Principles Of Canning And Preserving

ALL kinds of fruit and most vegetables can be preserved in cans or in glass jars by methods easily applied in the home. During the past few years, much experimental work has been carried on by worthy organizations and clubs, in an effort to perfect an all-round, satisfactory home-canning method,— one that is simple to understand, easy to follow, and does not require expensive equipment to make it successful. So far there are three methods being used, and the good points as well as the weak points in each become manifest as we study them.

1. The hot-pack or open-kettle method, cooking in a kettle the foods to be canned, either in their own juice or in a sirup, then sealing them in sterilized jars. This method is successful for acid fruits and acid vegetables, but will not do for non acid products, such as corn, peas, beans, etc. It is also difficult to retain the shape and color of the products canned in this way.

2. The three day intermittent method has also been used in canning vegetables. It consists in packing the uncooked products in sterilized jars, filling the jars with water or sirup, putting the lids in place, placing the jars on a rack in a boiler, filling the boiler with water to cover the tops of the jars, and letting the water boil around the jars for I hour. The jars are then set aside, for 24 hours. The next day, they are placed back in the vessel, and cooked in boiling water for 1 hour again. They are then set aside for 24 hours more, and the cooking is repeated the third day, which completes the process. The first boiling destroys the bacteria, but not the spores, or seeds. As soon as the jars cool, these spores germinate ; and the boiling on the second day kills this crop of bacteria before they have had time to develop spores. Boiling on the third day is not always necessary, but is a prevention against possible growths.

While the theory back of this method is absolutely correct, so far as the keeping qualities of the food are concerned, the three days’ cooking is too much cooking for many foods, as it destroys both the color and the flavor. Moreover, it is a long and tedious work; and in the use of glass jars, the prolonged cooking weakens the seal. While the above method is a sure one, especially when sealed tins are used, the same results may be obtained by a much quicker method, and with keeping qualities fully as good.

3. The cold-pack method seems to have overcome all the objections in the foregoing methods, besides presenting new and tried theories. This method simply consists in packing uncooked foods in jars, then cooking them in the closed jars for a given length of time, figured out as best suited to each food. All foods do not need to be and should not be cooked the same length of time, and herein is where the cold-pack method is most successful. Foods are sterilized, and their flavor and color best retained, when definite time-tables are followed, which have been developed after much experimenting. In carrying out the cold-pack method, the procedure is made easy by observance of the following six steps :

1. Preparation. The materials are cleaned, pitted, peeled, or sliced, to make them more attractive, and to avoid preserving useless material.

2. Blanching. This means to parboil, or scald a given length of time, which varies from 1 to 15 minutes, depending on the kind of product. For berries and soft fruits, the blanching is omitted. After washing the fruit or vegetables in cold water, as if to cook and serve, put into a cloth bag, and drop into boiling water for the required length of time, counting the time after boiling begins.

3. Cold Dip.— Lift the bag of vegetables or fruit from the boiling water, and immediately plunge into cold water, lift, and drain. This cold dip sets the color and shrinks the food after it has been in the boiling water.

4. Packing.— The product is then immediately packed in hot jars. In the case of fruits, hot sirup or hot water is added. In the case of vegetables (except tomatoes), hot water is added, with salt in the proportion of 1 level teaspoon to each quart jar of food. The sterilized rubbers and tops are then put in place. If using the “composition sealing lid,” secure with screw band, or clamp. If using screw top jars with rubber ring, seal only partially, using the thumb and the little finger only. This makes it possible for the steam gendered within the jar to escape, and prevents breakage.

5. Hot-Water Bath.— In a vessel containing boiling water in which the jars have been sterilized, a false bottom is placed. Upon this the jars are set to keep them from resting flat on the bottom of the boiler, and thus the water is allowed to circulate under them. Wooden laths, wire, or wire netting will answer the purpose.

6. Processing.— Place the jars on the rack in the boiler. Fill with warm water to cover the tops of the jars by at least i inch. This will prevent any liquid from being lost during the cooking, as it is likely to be if the water does not cover the tops of the jars, or if the covers are adjusted too loosely. The time is counted from the moment the water boils up well. As soon as the time is up, the water is lowered by dipping out a portion, the jars are removed, and the covers are tightened. When using jars with sealing composition tops, secure the lids with screw bands or clamps before putting them into the water; and when the processing is completed, set the jars aside, and the cooling of the jars seals them. Jars with rubber rings and screw tops, being only partially sealed while in the water bath, are sealed tightly when removed from the boiling water, and inverted to test the seal.

An example is given in the following recipe for string beans. Other vegetables may be canned in like manner (if the taste of acid is not objectionable), except corn, which requires half again as much lemon juice as do string beans.


Prepare the string beans as in the preceding recipe. Add boiling water in a saucepan barely to cover the beans, with salt to taste. Cover (except the cover must be drawn to one side far enough to allow the steam to escape), and let boil continuously for 30 or 35 minutes. Lift a glass jar out of boiling water, and put on a hot scalded rubber ring. Into each quart jar put 2 tablespoons lemon juice, and fill the jar with boiling beans. Add enough of the boiling liquid to overflow the jar; then screw the cap on tightly, invert, and let cool.


Remove the husk and the silk, blanch, dip, drain, and cut from the cob. Pack immediately into jars or tin cans, to within 1/2 inch of the top. Add a teaspoon of salt to the quart, and fill with boiling water. Put on the rubber rings, and screw the caps on with the thumb and the little finger. (Seal tin cans completely.) Cook for the length of time given in the table, for the particular kind Of cooker used.


Break open, and remove the seeds and the stringy fiber. Peel, cut into small pieces, and boil until thick. Pack into jars, and sterilize for the length of time given for the particular kind of cooker used.


Blanch, dip, drain, and remove the skins and the hard part near the stem end. Cut into halves or quarters, and pack into jars or tin cans, with a teaspoon of salt to each quart. Put on rubber rings, and adjust the caps the same as for corn. (Seal tin cans completely.) Cook for the length of time given for the particular kind of cooker used.


Prepare the tomatoes the same as in the preceding recipe, and place in an open kettle. Bring gradually to the boiling point, and let simmer until thoroughly cooked through. Have the jars and the caps sterilized. Lift them one at a time out of boiling water, adjust the rubber, and fill with boiling tomato. Put on the cap, and screw down tightly, being careful not to touch the inner part of jar, rubber, or jar cap with the fingers in handling. Invert and let cool.


Vegetables can be preserved more cheaply than in cans or jars, and more simply for household use than by drying. The method makes use of the preservative qualities of salt. The following formula is given out by the Division of Viticulture, College of Agriculture, Berkeley, California:

“The vegetables are first washed and sliced. Weigh them, and take I pound of salt for each 2 pounds of prepared vegetables. A layer of salt is first placed on the bottom of the crock or barrel, and then a layer of vegetables. Similar layers are alternated until the vessel is full, finishing with a layer of salt. A wooden cover is then applied, and weighted with a stone or similar object that will not be acted upon by the brine. After a few days, there will be a considerable shrinkage in volume, and the vessel can be filled with more layers, and weighted as before. These methods are suitable for most root vegetables, string beans, cabbage, and cu-cumbers. The large quantities of salt used in these methods must be removed by soaking before the vegetables can be eaten.”


(Water-Glass Method)

Eggs may be kept from 8 to io months, at small expense, by the use of water glass ; and a little timely effort in this respect may prove of great value when the price of eggs is prohibitive. For success in preserving eggs by water glass, a little caution on the following points is positively necessary :

The eggs must be absolutely fresh, preferably not more than 2 days old. (Infertile eggs are the best.) The shells must be clean, and free from the smallest crack. Clean crocks are the best containers, and preferably not over 2 or 3 gallons for family use, as the eggs at the bottom of a large crock are liable to crack, and they will be used last.

Water glass is a pale, yellow, odorless, sirupy liquid, and is known to the chemist as silicate. Use 1 part silicate to 9 parts water distilled, or boiled and cooled. Mix well. Fill the crock half full of the liquid, and place the eggs in it carefully, so as to avoid cracking the shells. The eggs may be added a few at a time, if desired, until the container is about full. The liquid should extend constantly 2 inches above the eggs in the container. Cover the crock, and set in a cool, dark place. If the liquid evaporates, it should be replaced with boiled and cooled water.

For use, rinse in cold water, and use immediately. For boiling purposes, they are good for at least 6 months, and should first have a tiny hole pricked in the large end, to obviate cracking, as the pores of the shell are sealed tight from the silicate. After 7 months, the white becomes thinner, and the yolk membrane more delicate. Nevertheless they are good for cakes, custards, scrambled eggs, and for cooking purposes generally, up to 10 or 12 months.


Fruits are usually slightly acid, and in general, do not support bacterial growth. Thus canned fruits are more commonly fermented by yeasts, if improperly sterilized. The yeast plant is destroyed by heat at less than boiling temperature ; hence the destruction of bacteria may be left out of consideration in the canning of fruits.

Fruit should not be subjected to long cooking, but should be cooked only long enough to insure its preservation. A large quantity of sugar spoils the flavor of the fruit, and is likely to make it less easily digested.


The selection of fruit is one of the first steps toward successful canning. The flavor is not developed until the fruit is fully ripe; but the fruit is at its best for canning and for jelly making just before it is perfectly ripe. In all the soft fruits, the fermentative stage follows closely upon the perfectly ripe stage. Therefore underripe fruit is better than overripe, for canning purposes. This is especially important in jelly making, for the reason that in the overripe fruit, the pectin begins to lose its jelly-making quality. The fruit should be carefully sorted; perfectly ripe fruit and unripe fruit should not be cooked in the same jar.


The quantity of sugar that should be used will vary with the kind of fruit, and somewhat with the locality in which it is grown. The following may be taken as an average; more or less sugar may be used as the case may require.

Apricots, 2 to 2 1/2 quarts water to 1 quart sugar Peaches, 2 1/2 to 3 quarts water to I quart sugar Pears, 3 to 4 quarts water to I quart sugar Plums, 1 to 1 1/2 quarts water to i quart sugar


Prepare the fruit by paring and coring, and blanching such fruits as require blanching, and pack in hot glass jars. Fill with hot sirup, care being exercised so as not to break the jars. Put on the scalded rubber rings, and screw the tops on with the thumb and the little finger. Set the jars on the false bottom of the boiler (water bath), and add water about the same temperature as the jars, to cover them about 1 inch. Bring gradually to a boil, and cook for the length of time given in the table, for the particular kind of cooker used.

Let soft fruits that have not been blanched before being packed into the jars, stand for half an hour after being filled with hot sirup, before cooking, in order that the fruit may absorb water, and they will not break down so easily in the cooking, but will more nearly resemble fresh fruit.


Berries are a very delicate fruit, and break down very easily when canned by the cold-pack method, and because of this, are generally cooked in the open kettle. For each quart of berries, use 1 cup of granulated sugar. Put a layer of berries into a granite dish, sprinkle with sugar, cover with another layer of berries, and so on. If extra juice is desired on the fruit, a little water may be added. Let the berries and sugar stand in a cool place for several hours; then drain off the juice, and bring to a boil. Pour in the berries carefully, and shake the dish once in a while to keep the fruit heating evenly. As soon as it comes to a good boil, draw the saucepan to the edge of the stove, and dip into hot jars with a handled cup. Put the covers on quickly, and screw them on tight. Lay the jars on the side, and turn them once in a while during the cooling; and when they are cold, and set upright, the berries will be evenly distributed through the jar.


Fruit of any kind suitable for canning may be preserved with-out sugar. The sugar can be added when the fruit is used, exactly as is done with fresh fruit. If the fruit when canned is thoroughly ripe, it may be eaten without any additional sugar, and is sweet enough for many tastes. The riper the fruit, provided it is sound, the more sugar, flavor, and nutriment it contains.

Ripe fruits are excellent for making butters. About 1 cupful of sugar to 12 cupfuls of fruit pulp should be used if sweet butter is desired; but the following recipe, if followed, will give a butter which has a sweetness and flavor that are greatly relished, without the use of sugar.


Select overripe fruit, the riper the better, provided it is good. Wash and pit. Put through a colander, rejecting the skins. Do not heat the fruit in the skins, as that extracts a strong acid flavor. Cook the pulp down to the desired stiffness, adding neither water nor sugar. Pour into glass jars, with rubbers on, and screw the covers down tight. Place on the false bottom of a water bath, and into the boiler pour water the same temperature as the fruit, until it reaches about two thirds the height of the jars. Cook for 20 minutes after boiling begins. This last boiling is to make sure that the sterilization of the fruit is complete, and thus insure its keeping qualities. Remove the cover from the boiler, tighten the covers again, invert, and let cool.