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Woman's Institute Library of Cookery Volume 5: Fruit and Fruit Desserts; Canning and Drying; Jelly Making, Preserving and Pickling; Confections; Beverages; the Planning of Meals online

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Online LibraryWoman's Institute of Domestic Arts and SciencesWoman's Institute Library of Cookery Volume 5: Fruit and Fruit Desserts; Canning and Drying; Jelly Making, Preserving and Pickling; Confections; Beverages; the Planning of Meals → online text (page 6 of 27)
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ripeness comes the spoiling stage, and if fruits, as well as vegetables,
are canned before they are completely ripe, they are, of course, farther
from the conditions that tend to spoil them. This, however, does not
mean that green fruits or vegetables should be canned.

Whenever possible, any food that is to be canned should be perfectly
fresh. The sooner it is canned after it has been gathered, the more
satisfactory will be the results. For instance, it is better to can it
12 hours after gathering than 24 hours, but to can it 2 hours after is
much better. Fruits, such as berries, that are especially perishable
should not be allowed to stand overnight if this can be prevented; and
it is absolutely necessary to can some vegetables, such as peas, beans,
and corn, within a very few hours after gathering. Unless this is done,
they will develop a bad flavor because of _flat sour_, a condition that
results from the action of certain bacteria. Imperfect fruits should
not be canned, but should be used for making jam, marmalade, or jelly.

10. WHY CANNED FOODS SPOIL. - Canned foods spoil because of the action of
micro-organisms that cause fermentation, putrefaction, and molding. The
reasons for the spoiling of food are thoroughly discussed in _Essentials
of Cookery_, Part 2, and in that discussion canning is mentioned as one
of the means of preserving food or preventing it from spoiling. However,
when canning does not prove effective, it is because undesirable
bacteria are present in the food. Either they have not been destroyed by
the canning process or they have been allowed to enter before the jar
was closed, and have then developed to such an extent as to cause the
food to spoil. Odors, flavors, and gases result from the putrefaction,
fermentation, or molding caused by these bacteria, and these make the
foods offensive or harmful, or perhaps both.

11. PREVENTING CANNED FOODS FROM SPOILING. - From what has just been
said, it will be seen that the success of canning depends entirely on
destroying harmful micro-organisms that are present in the food and
preventing those present in the air from entering the jars in which the
food is placed.

Some foods are more difficult to keep than others, because bacteria act
on them more readily and the foods themselves contain nothing that
prevents their growth. Among such foods are meat, fish, peas, corn,
beans, and meat soups. On the other hand, some foods contain acids that
prevent the growth of bacteria, and these keep easily. Among these are
rhubarb, cranberries, and green gooseberries. However, foods that keep
easily are few, and in most cases extreme care in the process of canning
must be exercised.

12. While warmth is necessary for bacterial growth, very high
temperatures will destroy or retard it. In canning, a temperature as
high as 212 degrees Fahrenheit, or boiling point, retards the growth of
active bacteria, but retarding their growth is not sufficient. They must
be rendered inactive. To do this requires either a higher temperature
than boiling point or long continued cooking at 212 degrees. _Spores_
are a protective form that many kinds of bacteria assume under
unfavorable conditions. They are very difficult to kill, and unless they
are completely destroyed in the canning process, they will develop into
active bacteria when conditions again become favorable. The result of
the spore development is the spoiling of the food.

13. Other things besides the application of heat assist in the keeping
of canned food, as, for example, the acids of the fruits and vegetables
themselves, as has been mentioned. The use of sugar also assists; the
greater the quantity of sugar in solution the easier it will be to keep
the food. This is proved in the case of jams and jellies, which will
keep without being sealed tight or put into jars immediately after
cooking. Salt helps to keep vegetables that are canned, and, in making
butters, conserves, and pickles, the spices and vinegars used help to
protect the foods from bacterial action. However, none of these things
are essential to the keeping of any _sterile food_, by which is meant
food in which all bacteria or sources of bacteria have been rendered
inactive by the application of sufficient heat.

14. CANNING PRESERVATIVES. - Numerous compounds, usually in the form of
powders, are advertised as being useful for keeping canned foods from
spoiling. None of them should be used, however, because they are
unnecessary. If the work of canning is carefully and effectively done,
good foods will keep perfectly without the addition of a preservative.
The pure-food laws of the United States and of many of the states
themselves forbid the use of some preservatives because of their harmful
effect on the human system. For this reason, to say nothing of the extra
expense that would be incurred in their use, such preservatives may well
be left alone.


GENERAL EQUIPMENT FOR CANNING

15. The equipment required for canning depends on two things: the
quantity of food to be canned at one time and, since there are several
canning methods in use, the canning method that is to be employed.

Various kinds of elaborate equipment have been devised to make the work
of canning easy as well as effective. However, it is possible to do
excellent work with simple equipment, and if the matter of expense must
be considered there should be no hesitation about choosing the simplest
and least expensive and doing the work in the best possible way with it.
It is important also that utensils already included in the household
equipment be improvised to meet the needs of the canning season as far
as possible.

16. Whatever the canning method that is to be followed may be, there are
a number of utensils and containers that go to make up the general
equipment that is required. Familiarity with such an equipment is
extremely necessary for correct results in canning, and for this reason
the general equipment is discussed here in detail. The special equipment
needed for each of the canning methods, however, is not taken up until
the method is considered. In giving this general equipment, mention is
made of some utensils that are convenient but not absolutely necessary.
Any unnecessary, but convenient, part of a canning equipment should
therefore be chosen with a view to its labor-saving qualities and its
expense. A device that will make the keeping of canned foods more
certain and prevent loss may be a valuable purchase; still, that which
makes for greater convenience, but not absolute saving, need not be
considered a necessity.

17. VESSELS FOR CANNING. - The pots, kettles, and pans in ordinary use in
the kitchen for cooking purposes are usually satisfactory for the
canning of foods. Those made of tin or iron, however, are not so good as
enameled ones or those made of other metals, such as aluminum.
Especially is this true of utensils used for the canning of acid fruits
or vegetables, because, if such food remains in contact with tin or iron
for more than a few minutes, the acid will corrode the surface
sufficiently to give the food a bad or metallic taste. In addition, such
utensils often give the food a dark color. If enameled kettles are used
for the cooking of foods that are to be canned, it is important that the
surface be perfectly smooth and unbroken. Otherwise, it will be
difficult to prevent burning; besides, chips of the enamel are liable to
get into the food. Kettles for the cooking of fruits with sirup should
be flat and have a broad surface. Fruit is not so likely to crush in
such kettles as in kettles that are deep and have a small surface.

18. KNIVES, SPOONS AND OTHER SMALL UTENSILS. - Many of the small utensils
in a kitchen equipment are practically indispensable for canning
purposes. Thus, for paring fruits and vegetables and cutting out cores,
blossoms, and stem ends or any defective spots, nothing is more
satisfactory than a sharp paring knife with a good point. For paring
acid fruits, though, a plated knife is not so likely to cause
discoloring as a common steel knife. There are, however, other useful
implements for special work, such as the _strawberry huller_, Fig. 1,
for removing the stems of strawberries, and the _peach pitter_, Fig. 2,
for removing the stones from clingstone peaches. For placing the food to
be canned into jars, both forks and large spoons are necessities. A
large spoon with holes or slits in the bowl is convenient for picking
fruits and vegetables out of a kettle when no liquid is desired, as well
as for skimming a kettle of fruit. For packing foods into jars, a
long-handled spoon with a small bowl is convenient. Still another useful
small utensil is a short, wide funnel that may be inserted into the
mouth of a jar and thus permit the food to be dipped or poured into it
without being spilled.

[Illustration: FIG. 1]

19. DEVICES FOR MEASURING. - Accurate measures are necessary in canning;
in fact, some of the work cannot be done satisfactorily without them. A
half-pint measuring cup and a quart measure with the cups marked on it
are very satisfactory for making all measures.

Scales are often convenient, too. For measuring dry materials, they are
always more accurate than measures. Many canning proportions and recipes
call for the measurement of the ingredients by weight rather than by
measure. When this is the case and a pair of scales is not convenient,
it is almost impossible to be certain that the proportions are correct.
For instance, if a recipe calls for a pound of sugar and an equal amount
of fruit, a measuring cup will in no way indicate the correct quantity.

20. COLANDER AND WIRE STRAINER. - For the cleansing of fruits and
vegetables that are to be canned, a colander is of great assistance;
also, if a large wire strainer is purchased, it may be used as a sieve
and for scalding and blanching, steps in canning that are
explained later.

[Illustration: FIG. 2]

21. GLASS JARS. - For household canning, the most acceptable containers
for food are glass jars that may be closed air-tight with jar rubbers
and tops. Use is sometimes made of bottles, jars, and cans of various
kinds that happen to be at hand, but never should they be employed
unless they can be fitted with covers and made positively air-tight.
Like utensils, the glass jars that are a part of the household supply
should be used from year to year, if possible, but not at the loss of
material. Such loss, however, will depend on the proper sealing of the
jars, provided everything up to that point has been correctly done. All
jars should be carefully inspected before they are used, because
imperfect or broken edges are often responsible for the spoiling
of food.

In purchasing glass jars, only what are known as _first quality_ should
be selected. Cheap jars are likely to be seconds and will not prove so
satisfactory. Glass jars may be purchased in sizes that hold from 1/2
pint to 2 quarts. If possible, food should be canned in the size of jar
that best suits the number of persons to be served.

If the family consists of two, pint jars will hold even more than may be
used at one time, while if the family is large the contents of a quart
jar may not be sufficient.

[Illustration: FIG. 3]

22. Numerous types of glass jars are to be had. Some of them are more
convenient than others and may be made air-tight more easily. These two
features are the most important to consider in making a selection. Jars
that close with difficulty, especially if the tops screw on, are not
likely to keep food successfully because the bacteria in the air will
have a chance to enter and thus cause the food to spoil.

Glass jars used for canning foods have improved with canning methods.
The old-style jars had a groove into which the cover fit, and melted
sealing wax or rosin was poured into the space surrounding the cover.
Later came the screw-top jar shown in Fig. 3. This type of jar has been
extensively used with excellent results. Both the mouth of this jar and
the jar top, which is made of metal, usually zinc, lined with glass or
porcelain, have threads that match, and the jar is sealed by placing the
jar rubber over the top, or ridge, of the jar and then screwing the jar
top firmly in place. Such jars, however, are more difficult to make
air-tight than some of the newer types. One of these jars is illustrated
in Fig. 4. It is provided with a glass cover that fits on the ridge of
the jar and a metal clasp that serves to hold the cover in place and to
make the jar air-tight after a rubber is placed in position. Another
convenient and simple type of glass jar, known as the _automatic seal
top_, has a metal cover with a rubber attached.

Another improvement in jars is that the opening has been enlarged so
that large fruits and vegetables, such as peaches, tomatoes, etc., can
be packed into them whole. With such wide-mouthed jars, it is easier to
pack the contents in an orderly manner and thus improve the appearance
of the product. Besides, it is a simpler matter to clean such a jar than
one that has a small opening.

[Illustration: FIG. 4]

23. JAR TOPS AND COVERS. - While the tops, or covers, for glass jars are
made of both metal and glass, as has been stated, the glass tops meet
with most favor. Of course, they are breakable, but they are even more
durable than metal tops, which are usually rendered less effective by
the bending they undergo when they are removed from the jar. Covers made
of zinc are being rapidly abandoned, and it has been proved that the
fewer the grooves and the simpler the cover, the more carefully and
successfully can it be cleaned. For safety, glass tops that have become
chipped or nicked on the edges that fit the jar should be replaced by
perfect ones. The covers for automatic-seal jars must be pierced before
they can be removed, and this necessitates a new supply for each
canning. If there is any question about the first-class condition of jar
covers, whether of metal or glass, tops that are perfect should
be provided.

24. JAR RUBBERS. - Jar rubbers are required with jar tops to seal jars
air-tight. Before they are used, they should be tested in the manner
shown in Fig. 5. Good jar rubbers will return to their original shape
after being stretched. Such rubbers should be rather soft and elastic,
and they should fit the jars perfectly and lie down flat when adjusted.
A new supply of rubbers should be purchased each canning season, because
rubber deteriorates as it grows old. Rubbers of good quality will stand
boiling for 5 hours without being affected, but when they have become
stiff and hard from age it is sometimes impossible to make jars
air-tight. Occasionally, two old rubbers that are comparatively soft may
be used in place of a new one, and sometimes old rubbers are dipped in
paraffin and then used. However, if there is any difficulty in sealing
jars properly with rubbers so treated, they should be discarded and good
ones used.

25. TIN CANS. - For household canning, tin cans are not so convenient as
glass jars, but in spite of this they are coming into extensive use. The
kind that may be used without any special equipment has a tin lid that
fits into a groove and is fastened in place with rosin or sealing wax.
Some cans, however, require that the lids be soldered in place. While
soldering requires special equipment, this method of making the cans
air-tight is the best, and it is employed where considerable canning is
done, as by canning clubs or commercial canners.

[Illustration: FIG. 5]

In the purchase of tin cans, the size of the opening should receive
consideration. If large fruits and vegetables, such as peaches, pears,
and tomatoes, are to be canned, the opening must be a large one;
whereas, if peas, beans, corn, and other small vegetables or fruits are
to be canned, cans having a smaller opening may be chosen. When acid
fruits or vegetables are to be canned, use should be made of cans that
are coated with shellac, as this covering on the inside of the cans
prevents any action of the acid on the tin.

* * * * *

CANNING METHODS

GENERAL DISCUSSION

26. The methods employed for the canning of foods include the
_open-kettle method_, the _cold-pack method_, the _steam-pressure
method_, and the _oven method_. Of these, the open-kettle method is
perhaps the oldest household method of canning, and it is still used by
many housewives. The other methods, which are newer, seem troublesome to
the housewife who is familiar with the open-kettle method, yet it will
only be fair to give the new methods a trial before deciding which to
use. The one-period cold-pack method has much to recommend it. Foods
canned in this way undergo less change in form and flavor than those
canned by the open-kettle method; besides, there is less danger of
spoiling. In fact, many foods, such as vegetables and meats, that cannot
be canned satisfactorily by the open-kettle method will keep perfectly
if they are carefully preserved by the one-period cold-pack method. The
steam-pressure method requires the use of special equipment, as is
explained later. While it is a very acceptable canning method, it is not
accessible in many homes. The oven method is liked by many housewives,
but it offers almost the same chance for contamination as does the
open-kettle method.


OPEN-KETTLE METHOD

27. The OPEN-KETTLE METHOD of canning is very simple and requires no
equipment other than that to be found in every kitchen. It consists in
thoroughly cooking the food that is to be canned, transferring it to
containers, and sealing them immediately.

28. UTENSILS REQUIRED. - Not many utensils are required for the
open-kettle canning method. For cooking the food, a large enamel or
metal vessel other than tin or iron should be provided. It should be
broad and shallow, rather than deep, especially for fruit, as this food
retains its shape better if it is cooked in a layer that is not deep.
The other utensils for canning fruits and vegetables by this method are
practically the same as those already discussed - measuring utensils, a
knife, large spoons, pans for sterilizing jars or cans, covers, rubbers,
and jars or cans into which to put the food.

29. PROCEDURE. - The first step in the open-kettle canning method
consists in sterilizing the containers. To do this, first clean the
jars, covers, and rubbers by washing them and then boiling them in clear
water for 15 to 20 minutes.

Next, attention should be given to the food that is to be canned. Look
it over carefully, cut out any decayed portions, and wash it thoroughly.
Sometimes roots, leaves, stems, or seeds are removed before washing, and
sometimes this is not done until after washing. At any rate, all dirt or
foreign material must be washed from foods before they are ready
for canning.

After preparing the food, it must be cooked. If fruit is being canned,
put it into the required sirup, the making of which is explained later,
and cook it until it is well softened, as if preparing it for immediate
table use. If vegetables are being canned, cook them in the same way,
but use salt and water instead of sirup. When the food is cooked,
transfer it to the sterile jars and seal at once with the sterile
rubbers and covers. Then invert each jar to permit the food to cool and
to test for leaks.

30. The danger of not securing good results with the open-kettle method
lies in the possibility of contaminating the contents before the jar is
closed and sealed. In addition to having the jars, rubbers, and covers
sterile, therefore, all spoons and other utensils used to handle the
cooked food must be sterile. Likewise, the jars must be filled to the
top and the covers put on and made as firm and tight as possible at
once, so that as few bacteria as possible will enter. If screw-top cans
are used, the tops should not be twisted or turned after cooling, as
this may affect the sealing. If jars leak upon being turned upside down,
the contents must be removed and reheated and the jar must be fitted
with another cover. Then both jar and cover must be sterilized and the
contents returned and sealed immediately.


COLD-PACK METHOD

31. The COLD-PACK METHOD of canning differs from the open-kettle method
in that the food to be canned is not cooked in a kettle before placing
it in the jars and sealing them. In this method, the food to be canned
is prepared by washing, peeling, scraping, hulling, stemming, seeding,
or cutting, depending on the kind. Then it is _scalded_ or _blanched_
and plunged into cold water quickly and taken out immediately, the
latter operation being called _cold-dipping_. After this it is placed
into hot jars, covered with boiling liquid - boiling water and salt for
vegetables, meats, fish, or soups, and boiling sirup for fruits. Then
the filled jars are covered loosely and placed in a water bath and
_processed_; that is, cooked and sterilized. When food that is being
canned is subjected to processing only once, the method is referred to
as the _one-period cold-pack method_; but when the food in the jars has
not been blanched and cold-dipped and is processed, allowed to stand 24
hours and then processed again, and this operation repeated, it is
called the _fractional-sterilization method_. The equipment required for
the cold-pack canning method and the procedure in performing the work
are taken up in detail, so that every point concerning the work may be
thoroughly understood.

[Illustration: FIG. 6]

32. UTENSILS REQUIRED. - The utensils required for canning by the
cold-pack method are shown assembled in Fig. 6. Chief among them is a
_sterilizer_, or boiler, which consists of a large fiat-bottomed vessel
fitted with a rack and a tight-fitting cover. A number of such devices
are manufactured for canning by the cold-pack method, but it is possible
to improvise one in the home. A wash boiler, a large pail, a large lard
can, or, in fact, any large vessel with a flat bottom into which is
fitted a rack of some kind to keep the jars 3/4 inch above the bottom
can be used. Several layers of wire netting cut to correct size and
fastened at each end to a 3/4-inch strip of wood will do very well for a
rack. In any event, the vessel must be deep enough to allow the water to
cover the jars completely and must have a tight-fitting cover. Besides a
sterilizer, there are needed three large vessels, one for scalding the
food that is to be canned, one for cold-dipping, and one for keeping the
jars hot. To hold the food that is to be dipped, a sieve, a wire
basket, also shown in Fig. 6, or a large square of cheesecloth must also
be provided, and for placing jars in the water bath, a can lifter, a
type of which is shown on the table in Fig. 6, may be needed. The
remainder of the equipment is practically the same as that described
under the heading General Equipment for Canning.


PROCEDURE IN THE ONE-PERIOD COLD-PACK METHOD

33. PREPARING THE CONTAINERS. - The first step in the cold-pack method
consists in preparing the containers for the food. The jars, rubbers,
and covers, however, do not have to be sterilized as in the open-kettle
method. But it is necessary first to test and cleanse the jars and then
to keep them hot, so that later, when they are filled and ready to be
placed in the water bath, they will not crack by coming in contact with
boiling water. The best way in which to keep the jars hot is to let them
stand in hot water.

[Illustration: FIG. 7]

34. PREPARATION OF THE FOOD. - Attention should next be directed to the
preparation of the food to be canned; that is, clean it and have it
ready for the processes that follow. The fruits or vegetables may be
canned whole or in pieces of any desirable size. What to do with them is
explained later, when the directions for canning the different kinds are
discussed. While the food is undergoing preparation, fill the sterilizer
with hot water and allow it to come to the boiling point.

35. SCALDING AND BLANCHING. - When the food is made ready, the next step
is to scald or blanch it. Scalding is done to loosen the skin of such
food as peaches, plums, and tomatoes, so that they may be peeled
easily. To scald such fruits or vegetables, dip them quickly into
boiling water and allow them to remain there just long enough to loosen
the skin. If they are ripe, the scalding must be done quickly; otherwise
they will become soft. They should never be allowed to remain in the
water after the skin begins to loosen. For scalding fruits and
vegetables a wire basket or a square of cheesecloth may be used in the
manner shown in Figs. 7 and 8.



Online LibraryWoman's Institute of Domestic Arts and SciencesWoman's Institute Library of Cookery Volume 5: Fruit and Fruit Desserts; Canning and Drying; Jelly Making, Preserving and Pickling; Confections; Beverages; the Planning of Meals → online text (page 6 of 27)