The Manufacture of Tomato Products
_INCLUDING_ Whole Tomato Pulp or Puree, Tomato Catsup, Chili Sauce,
Tomato Soup, Trimming Pulp
_BY_
W. G. HIER
_Technologist in the Canning and Preserving of Tomato Products_
Formerly Chief Chemist and District Factory Supervisor of The T. A.
Suider Preserve Co. of Chicago
[Illustration]
Published by
W. G. HIER
2324 South Columbine Street
Denver, Colorado
COPYRIGHT 1919
BY
W. G HIER
DENVER
THE BROCK-HAFFNER PRESS CO., PRINTERS
1919
Preface
The past ten years have seen revolutionary changes made in the tomato
product manufacturing business. Old methods of making tomato pulp,
catsup, chili sauce, etc. have been discarded, and the modern plant
presents a very striking contrast to the plant of former days.
In this book I have tried to present all the methods used which have
merit, and to bring forth the advantages and disadvantages of each so
that the packer can weigh them and decide which is best to use under the
conditions which obtain at his plant. In some cases one method is
universally applicable and has advantages which stamp it as superior,
but more often varying conditions of manufacture in different localities
make it impossible to recommend any one method for everyone.
In writing the text I have had to rely almost entirely on the experience
gained during the seven years in which I have been engaged in the
manufacture of these products, as there are no books on the subject, and
no sources of reference except the bulletins prepared by Mr. B. J.
Howard and Mr. C. H. Stephenson of the Bureau of Chemistry, U. S.
Department of Agriculture, on the sorting and washing of tomatoes, the
handling of tomato trimmings, and the effect of proper and improper
sorting and washing on the content of micro-organisms as determined by
microscopical examination.
I wish to thank Mr. B. J. Howard of the Bureau of Chemistry for the
valuable suggestions and information he gave me with reference to
portions of the text of Chapter II and Chapter VII, and also to thank
the Bureau of Chemistry for permission to use many of their
photomicrographs and photographs.
W. G. HIER.
April 22, 1919.
PART I
The Manufacture of Whole Tomato Pulp or Puree
Table of Contents
PART I
THE MANUFACTURE OF WHOLE TOMATO PULP OR PUREE
PAGE
CHAPTER I. OBTAINING GOOD TOMATO STOCK 1
Value of good tomato stock—plant raising—use of
fertilizer—methods in east and west—shipping tomatoes—tomato
crates—degrees of ripeness for shipping—careful handling at
factory—varieties—storing tomatoes—stemless tomatoes.
CHAPTER II. WASHING AND SORTING 8
Washing and sorting equipment—rotary washer—water bath with
compressed air—importance of agitation—plain sorting belt—number
of sorters—tomato turning device—divided sorting
belt—sorting—forms of decay—cleanliness of equipment—molds,
yeasts and spores, and bacteria.
CHAPTER III. PRINCIPAL METHODS IN USE FOR PULPING 20
Cold pulping—care of cyclone—hot pulping—advantages claimed for
hot pulping—objections to hot process—crushing—conveying to
kettle—value of pumice.
CHAPTER IV. CONDENSING THE STRAINED OR CRUSHED TOMATOES 26
Vacuum pan—types of open kettles—steam pressure—copper jacketed
kettles—tinning kettles—advantages of various types of
kettles—glass-lined tank—cypress tank—cleaning kettles—coil
leaks—starting the cooking—methods of gauging finishing
point—cooking to gauge on kettle—cooking a definite length of
time—determining specific gravity by weight—objections to
weighing method—testing with hydrometer—method of using
hydrometer—finishing the cook.
CHAPTER V. CONVEYING THE CONDENSED, STRAINED, OR CRUSHED TOMATOES
TO THE FINISHING MACHINE, AND FINISHING SAME 38
Conveying to finisher—receiving tanks—finishing—screen metal for
finisher—effect of finishing on mold count—finishing before
cooking.
CHAPTER VI. FILLING THE FINISHED PULP AND STORING THE CANNED
PRODUCT 41
Filling devices for five gallons—square can and round
can—testing for leaks—washing and steaming—filling and
capping—handling filled cans—advantages of separating
batches—how to stack—processing—life of cans—washing and drying
cans—protection from dust—testing used cans—packing No. 10’s and
No. 1’s—packing barrel pulp—metal drums—a method of preserving
pulp in barrels.
CHAPTER VII. THE MICRO-ORGANISMS OF TOMATO PRODUCTS; THE ATTITUDE
OF THE PURE FOOD AUTHORITIES TOWARD THEM; AND THE INTERPRETATION
OF ANALYSES 51
Micro-organisms; what they are—molds—bacteria—yeasts—spores—how
germs retard their own growth—rapidity of growth—the government
attitude on micro-organisms—government regulations—state food
officials—checking up daily runs—how to interpret analyses.
PART II
THE MANUFACTURE OF TOMATO CATSUP, CHILI SAUCE, TRIMMING PULP, AND
TOMATO SOUP
CHAPTER VIII. A DISCUSSION OF PRESERVATIVE AND NON-PRESERVATIVE
CATSUPS; AND THE MOST FREQUENT CAUSE OF INFERIORITY 73
Unfavorable publicity on preservatives—“natural”
preservatives—proper acidity—processing catsups—advantage of
benzoate catsups—causes of poor color and flavor—advantage of
direct conversion of tomatoes into catsup—thickness—spicing and
sweetness—“black neck”—general attractiveness.
CHAPTER IX. A DISCUSSION OF THE INGREDIENTS OF CATSUP; WHEN AND
HOW THEY SHOULD BE ADDED; AND THE AMOUNTS OF EACH PER 100
GALLONS OF FINISHED CATSUP 80
Measuring the volume of tomato juice—amount of tomatoes—keeping
batches uniform—use of spices in a sack—use of spices direct and
when to add them—use of spices in two batches—what is
extracted—storing spices—quality of flavor—use of essential
oils—how to add essential oils—paprika—quantities of spices and
oils per batch—essential oils economical—adulteration of ground
spices—onions and garlic—sugars—sugar syrups—use of sugar in
large quantities—salt—vinegar—transference of vinegar—adding the
vinegar—acidity—testing finishing point—holding batches—making
catsup from pulp—use of benzoate of soda.
CHAPTER X. FINISHING, BOTTLING, STERILIZING, AND STORING THE
CATSUP 97
The receiving tank and finisher—filling and sealing—washing the
filled bottles—processing—advantages of omitting
processing—process method—time and temperature—temperature
controlling and recording devices—non-process method—which
method is the better?—labeling and casing—stacking catsup to
avoid “black neck”—packing gallons and No. 10’s.
CHAPTER XI. THE MANUFACTURE OF CHILI SAUCE AND THE PULPING OF
TOMATO TRIMMINGS 107
Grading the tomatoes—method of handling tomatoes—amount of
tomatoes and onions—spices—salt, sugar and vinegar—testing
finishing point—filling, sealing and sterilizing—microscopical
counts—pulping the trimmings—government attitude on trimming
pulp—method of handling tomatoes when trimmings are pulped.
CHAPTER XII. THE MANUFACTURE OF TOMATO SOUP 112
Convenience and economy of canned soup—factors upon which
success depends—unpalatability—proper sweetness—gradual souring
of pulp—sampling—proper acidity—price and quality—microscopical
counts—beginning the cook and adding soda—butter, onions, and
spices—sugar and salt—testing thickness before adding
flour—adding flour—filling and processing—shaking and labeling.
CHAPTER I
OBTAINING GOOD TOMATO STOCK
Value of Good Tomato Stock
Obtaining a good quality of tomatoes at a price which is not prohibitive
is a problem which in many localities is becoming more difficult to
canners and catsup makers each year. Every experienced manufacturer
knows that regardless of the expertness with which he may work up his
tomatoes into the finished product, he cannot expect to get good quality
unless he has good stock to begin with. It is true that by using
intelligence and extreme care in the manufacturing processes one
manufacturer will make better pulp or catsup from tomatoes of fair
quality than another man can get from the best quality of stock. This
same care and intelligence applied, however, in working up high quality
tomatoes will probably show a greater difference in the finished
products than was apparent in the tomatoes from which these products
were made; in other words, the goodness of good tomatoes becomes
accentuated by the manufacturing process.
In order to insure as large a proportion as possible of good quality
stock, as well as a good yield per acre in tonnage, manufacturers are
each year realizing the necessity of closer co-operation with the
farmer. Where in growing tomatoes under contract it was formerly largely
up to the farmer to buy his seed and raise his plants and set them out,
it is now the usual custom to supply the farmer with seed of the desired
variety and of high germination test, and in many cases to go a step
farther and supply him with plants six to eight inches high, ready for
setting out in the field. Unquestionably, the best results are secured
by growing the plants for the farmer. The average farmer does not go
about the raising of his plants in an intelligent way, and he will not
devote the time to the plant-raising business that it should have.
Plant Raising
Most packers are agreed that the best plant is raised by starting the
seeds in rows in hot beds, transplanting to cold frames when they are
two to four inches high to harden them and make them stocky, and again
transplanting to the field when the plants are six to eight inches high.
This method produces a dark green, bushy, thick-stemmed plant of high
vitality, which is so essential to a good yield. What a contrast to the
average plant raised by the farmer—the seed often broadcasted, either in
a hot bed or in a spot in the garden where the soil has not been
specially prepared for plant raising, and when the plants, a large
number of which are thin, pale green, and spindly looking, attain a
height of anywhere from six inches to a foot they are all set out in the
field and allowed to struggle along as best they can. When one looks at
the kind of plants that are so often set out he can see at least one
reason why yields of from three to seven tons per acre are so often
obtained from ground which should yield twice that much, and why the
plants are easy victims to blight and other diseases.
A prominent canner recently told me that by raising the plants for his
farmers he had increased the average yield 4 tons per acre.
Use of Fertilizer
So many articles have been written on tomato culture for canning plants
by experienced horticulturists that the subject will not be dealt with
extensively here. In these articles emphasis is usually laid on the
desirability of the use of commercial fertilizer, not only to increase
the yield, but to hasten the maturing of the crop so that a large
proportion of it can be harvested before frost.
My experience testifies to the wisdom of this in practically all cases,
and with late maturing varieties such as the Stone tomato, in regions
subject to early frost, and especially where planted on low ground, it
is absolutely essential that fertilizer be used if a good percentage of
the crop is to be harvested.
Methods in East and West
In the Tri-States—that is, Delaware, Maryland, and New Jersey—quite a
different situation exists from that in the middle west or far west. The
western packer has practically all of his tomatoes grown under contract,
while the Tri-State packer, although he tries to contract as much
acreage or tonnage as possible at a reasonable figure, is up against the
competitive buying of the open market for a large proportion of his raw
stock, as there are always a large number of farmers who are willing to
gamble that the coming season will be a good one for playing the open
market. In this case the buyer usually cannot be as particular about the
quality of the tomatoes he buys as can the packer who has his tomatoes
all grown under contract at a specified price, and who can exercise
supervision over his farmers. This is particularly true in seasons of
short crop, when the grower sells his tomatoes on the market and can
afford to be very independent, and buyers are wildly forcing up the
price by competitive bidding, and taking whatever they can get. Even if
the eastern grower is under contract for his entire crop, if the crop is
short, and high prices are prevailing on the market, it is the
exceptional grower who will live up to his contract, and often to get an
excuse for breaking his contract he will deliver very poor tomatoes
right along in the hope that they will be objected to, thus giving him
the liberty of disposing of them elsewhere.
The eastern packer, however, is blessed with a longer season in which to
operate. While in the west there are seldom enough tomatoes to justify a
run at the factory before August 15th, the Tri-States packer starts in
on the early crop about the 25th of July, and his crop is not as liable
to be severely injured by an early frost as is the western crop.
Canning and preserving plants in the west, being scattered rather
sparsely over a very large territory, and being farther away from the
large centers of population than in the east, the western packer is able
to get a large percentage of his tomatoes hauled to the factory by
wagon. This is indeed a big advantage, not only in the saving of freight
and handling expense, but in the condition of the fruit when delivered
to the factory. Probably having been picked not more than twenty-four
hours before delivery, the wagon-hauled tomatoes are solid, and because
the skin is not broken by repeated handling, thus preventing the growth
of molds, they require very little sorting, in fact, no sorting at all
in some cases. A load of tomatoes which requires no sorting at all,
however, is unusual. If the packer can get his growers to use spring
wagons for hauling tomatoes, it is a big advantage, especially if the
fruit must be held any length of time at the factory. If the
wagon-hauled tomatoes can be worked up quickly the packer gets 100 per
cent value for them, which he very seldom does get on shipped tomatoes,
which commonly undergo a loss of between 5 and 20 per cent in shipment,
depending upon the time involved in shipment, the ripeness of the fruit,
the amount of handling it received, the condition of the weather, the
kind of crate in which the fruit is packed, and the amount of
ventilation it received in transit.
Shipping Tomatoes
Shipment by water, although slow, has the advantage of smoothness of
transit, and the crates or baskets of tomatoes are not subjected to the
frequent joltings of rail shipments, and it is to be remembered that
every jolt makes the tomatoes settle to a certain extent in the crates
and mashes the tomatoes in the bottom layers. The best car for rail
shipments is the slatted car or stock car, which permits of better
circulation than any of the other types. A box car should never be used,
as it allows the fruit to heat very badly, and there is no circulation
of air. The crates in the slatted cars should be so stacked as to allow
as much circulation of air through the car as possible. However, care
must be taken that the crates are so stacked that they will not shift. A
small air space can always be left at the end of every other row on each
side without endangering the stability of the crates, and a large air
space can be left at the top.
Tomato Crates
One advantage in the use of the basket over the crate in shipments is
the advantage of better circulation of air through the piled baskets of
fruit, due to the conical shape of the basket. Good ventilation is thus
supplied without danger of the baskets shifting during shipment. The
⅝-bushel basket is used almost universally in the east, while in the
west the crate holding a bushel is the common container. The
construction of the crate is a more important item than is often
thought. The most important point, of course, is strength in
construction, and the use of a wood which will not warp easily by
alternate soaking and drying out, allowing the nails to become loose and
the bottoms to begin to fall out of the crates after a half season’s
use. The slats of the crates should have rounded, smooth edges so as not
to cut the surface of the tomatoes when they are jolted and weighted
down during shipment. The slats should be only close enough together to
hold the small tomatoes, so as to permit of as much air circulation as
possible. This particularly applies to the bottom of the crates, which
become soggy and musty after a little use, and the openings soon become
clogged up with tomato substance. It is important to turn a steam hose
over the bottoms of such crates to clean them out before returning to
the point of shipment. If the empty crates pass along on a chain belt
after dumping, this steaming can be accomplished easily. Accumulated
decaying tomato substance in the bottom slats not only rots out the
crates, but contaminates otherwise good tomatoes every time the crate is
used. The crate should also be as shallow as will permit of easy
handling, so as to distribute the weight of the tomatoes over as much
surface as possible. A shallow, broad crate is preferable to a deep,
narrow one.
Degrees of Ripeness for Shipping
The proper degree of ripeness for tomatoes to be shipped depends, of
course, upon the length of time it will take for them to arrive at their
destination. Dead-ripe tomatoes will stand very little handling and
shipping, particularly if the weather is warm and damp, as it so
frequently is during tomato season. It is important, too, not to have
the tomatoes delivered to the shipping station too underripe, as they
are very apt to rot before they become red enough to cook up into a
product of good color. That the employee in charge of receiving tomatoes
at the shipping point should be a man of experience and good judgment as
well as tact in dealing with the farmers, is apparent. So much depends
upon the control he exercises over the farmers in getting them to pick
their fruit at the proper degree of ripeness. If he falters, is
uncertain, and changes his mind a few times, he is lost, as the farmers
soon lose confidence in his judgment.
It is always difficult to impress upon the farmer the fact that tomatoes
gain in weight during the ripening process, and the riper they have
their tomatoes the more they get in dollars when they drive up on the
scales. This argument cannot be advanced when the tomatoes are bought by
the basket, as they are in the east, but when paid for according to
weight and not volume, the ripeness of his tomatoes is an important
point for the farmer to watch. At the tail end of the season when frosts
are threatening, this argument of the increased weight of tomatoes which
are red ripe all over of course loses its effect entirely. All the
farmer is interested in at that time is in getting as many of his
tomatoes as possible accepted before a heavy frost finishes them. At
this time increased vigilance at the receiving end is necessary.
Careful Handling at Factory
The less handling crates or baskets of tomatoes receive, the better.
Every packer wants to eliminate handling as much as possible to conserve
labor, but when one sees the laborers around the average plant heaving
crates of tomatoes around as though they were pig iron, he wonders if
the manager fully realizes the effect of this bouncing of heavy crates
of tomatoes on to trucks, receiving platforms, etc. It is just as easy,
or almost as easy, to set the crates down gently, but the laborers who
do this work must be constantly reminded of it. You do get tired of
constantly hammering at them, but it is surely worth the effort. A
common attitude for the men to take is that the tomatoes are all going
to get mashed up anyway pretty soon, so what’s the difference. When you
consider the fact that crates of tomatoes are commonly handled from six
to eight times before they reach the sorting belt, this handling often
consisting of dropping the crates down so hard that the top tomatoes
almost bounce out, it is no wonder that when they are spread out on the
sorting belt the bottom layer of each crate is mashed and moldy, so that
half of these bottom tomatoes have to be thrown away.
Varieties
Any of the brilliant red varieties of tomatoes are suitable for catsup
or pulp making. Those varieties having a purplish cast should be
avoided, as they cook up into a product having a brownish color. The
smooth, round varieties, such as the Stone, are especially good for
peeling, while the flat varieties, and those having a very coarse,
uneven surface, are well suited for pulp or catsup.
Storing Tomatoes
For storing the tomatoes at the factory until they can be put over the
sorting belts the open-air storage is used almost universally, and it
seems to be the only method which can be economically employed at a
plant which handles large quantities of tomatoes. I have seen the wet
storage method in use at a small plant where the receipts only amount to
a few hundred bushels a day on good days, and less than a hundred on
many days when the weather is very bad, and it was liked very much by
the plant manager. The tomatoes, as soon as received, were dumped into a
large concrete tank of cold water, which was kept fairly fresh by
letting fresh water run into it constantly, with an overflow at the
other side of the tank, and a large revolving paddle at one side of the
tank kept the water in motion. Attached to this paddle was a series of
flights on an endless chain, which, when thrown into gear, carried the
tomatoes to the sorting belt.
The argument advanced in favor of the wet storage method by the operator
of this plant was that at certain times in the season their receipts of
tomatoes were very small, that is, at the beginning and at the close of
the season, and during stretches of cold, rainy weather, and at such
times they only made a run every other day, or possibly only twice a
week, and that the tomatoes kept much better in wet storage.
The tomatoes were clean when delivered to the sorting belt, and although
they received very little sorting, and only one spraying after they left
the storage tank, the count of molds, yeasts and spores and bacteria on
their pulp was fairly low.
The wet storage method could undoubtedly be used at large plants, and
might prove profitable during periods of glut, as there is no doubt but
what tomatoes will keep better in wet storage than in the open air. It
would take a lot of tanks for a large plant, however, and large
operators are not inclined to look favorably on the idea.
In open-air storage the crates of tomatoes should be stacked so as to
leave an air space between each crate, and if stacked inside of a
building, all the windows and doors should be thrown open to allow as
free a circulation of air as possible.
Stemless Tomatoes
Most tomatoes are delivered to the factory with the stems on, but I know
of one plant where they are all received stemless, and the quality of
the pulp made from them simply cannot be beat. There surely must be an
undesirable taste imparted by all these green stems in the cooking
process. Of course, where the cold pulping process is used, that is, the
tomatoes pulped cold directly after sorting and washing, these stems are
eliminated before any cooking is done. In the hot pulping process,
however, and when the tomatoes are put in a crusher instead of a pulp
machine, the stems are cooked along with the rest of the pulp. The
operator of the plant referred to above pays a bonus of a dollar a ton
to his contractors for having the tomatoes delivered stemless, and he
believes he gets that dollar back and more, too, in the price he gets
for his product, which is very fancy.