2. Width of ring or f.l.a.n.g.e from 1/4 to 12/32 of an inch.
3. Thickness of 1/12 of an inch.
4. Tensile strength sufficient to "stretch considerably and return promptly to place without changing the inside diameter."
5. Firm enough so that no crease or break shows after it has been tightly folded.
SELECTION AND PREPARATION OF FRUIT FOR CANNING.--Select solid, and not over-ripe, fruit. It is better to have underripe than over-ripe fruit.
Fresh fruits--if possible picked on the same day they are to be used--are desirable for canning.
Most fruits should be washed before using. Quinces should be rubbed with a coa.r.s.e towel before they are washed. Berries and small fruits should be washed before they are hulled or stemmed. Most small fruits contain so much water that it is not necessary to add water for cooking. Hence such fruits should be drained thoroughly after washing. If there are any decayed or bruised spots on fruit, the damaged portion should be removed completely.
Peaches and tomatoes may be peeled instead of pared. This is done by placing the fruit in a wire basket and then immersing the basket in a kettle of boiling water for 3 minutes. Remove the basket of fruit from the hot water and plunge it for a moment in cold water. Drain, then peel the fruit. If desired, cut into halves, quarters, or slices. After fruit is peeled or pared, it can be kept from discoloring by covering with cold water.
METHODS OF CANNING FRUIT
Several methods may be used for canning fruit:
(_a_) OPEN KETTLE.--This method consists of cooking the fruit in water or sirup and pouring it into jars and sealing. The entire process of sterilization takes place in the kettle before the food is poured into the jars. Hence the name of the process,--_Open Kettle_.
For this method it is necessary to _boil the jars and rubbers_ before placing the food in them. This is done as follows:
Fill and surround jars with cold water. Cover lids and rubbers with cold water. Gradually heat the water and allow it to boil for at least 15 minutes. Allow the jars, covers, and rubbers to remain in the boiling water until just ready to use them. Do not touch the inside of the jars and covers with your fingers. Immerse spoons, cups, knives, skewers, or knitting needles used for testing fruits, in boiling water before using them in contact with the foods. If corks are used for sealing bottles, scald them also.
[Ill.u.s.tration: Courtesy of _Merrill School _ FIGURE 90--CANNING FOODS.]
If small juicy fruits are preserved by the open kettle method, no water should be added. Add the sugar to them and allow them to stand until some of the juice is drawn from them, then cook.
If tough fruits are canned by this method, first steam, then cook in sirup, or first cook them in clear water, add the sugar, and finish cooking.
Fruit may be canned with or without sugar. Usually some sugar is used.
However, some housekeepers contend that the fresh-fruit flavor is retained better by reheating the fruit and adding the sugar just before it is served. Different quant.i.ties of sugar may be used. If the fruit breaks into pieces readily, cook in a thick sirup. The quant.i.ty of water used with the sugar varies with the juiciness of the fruit. _For each pound of fruit use from 1/2 to 1 cupful of sugar with from 1/8 to 1 cupful of water_.
After cooking the fruit, adjust the rubber on the sterilized jar, fill the jar (to overflowing) with the hot fruit and sirup, cover at once, and seal. Invert the can and let it stand until cool.
(_b_) COLD PACK.--This method is followed by placing the prepared food in a clean, tested, hot jar, covering the food with water or sirup, adjusting the rubber ring and cover to the jar, and processing both the jar and its contents in boiling water or steam.
Before placing the food in the jar, it may be _blanched_, _i.e._ subjected to boiling water or steam. After blanching, the food is _cold- dipped_, _i.e._ plunged into cold water. After the preliminary steps, such as washing, paring, and cutting into pieces, foods may be _blanched_ and _cold-dipped_ as follows:
Place the food in a cheese-cloth bag or in a wire basket and immerse it in boiling water. Certain fruits are allowed to remain in the water from 1 to 5 minutes (see Table). (The time is dependent upon the kind of fruit.) Then remove the product from the boiling water, dip it immediately in cold water, remove at once, and drain for a few minutes. These two processes are used for large firm fruits. Berries and all soft fruits are canned without blanching and cold-dipping.
Whether the fruit is blanched and cold-dipped or not, place it in hot jars to 1/2 inch of the top. If a sirup is desired, it may be made by using 1/4 _to_ 1 _cupful of sugar for each quart jar with from 2 to 3 cupfuls of water._ Adjust a new, wet rubber on the jar; fill the jar to 1/4 inch of the top with sirup or with boiling water. Place the cover on the jar, but do not seal it tightly. If a screw top jar is used, screw on the lid by grasping it with the thumb and little finger. If the jar has a bail top, adjust the top bail only,--not the lower bail. Then process the jars and their contents by placing in:
[Ill.u.s.tration: FIGURE 91.--RACK FOR HOLDING JARS. Note that the rack is shaped to fit a wash boiler.]
(1) Kettle or clothes boiler provided with a rack (see Figure 91) or some sort of false bottom such as strips of wood, straw, paper, or wire-netting of one half inch mesh.
(2) Steam cooker (see Figure 18).
(3) Pressure cooker (see Figure 17).
If the kettle or wash boiler is used, rest the jars on the rack in the container, fill the latter with enough hot water so that it extends to a depth of one inch above the covers of the jars. Then boil the water. Count the time of processing when the water begins to boil. Keep the water at boiling temperature for the length of time given in the Table below.
If the steam cooker is used, place the filled jars in the cooker and steam for a few minutes longer than when the jar is immersed in boiling water (see Table below).
If the pressure cooker is used, process according to the length of time stated in the Table given below.
After sterilizing fruit by any of these methods, remove the jars from the container, seal, invert, and set them aside to cool in a place free from draft. When cool, wash the outside of the jars, and label. Store in a cool, dark cupboard. Wrapping each jar in paper before storing is advised.
Bail top jars may be tested for perfect sealing by loosening the top bail, and lifting the jar by grasping its lid with the fingers. If the jar is securely sealed, the lid will not come off, because of internal suction.
In case the lid comes off, remove the rubber, replace it with a new, wet one, adjust the cover and again process for at least 1/3 of the original processing period or not less than 10 minutes.
A DISCUSSION OF METHODS OF CANNING.--(_a_) While the open kettle is not as safe a method of canning as the cold pack from the standpoint of perfect processing, it is desirable for small watery fruits, especially strawberries, since evaporation of some of the water takes place. It is also generally used for fruits preserved with much sugar, such as preserves, jams, conserves, etc. Many housekeepers find this method desirable for canning tomatoes and beets. The skins may be removed from the latter after cooking, thereby losing less coloring of the vegetable.
(_b_) The cold pack method of canning is very satisfactory for most fruits and all vegetables. It is especially desirable for whole fruits or for fruits in large pieces. The shape of the fruit may be preserved better by this method than by the open kettle process. It is also a safer method as far as satisfactory processing is concerned. Many housekeepers find it easier than the open kettle method.
The blanching and cold-dipping of vegetables and fruits which may be one of the steps in the cold pack method is thought to accomplish several things:
1. To remove objectionable acids and flavors.
2. To make the foods more pliable for packing in the jars.
It was formerly thought that blanching and cold-dipping of vegetables destroyed some of the bacteria and aided in processing the food. Recent experimentation shows that these processes do not affect the bacteria and have no value as far as the preservation of the food is concerned.
TABLE FOR CANNING FRUITS BY ONE PERIOD OF PROCESSING [Footnote 124: Adapted from Farmers" Bulletin 1211, "Home Canning of Fruits and Vegetables," Revised August, 1922.]
TIME OF PROCESSING IN PINT OR FOOD TIME OF QUART JARS IN: BLANCHING (_a_) (_b_) Water Bath at Pressure 12 degrees F. or Steam Cooker 5 Pounds Cooker Minutes Minutes Minutes
Apples, cut in pieces 1 1/2 20 to 30 Apricots 1 to 2 30 10 Blackberries, Blueberries None 10 to 20 10 Cherries 1/4 25 10 Currants, Dewberries, Gooseberries None 10 to 20 10 Pears 4-8 in boiling sirup 20 to 30 10 [Footnote 125: Do not cold dip after blanching in boiling sirup.
Use the longer time of processing in the water bath for large pears.]
Peaches 1 or until skin is loosened 20 to 30 10 Plums None 20 to 30 12 Pineapples None 30 10 Raspberries None 10 to 20 10 Rhubarb None 20 to 30 10 to 15 Strawberries None 10 to 20 10
NOTE.--Use only fresh, sound fruits for canning.
Do not begin to count the time of processing in a water bath until the water reaches the boiling point.
When different times of processing are given, as 20 to 30 minutes, use the longer time for quart gla.s.s jars and the shorter for tin cans.
For alt.i.tudes higher than 1000 feet, increase the time of processing 10 per cent for each additional 1000 feet. For very high alt.i.tudes it may be best to use a pressure cooker for certain fruits.
If fruits are packed tightly, time of processing should be increased.
DISCUSSION OF THE DIFFERENT DEVICES USED IN THE COLD PACK PROCESS.--(1) The kettle or wash boiler provided with a rack is an inexpensive device.
It is satisfactory for processing fruits and acid vegetables; there is a question whether non-acid vegetables may be processed in the hot water bath even though they are processed on three successive days. It is thought by some that the flavor of foods canned at low temperature, _i.e._ not above 212 degrees F., is superior to that canned at a higher temperature.
(2) The steam cooker is a convenient and satisfactory equipment to use for canning fruits and some vegetables. It is more expensive, however, than the kettle having a rack, but less fuel is required when using it.
(3) The pressure cooker is the most satisfactory from the standpoint of processing. It is especially satisfactory for vegetables and meat, since a much higher temperature than that of boiling water is maintained during the processing period. The higher temperature also makes it possible to process foods in a shorter time. However, it is thought by some that the flavor of foods canned above 212 degrees F. is inferior to that canned at a lower temperature. Moreover, the pressure cooker is a more expensive device than either of the other two.