little over 30 per cent of starch, while
the undetermined matter in the analyses is principally sugar. If this
be added to the starch, it is seen that approximately 35 per cent
of the fresh root is fermentable. This of course represents a very
high grade of cassava, the ordinary roots containing very much less
fermentable matter. If, however, it is assumed that the fermentable
matter of cassava root will average 25 per cent, this amount is much
greater than the average of the potato, or even of the sweet potato
and the yam. Twenty-five per cent is undoubtedly a low average content
of fermentable matter. In the dry root there is found nearly 72 per
cent of starch and 17 per cent of extract, principally sugar. Assuming
that 15 per cent of this is fermentable, and adding this to the 72 per
cent, it is seen that 87 per cent of the dry matter of the cassava is
fermentable. This appears to be a very high figure, but it doubtless
represents almost exactly the conditions which exist. It would be
perfectly safe to say, discounting any exceptional qualities of the
samples examined, that 80 per cent of the dry matter of the cassava
root is {671} capable of being converted into alcohol. It thus becomes
in a dry state a source of alcohol almost as valuable, pound for pound,
as rice.
Careful examinations, however, of actual conditions show that if 5 tons
per acre of roots are obtained it is an average yield. In very many
cases, where no fertilizer is used and where the roots are grown in the
ordinary manner, the yield is far less than this, while with improved
methods of agriculture it is greater. The bark of the root, has very
little fermentable matter in it. If the whole root be considered, the
percentage of starch is less than it would be for the peeled root. If
cassava yields 4 tons, or 8,000 pounds, per acre and contains 25 per
cent of fermentable matter, the total weight of fermentable matter
is 2,000 pounds, yielding approximately 1,000 pounds of 95 per cent
alcohol, or 143 gallons of 95 per cent alcohol per acre.
_Corn_ (_Indian Corn or Maize_).—The crop which at the present time is
the source of almost all of the alcohol made in the United States is
Indian corn.
The fermentable matter in Indian corn—that is, the part which is
capable of being converted into alcohol—amounts to nearly 70 per cent
of the total weight, since the unfermentable cellulose and pentosans
included in carbohydrates do not exceed 2 per cent. Inasmuch as a
bushel of Indian corn weighs 56 pounds, the total weight of fermentable
matter therein, in round numbers, is 39 pounds. The weight of the
alcohol which is produced under the best conditions is little less
than one-half of the fermentable matter. Therefore the total weight of
alcohol which would be yielded by a bushel of average Indian corn would
be, in round numbers, about 19 pounds. The weight of a gallon of 95 per
cent alcohol is nearly 7 pounds. Hence 1 bushel of corn would produce
2.7 gallons.
If the average price of Indian corn be placed, in round numbers, at 40
cents a bushel, the cost of the raw material—that is, of the Indian
corn—for manufacturing 95 per cent industrial alcohol is about 15 cents
a gallon. To this must be added the cost of manufacture, storage,
etc., which is perhaps as much more, making the estimated actual cost
of industrial alcohol of 95 per cent strength made from Indian corn
about 30 cents per gallon. If to this be added the profits of the
manufacturer and dealer, it appears that under the conditions cited,
industrial alcohol, untaxed, should be sold for about 40 cents per
gallon.
_Potatoes._—The weight of a bushel of potatoes is 60 pounds. As the
average amount of fermentable matter in potatoes grown in the United
States is 20 per cent, the total weight of fermentable matter in a
bushel of potatoes is 12 pounds, which would yield approximately 6
pounds or 3.6 quarts of alcohol.
The quantity of starch in American-grown potatoes varies from 15 to 20
per cent. Probably 18 per cent might be stated as the general average
of the best grades of potatoes.
Under the microscope the granules of potato starch have a distinctive
appearance. They appear as egg-shaped bodies on which, especially the
larger ones, various ring-like lines are seen. With a modified light
under certain conditions of observation a black cross is developed
upon the granule. It is not difficult for an expert microscopist to
distinguish potato from other forms of starch by this appearance.
The potato contains very little material which is capable of
fermentation aside from starch and sugars.
Although the potato is not sweet to the taste in a fresh state, it
contains notable quantities of sugar. This sugar is lost whenever the
potato is used for starch-making purposes, but is utilized when it is
used for the manufacture of industrial alcohol. The percentage of sugar
of all kinds in the potato rarely goes above 1 per cent. The average
quantity is probably not far from 0.35 per cent, including sugar,
reducing sugar, and dextrin, all of which are soluble in water. In the
treatment of potatoes for starch making, therefore, it may be estimated
that 0.35 per cent of fermentable matter is lost in the wash water.
_Average Composition._—The average composition of potatoes is:
Water 75.00 per cent
Starch 19.87 per cent
Sugars and dextrin .77 per cent
Fat .08 per cent
Cellulose .33 per cent
Ash 1.00 per cent
According to Maercker, the sugar content, including all forms of sugar,
varies greatly. Perfectly ripe potatoes contain generally no sugar or
only a fractional per cent. When potatoes are stored under unfavorable
conditions, large quantities of sugar may be developed, amounting to as
high as 5 per cent altogether. In general, it may be stated that the
content of sugar of all kinds will vary from 0.4 per cent to 3.4 per
cent, according to conditions. {672}
The liberal application of nitrogenous fertilizers increases the yield
per acre of tubers and of starch to a very marked extent, although the
average percentage of starch present is increased very little.
Of all the common root crops, the potatoes, including the yam and the
sweet potato, are the most valuable for the production of alcohol,
meaning by this term that they contain more fermentable matter per 100
pounds than other root crops.
While sugar beets, carrots, and parsnips contain relatively large
amounts of fermentable matter, these roots could not compete with
potatoes even if they could all be produced at the same price per 100
pounds.
A general review of all the data indicates that under the most
favorable circumstances and with potatoes which have been grown
especially for the purpose an average content of fermentable matter
of about 20 per cent may be reasonably expected. It is thus seen that
approximately 10 pounds of industrial alcohol can be made from 100
pounds of potatoes. If 60 pounds be taken as the average weight of a
bushel of potatoes, there are found therein 12 pounds of fermentable
matter, from which 6 pounds of industrial alcohol can be produced, or
6/7 of a gallon. It has also been shown that the amount of Indian
corn necessary for the production of a gallon of industrial alcohol
costs not less than 15 cents. From this it is evident that the potatoes
for alcohol making will have to be produced at a cost not to exceed
15 cents per bushel, before they can compete with Indian corn for the
manufacture of industrial alcohol.
_Rice._—Rice is not used to any great extent in this country for
making alcohol, but it is extensively used for this purpose in Japan
and some other countries, and has the largest percentage of fermentable
matter of all the cereals. The percentage of fermentable matter in
rice is nearly 78 per cent. A bushel of rice weighs, unhulled, 45
pounds, hulled, 56 pounds, and it therefore has about 34 and 43 pounds,
respectively, of fermentable matter for the unhulled and the hulled
rice. It is not probable that rice will ever be used to any extent in
this country as a source of industrial alcohol, although it is used
to a large extent in the manufacture of beverages, as for instance in
beers, which are often made partly of rice.
_Rye._—Large quantities of alcohol, chiefly in the form of alcoholic
beverages, are manufactured from rye. It is, in connection with Indian
corn, the principal source of the whiskies made in the United States.
Rye, however, is not used to any extent in this or other countries for
making industrial alcohol.
Rye contains almost as much fermentable matter as Indian corn. A
bushel of rye weighs 56 pounds. Wheat and other cereals, not mentioned
above, are not used in this country to any appreciable extent in the
manufacture of alcohol.
_Spelt._—This grain, which is botanically a variety of wheat, more
closely resembles barley. Under favorable conditions as much as 73
bushels per acre have been reported, and analyses show 70 per cent of
fermentable carbohydrates. The weight per bushel is about the same
as that of oats. It would appear that this crop might be worthy of
consideration as a profitable source of industrial alcohol.
_Sugar Beets._—The sugar beet is often used directly as a source of
alcohol. Working on a practical scale in France, it has been found that
from 10,430 tons of beets there were produced 183,624 gallons of crude
alcohol of 100 per cent strength. The beets contain 11.33 per cent of
sugar. From 220 pounds of sugar 15.64 gallons of alcohol were produced.
The weight of pure alcohol obtained is a little less than one-half the
weight of the dry fermentable matter calculated as sugar subjected to
fermentation. About 18 gallons of alcohol are produced for each ton of
sugar beets employed.
_Sweet Potatoes._—Experiments show that as much as 11,000 pounds of
sweet potatoes can be grown per acre. The average yield of sweet
potatoes, of course, is very much less. On plots to which no fertilizer
is added the yield is about 8,000 pounds of sweet potatoes per acre,
yielding in round numbers 1,900 pounds of starch. The quantity of
sugar in the 8,000 pounds is about 350 pounds, which added to the
starch, makes 2,250 pounds of fermentable matter per acre. This will
yield 1,125 pounds of industrial alcohol of 95 per cent strength,
or approximately 160 gallons per acre. The percentage of starch is
markedly greater than in the white or Irish potato. In all cases
over 20 per cent of starch was obtained in the South Carolina sweet
potatoes, and in one instance over 24 per cent. As much as 2,600 pounds
of starch were produced per acre.
In addition to starch, the sweet potato contains notable quantities of
sugar, sometimes as high as 6 per cent being present, so that the total
fermentable matter in the sweet potato may be {673} reckoned at the
minimum at 25 per cent. A bushel of sweet potatoes weighs 55 pounds,
and one-quarter of this is fermentable matter, or nearly 14 pounds.
This would yield, approximately, 7 pounds, or a little over 1 gallon of
95 per cent alcohol. It may be fairly stated, therefore, in a general
way, that a bushel of sweet potatoes will yield 1 gallon of industrial
alcohol.
Experiments have shown that the quantity of starch diminishes and the
quantity of sugar increases on storing. Further, it may be stated that
in the varieties of sweet potatoes which are most esteemed for table
use there is less starch and perhaps more sugar than stated above. The
total quantity of fermentable matter, however, does not greatly change,
although there is probably a slight loss.
«Utilization of Waste Material or By-Products.»—_Molasses._—The
utilization of the waste materials from the sugar factories and sugar
refineries for the purpose of making alcohol is a well-established
industry. The use of these sources of supply depends, of course, upon
the cost of the molasses. When the sugar has been exhausted as fully as
possible from the molasses the latter consists of a saccharine product,
containing a considerable quantity of unfermentable carbohydrate
matter, large quantities of mineral salts, and water. In molasses of
this kind there is probably not more than 50 pounds of fermentable
matter to 100 pounds of the product. Assuming that a gallon of such
molasses weighs 11 pounds, it is seen that it contains 5 1/2 pounds
of fermentable matter, yielding 2 1/4 pounds of industrial alcohol of
95 per cent strength. It requires about 3 gallons of such molasses to
make 1 gallon of industrial alcohol.
When the price of molasses delivered to the refineries falls as low
as 5 or 6 cents a gallon it may be considered a profitable source of
alcohol.
_Wood Pulp and Sawdust._—Many attempts have been made to produce
alcohol for industrial purposes from sawdust, wood pulp, or waste wood
material. The principle of the process rests upon the fact that the
woody substance is composed of cellulose and kindred matters which,
under the action of dilute acid (preferably sulphuric or sulphurous)
and heat, with or without pressure, undergo hydrolysis and are
changed into sugars. A large part of the sugar which is formed is
non-fermentable, consisting of a substance known as xylose. Another
part of the sugar produced is dextrose, made from the true cellulose
which the wood contains.
The yield of alcohol in many of the experiments which have been made
has not been very satisfactory. It is claimed, however, by some
authors that paying quantities of alcohol are secured. In Simmonsen’s
process for the manufacture of alcohol 1/2 per cent sulphuric acid
is employed and from 4 to 5 parts of the liquid heated with 1 part of
the finely comminuted wood for a quarter of an hour under a pressure
of 9 atmospheres. It is claimed by Simmonsen that he obtained a
yield of 6 quarts of alcohol from 110 pounds of air-dried shavings.
Another process which has been tried in this and other countries for
converting comminuted wood into alcohol is known as Classen’s. The
comminuted wood is heated for 15 minutes in a closed apparatus at a
temperature of from 248° to 293° F. in the presence of sulphurous acid
(fumes of burning sulphur) instead of sulphuric acid. It is claimed
by the inventor that he has made as much as 12 quarts of alcohol from
110 pounds of the air-dried shavings. There is reason to doubt the
possibility of securing such high yields in actual practice as are
claimed in the above processes. That alcohol can be made from sawdust
and wood shavings is undoubtedly true, but whether or not it can be
made profitably must be determined by actual manufacturing operations.
_Waste Products of Canneries, etc._—The principal waste materials
which may be considered in this connection are the refuse of wine
making, fruit evaporating, and canning industries, especially the waste
of factories devoted to the canning of tomatoes and Indian corn. In
addition to this, the waste fruit products themselves, which are not
utilized at all, as, for instance, the imperfect and rotten apples,
tomatoes, grapes, etc., may be favorably considered. The quantity of
waste products varies greatly in different materials.
The quantities of waste material in grapes and apples, as shown by
Lazenby, are as follows: About 25 per cent of the total weight in
grapes, with the exception of the wild grape, where it is about 60
per cent; with apples the average percentage of waste was found to be
23.8 per cent from 25 varieties. This included the waste in the core,
skin, and the defective apples caused by insects, fungi, bruises,
etc. In general it may be said that in the preparation of fruits for
{674} preserving purposes about 25 per cent of their weight is waste,
and this, it is evident, could be utilized for the manufacture of
alcohol. If apples be taken as a type of fruits, we may assume that
the waste portions contain 10 per cent of fermentable matters, which,
however, is perhaps rather a high estimate. Five per cent of this
might be recovered as industrial alcohol. Thus, each 100 pounds of
fruit waste in the most favorable circumstances might be expected to
produce 5 pounds of industrial alcohol. The quantity of waste which
could be utilized for this purpose would hardly render it profitable
to engage in the manufacture. A smaller percentage could be expected
from the waste of the tomato, where the quantity of sugar is not so
great. In the waste of the sweet-corn factory the amount of fermentable
matter would depend largely on the care with which the grain was
removed. There is usually a considerable quantity of starchy material
left on the cobs, and this, with the natural sugars which the grown
cobs contain, might yield quite large quantities of fermentable
matter. It would not be profitable to erect distilleries simply for
the utilization of waste of this kind, but if these wastes could be
utilized in distilleries already established it might be profitable to
devote them to this purpose.
«Manufacture of Alcohol.»—The three principal steps in the manufacture
of alcohol are (1) the preparation of the mash or wort, (2) the
fermentation of the mash or wort drawn off from the mash tun, and (3)
the distillation of the dilute alcohol formed in the beer or wash from
the fermentation tanks. The preparation of the mash includes (1) the
treatment of the material used with hot water to form a paste of the
starch or the sugar, and (2) the action of the malt or ferment on the
paste to convert the starch into fermentable sugar.
[Illustration: Fig. 1.—MASH TUN IN AN IRISH DISTILLERY.]
_Mashing._—Figs. 1 and 2 show two views of the mashing tun or tank, the
first figure giving the general appearance, and the second a view of
the interior of the tun, showing the machinery by which the stirring is
effected and the series of pipes for cooling the finished product down
to the proper temperature for the application of the malt.
[Illustration: Fig. 2.—MASHING AND COOLING APPARATUS, CROSS SECTION.]
The object of the mash tun is to reduce the starch in the ground grain
to a pasty, gummy mass, in order that the ferment of the malt may act
upon it vigorously and convert it into sugar. If the mashing be done
before the addition {676} of the malt the temperature may be raised
to that of boiling water. If, however, the malt be added before the
mashing begins, the temperature should not rise much, if any, above
140° F., since the fermenting power is retarded and disturbed at higher
temperatures. The mashing is simply a mechanical process by means of
which the starch is reduced to a form of paste and the temperature
maintained at that point which is best suited to the conversion of the
starch into sugar.
[Illustration: Fig. 3.—FERMENTATION TANKS IN AN IRISH DISTILLERY.]
_Fermentation._—The mash, after the starch has all been converted
into sugar, goes into fermenting tanks, which in Scotland are called
“wash backs,” when the yeast is added. A view of the typical wash
back is shown in Fig. 3. They often have a stirring apparatus, as
indicated in the figure; whereby the contents can be thoroughly mixed
with the yeast and kept in motion. This is not necessary after the
fermentation is once well established, but it is advisable, especially
in the early stages, to keep the yeast well distributed throughout the
mass. In these tanks the fermentations are conducted, the temperature
being varied according to the nature of the product to be made. For
industrial alcohol the sole purpose should be to secure the largest
possible percentage of alcohol without reference to its palatable
properties.