KINDS OF SPOILAGE.—As mentioned previously, canned foods spoil either from imperfect processing or sealing. Different organisms growing in preserved foods cause different kinds of spoilage. A discussion [Footnote 123: Adapted from Journal of Home Economics, Vol. X (July, 1918), pp. 329- 331, "A Consideration of the Canning Problem," by Elizabeth F. Genung.] of the various kinds of spoilage follows:
(a) FERMENTATION OR "SWELL."—When canned foods spoil with a production of gas, fermentation of the food is taking place. The visible indications of such spoilage are gas bubbles in the jar and a bulging of the lid of a jar or a distending of the top and bottom of a can. Because of the latter condition, the term "swell" is used in the commercial canning industry to designate this kind of spoilage. When fermentation takes place, the lid of a jar may become loosened instead of bulged.
This type of spoilage is caused by the action either of yeast or of a certain kind of bacterium which thrives best without air. It is usually due to imperfect sterilization. Fermentation can usually be detected by the presence of bubbles of gas in the jar and a loosening of the sealed cover.
(b) Flat Sour is a kind of spoilage in which no gas is formed, but acid is produced, giving the food a sour taste. In some cases of flat sour, a milky deposit appears in the bottom of the jar which can be detected if the container is glass. In other cases, no change in the appearance of the jar and its contents takes place.
Little is known of the kind of organism producing flat sour. Whether or not food thus spoiled is injurious also has not been determined.
Flat sour is probably due to imperfect sterilization.
(c) PUTREFACTION.—When putrefaction takes place, food decays and disintegrates, or decay takes place with the production of a gas of a disagreeable odor. This type of spoilage is readily detected. Food thus affected is unfit for use.
Putrefaction is usually caused by imperfect sealing. It may result, however, from imperfect sterilization.
(d) BOTULISM.—A bacillus termedbotulinussometimes grows on canned foods, especially those rich in protein or lacking in acid. This organism produces a violent poison in the food. But fortunately, the poison may be destroyed by boiling the food for ten minutes. Hence, it is advisable toboilcanned food at least 30 minutes before using. This should be done even though the food is to be served cold. It may easily be cooled after boiling. When there is the least suspicion that food is spoiled, it should be discarded.
Explain why boiled milk keeps sweet for a longer time than uncooked milk.Why do foods need to be sealed to preserve them?
Why does cooked meat "keep" longer than uncooked meat?
JARS FOR CANNED FRUIT.—There are many types of fruit jars. Glass jars rather than metal cans should be used for home canning. Jars should be constructed so that there is no contact of the fruit with metal, hence a jar having a glass cover is desirable. A large opening, simple construction, ease in cleaning, and perfect sealing are characteristics of good fruit jars.
Glass jars should betestedbefore using: Partly fill the jar with water, adjust the rubber and cover, seal, invert the jar. Examine carefully for leakage.
RUBBER RINGS.—Soft, elastic rubbers should be chosen. It is poor economy to use old rubbers. Rubber after usage becomes hard and inelastic; it may cause imperfect sealing and hence decay of the fruit.
In certain processes of canning, it is necessary to subject the jars provided with rubber rings and covers to long periods of boiling or to the intense heat of a pressure or steam cooker. When such a method is followed it is especially necessary that rubber rings of good quality be used. To meet this requirement, the United States Department of Agriculture advises that rubber rings conform to the following:
1. Inside diameter of 2 1/4 inches (for the jar of standard size).
2. Width of ring or flange 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 coarse 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.
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 toboil the jars and rubbersbefore 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.
[Illustration: Courtesy ofMerrill SchoolFIGURE 90—CANNINGFOODS.]
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 quantities of sugar may be used. If the fruit breaks into pieces readily, cook in a thick sirup. The quantity 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 beblanched,i.e.subjected to boiling water or steam. After blanching, the food iscold- dipped,i.e.plunged into cold water. After the preliminary steps, such as washing, paring, and cutting into pieces, foods may beblanchedandcold-dippedas 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 1/4to1cupful 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:
[Illustration: 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 andVegetables," Revised August, 1922.]
TIME OF PROCESSING IN PINT ORFOOD TIME OF QUART JARS IN:BLANCHING (a) (b)Water Bath at Pressure12 degrees F. or Steam Cooker 5 PoundsCookerMinutes Minutes Minutes
Apples,cut in pieces 1 1/2 20 to 30Apricots 1 to 2 30 10Blackberries,Blueberries None 10 to 20 10Cherries 1/4 25 10Currants,Dewberries,Gooseberries None 10 to 20 10Pears 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 largepears.]Peaches 1 or until skinis loosened 20 to 30 10Plums None 20 to 30 12Pineapples None 30 10Raspberries None 10 to 20 10Rhubarb None 20 to 30 10 to 15Strawberries 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 glass jars and the shorter for tin cans.
For altitudes higher than 1000 feet, increase the time of processing 10 per cent for each additional 1000 feet. For very high altitudes 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.
Why should processed jars, covers, and rubbers remain in boiling water until just ready for use?
Why not touch the inside of jars and covers with the fingers?
Why should berries and small fruits be washed before hulling or stemming?
Why should decayed or bruised spots on fruits be removed completely before canning the fruit?
Why is it that the cold pack method of canning is safer from the standpoint of processing than the open kettle method?
Why should the jar containing fruit that is to be processed by the
cold pack method be filled to 1/4 inch of the top with sirup rather than to overflowing?
Why should the covers of jars not be sealed tightly before placing in the kettle or steamer used for processing?
Why is it unnecessary and undesirable to dislodge air bubbles in jars containing food processed by the cold pack process?
When food is processed by immersing the jars in boiling water, why should the water extend above the covers of the jars to a depth of one inch?
EXPERIMENT 93: THE USE OF SUGAR AS A PRESERVATIVE.—Place 2 thin slices of fresh fruit in a sauce dish. Sprinkle one of the slices generously with sugar. Set the sauce dish aside for at least 24 hours. Examine. What change has taken place in the fruit without sugar? What has caused the change? Compare the sugared fruit with that without sugar. What conclusion can be drawn concerning the use of sugar in preserving fruit?
Sugar was mentioned as one of the preservatives used in the preservation of food (seeThe Principles of Preserving Food). Sugar in large quantity is unfavorable to germ life and hence is a most effective preservative.Preservesare made by cooking fruit in a thick sirup as in theMethod of Canning(a) Open Kettle. A large quantity of sugar is desirable as far as preservation is concerned; but for flavor less sugar is usually to be preferred. Only a few fruits are better when preserved with considerable sugar. Fruits best adapted for preserving are strawberries, sour cherries, sour plums, quinces, currants, and raspberries. For preserves, use 3/4 to 1 pound of sugar for 1 pound of fruit. The less quantity of sugar should be used for peaches, plums, quinces, currants, and raspberries; the greater quantity, for strawberries and cherries. Use the quantity of water given inMethod of Canning(a) Open Kettle. Cook and seal as canned fruit.
Jam is made as follows: Clean the fruit. If large fruits are used, pare or peel them and cut into small pieces. If small fruits,—berries or grapes, —are used, mash them. Cook the fruit in as little water as possible. When the fruit is soft, measure it and add the sugar,—use 3/4 to 1 part of sugar to 1 part of cooked fruit. Cook until thick, stirring to prevent burning. Test the thickness by dropping from a spoon. If it falls in heavy drops, the jam is sufficiently cooked. Pour into sterilized jelly glasses. Cover the glasses with clean cloth or paper and set aside to cool and stiffen. Melt paraffin. Pour it (hot) over the cold jam. Allow the paraffin to harden and then cover the glasses with the lids. Wipe the outside of the glasses, label, and store.
Fruit that is too soft or too ripe for canning or preserving may be used for making jam.
Marmalades are made much as jams. However, usually only the pulp and juices of fruits are used. The fruit is first cooked, and the skins and seeds removed before adding the sugar. In Orange Marmalade, the rind is used.
Conserves consist of a combination of two or more fruits. Nuts and other materials are sometimes added. Conserves may be prepared as preserves,i.e.cooking the ingredients with sugar, until thick; or as jam,i.e.cooking the ingredients until tender, then adding the sugar and cooking until thick. It is thought by some that the latter method produces a finer flavor; it makes a product less tough and less sticky. In the special recipes for conserves given in this text, the latter method is followed.
1 dozen oranges 1 grapefruit 6 lemons Sugar
Weigh the fruit, slice it. To each pound of fruit add 1 quart of cold water. Let the mixture stand for 24 hours. Then cook slowly for 2 hours. Weigh the cooked fruit. Add an equal weight of sugar. Cook for 1 hour or until it stiffens. Pour into sterilized jelly glasses, seal, and cover as directed for Jams.
1 dozen oranges 3 pounds sugar 2 quarts rhubarb Rind of 6 oranges
Wash the fruit. Slice the oranges and cut the rhubarb into pieces. (Do not peel the rhubarb.) Cook the oranges and rhubarb for 30 minutes. Add the sugar and cook slowly for 2 hours or until thick. Pour into sterilized glasses. When cool, seal and cover as directed for Jams.
1 pound carrots 3 cupfuls sugar 2 lemons 1/2 teaspoonful salt
Wash, scrape, and chop the carrots. Extract the juice from the lemons. Put the carrots and lemon rinds through a food chopper, cover them with water, and cook until tender. Add the lemon juice, salt, and sugar to the cooked mixture. Cook until it is thickened. Turn into sterilized jelly glasses. Let stand until cool. Then cover with melted paraffin.
Use equal quantities of strawberries and shredded pineapple. Cook the shredded pineapple in the least possible quantity of water. When tender, add the strawberries and cook until they are soft. Measure the fruit and add three fourths as much sugar as fruit and a small quantity of salt. Cook until thick (seeJams). Pour into sterilized glasses. Seal and cover as directed for Jams.
1 quart cranberries 1 1/2 cupfuls water 1/4 pound raisins 1/2 pound California walnuts, chopped 1 orange,—juice and grated rind 1 1/2 pounds sugar 1/2 teaspoonful salt
Wash the fruit. Cook the cranberries in the water until the berries burst. Strain. Add the remaining ingredients and cook 25 minutes or until the mixture is thick (seeJams). Pour into sterilized glasses. When cool, seal and cover as directed for Jams.
1/2 peck grapes 2 oranges,—juice and rind 2 lemons,—juice and rind 1 cupful chopped nuts Sugar 1/2 teaspoonful salt
Wash the fruit. Remove the grapes from the stems; remove the skins from the pulp. Cook the pulp until soft; strain, to remove the seeds. Place the strained pulp and skins in a preserving kettle. Extract the juice from the oranges and lemons, then put the rinds through a food-chopper. Add the lemon and orange juice and rind to the grape mixture and cook for 1 hour. Measure the mixture. Then add an equal quantity of sugar and the nuts and salt. Continue cooking until thick (see Jams). Pour into sterilized glasses. When cool, seal and cover as directed for Jams.
1 pound dried apricots 1 1/2 quarts water Sugar 2 pineapplesor1 large can shredded pineapple 1/2 teaspoonful salt
Wash the dried apricots and soak them in the water. In the water in which they were soaked, cook the apricots until tender. Press through a colander. If fresh pineapples are used, shred them and cook, in as little water as possible, until tender. Combine the cooked fruits and measure. Add 1/2 as much sugar and the salt. Cook until thick (seeJams). Pour into sterilized glasses. When cool, seal and cover as directed for Jams.
1 pound (1 1/2 dozen) plums 1/4 cupful chopped nuts 1 cupful seeded raisins 2 oranges 1 cupful water 1 1/4 cupfuls sugar 1/2 teaspoonful salt
Wash the plums, stone, and cut into pieces. Extract the juice from the oranges. Put the rind through a food chopper. Mix the plums, raisins, orange rind, and water. Simmer until the fruits and peel are tender. Add the orange juice, sugar, nuts, and salt, and continue cooking until the mixture has the consistency of marmalade. Pour into sterilized glasses. When cool, seal and cover as directed for Jams.
How do Preserves differ from Canned Fruit?
How does Jam differ from Preserves?
How does Jam differ from Fruit Sauce?
Why does Jam "keep" better than Fruit Sauce?
Give method of sealing Canned Fruit and method of sealing Jam. Explain why different methods are used.
EXPERIMENT 94: PECTIN IN FRUIT JUICE.—Put a few grapes, slices of apple, or cranberries in a small saucepan, and add enough water to cover and cook until the fruit is tender and soft enough to mash. Strain the cooked fruit through cheese-cloth.
Put 1 teaspoonful of the extracted fruit juice in a saucer, add an equal quantity of alcohol. [Footnote 126: Either grain (ethyl), wood (methyl), or denatured alcohol may be used.Both wood and denatured alcohol are poisonous. If they are used for testing, they should be handled and stored away with caution.] Mix by gently rotating the saucer. Let the mixture stand for 5 minutes. Then examine. What change has taken place in the fruit juice?
The formation of a solid mass in the mixture of fruit juice and alcohol which has stood for 5 minutes indicates that the fruit juice contains pectin,—a vegetable gelatine.
EXPERIMENT 95: PECTIN IN THE INNER PORTION OF ORANGE OR LEMON PEEL.—Cut away the yellow portion from orange or lemon rind. Cut or chop the white portion of the rind in small pieces. Cover with water and soak several hours or overnight. Then cook slowly for 1/2 hour. Strain and set aside to cool. To 1 teaspoonful of this liquid add an equal quantity of alcohol, and proceed as in Experiment 94. Does the lemon or orange rind contain pectin?
THE PRINCIPLE OF JELLY MAKING.—When the juices of certain fruits are extracted and cooked with sugar, the mixture stiffens when cool. This property of stiffening is due to the presence in fruit of two materials,— a certain carbohydrate, calledpectin, and an acid. Pectin is like starch in that it stiffens when cold; but like sugar, in that it is soluble. Not all fruits contain pectin.
Jelly is most easily prepared from fruits which are rich in pectin and contain some acid. Unless pectin is contained in the fruit, the addition of sugar to fruit juice will not cause the juice to jelly. But jelly may be made from a fruit lacking in pectin, if it is combined with a fruit rich in pectin.
Certain fruits contain pectin, but are lacking in acid, hence are not good for jelly making. These fruits can be used for jelly, however, if acid is added.
SELECTION OF FRUITS FOR JELLY MAKING.—For jelly making, choose fruits which contain considerable pectin and some acid. The fruits should be fresh and not over-ripe. Some "green" fruits make fine jelly. Currant, crabapple, grape, apple, and plum are good jelly-making fruits.
If it is desirable to use a fruit containing little pectin, as strawberries, add a fruit rich in pectin, as currants. If about 10 per cent of the fruit which contain much pectin is added to the other fruit, the flavor of the foundation fruit is not much altered.
If it is desired to use a fruit containing pectin but deficient in acid, as sweet apple and quince, add tartaric or citric acid. Since the acidity of fruits varies, no definite quantity of acid can be stated. It has been suggested [Footnote 127: See University of Illinois Bulletin, "Principles of Jelly Making," p. 249.] that enough acid should be added to make the fruit juice about as acid to taste as good tart apples. At least one teaspoonful of acid is required for one quart of fruit juice. Dissolve the acid in the fruit juice, then taste the mixture. If necessary, add more acid to produce the acidity indicated above. Jelly may be prepared from strawberries, peaches, and pears by the addition of these acids, but the flavor is somewhat impaired.
The suggestion has been made also [Footnote 128:Idem, p. 25.] that the inner white portion of lemon or orange peel be used as a source of pectin with fruit deficient in pectin. Remove the yellow portion of the rind, put the white portion through a food chopper, and soak in water for several hours or overnight. Then cook slowly for several hours. Strain out the solid portion. Add the liquid to the fruit juice deficient in pectin and use for jelly making. The rind of lemons and oranges may be dried for use in jelly making. When desired for use, soak and cook as directed above.
Wash and pick over the fruit; remove the stems, but use the skin and seeds and thus retain as much of the fruit as possible. The skin of fruit usually adds color to jelly. If large fruit is used, cut it in pieces. Cook the fruit slowly in water. Use very little water for juicy fruits, such as currants and raspberries,—1 cupful of water to 4 or 5 quarts of fruit. Crush the fruits during cooking.
To cook large fruits requires water. A general proportion ishalf as much water, by measure, as prepared fruit. A little less water may be used for peaches and plums and a little more for winter apples. A fair estimate is 3 quarts of strained juice from 8 quarts of fruit and 4 quarts of water. If the quantity of juice is greater than this, it should be boiled down to 3 quarts before adding the sugar.
When the fruit is cooked until it is very soft, it is ready for straining. For straining, make a bag of double cheesecloth or flannel. Wring the jelly bag out of hot water and suspend it from a strong support. Pour the cooked fruit into the bag and let the juice drip into a bowl. If transparent jelly is desired, do not press the juice through the bag; let the juice drip for several hours or overnight.
Measure the clear fruit juice and heat it. The time of cooking depends upon the per cent of pectin and the acidity of the juice; the more pectin and acid, the less the time of cooking. The time varies from 8 to 30 minutes. Skim the juice when necessary. While the juice is cooking,measure three fourths as much sugar[Footnote 129: The quantity of sugar used in jelly making depends upon the quantity of pectin in fruit juice,—the more pectin, the more sugar. A most satisfactory method of determining the quantity of pectin and consequently the quantity of sugar to use with fruit juice is suggested by the Bulletin of the National War Garden Commission. The test follows: To a tablespoonful of fruit juice which has been boiled and cooled, add 1 tablespoonful of alcohol (see footnote 126.). Mix by gently rotating and then let stand. If a solid mass forms,use equal parts of fruit juice and sugar. If 2 or 3 masses form,use 2/3 to 3/4 as much sugar as juice.If several small solid particles form,use 1/2 as much sugar as juice. If no solid particles form, the fruit juice should be enriched by the addition of some pectin-rich fruit juice.]as fruit juiceand heat the sugar. For currants and green or under-ripe grapes, use equal quantities of sugar and fruit juice. Add the hot sugar to the boiling sirup and cook. The following aretests for sufficient cooking of jelly.
(a) Coats the spoon.
(b) Falls from the spoon in heavy drops. [Footnote 130: Two drops forming side by side along the edge of the spoon has been found to be a reliable test.]
(c) Stiffens when dropped on a cold dish and allowed to cool.
The first two tests are more satisfactory than the last, since the cooking process may be carried too far while the "test-jelly" is cooling.
Seal as Jam or shred paraffin and place it in the bottom of sterilized jelly glasses. Pour the hot jelly into the glasses and set aside to stiffen. Then cover and store. It is well to store jelly in a cool, dry, and dark place. The color of fruit sometimes fades when kept in a light place.
Long cooking of pectin changes it into substances which do not have the property of jellying, hence, make jelly in as short a time as possible. The purpose of heating the sugar is to hasten the process of jelly making. The addition of cold sugar would cool the mixture and thus prolong the process.
The addition of too much sugar is often the cause of unsuccessful jelly making. Crystallization of the sugar from the jelly may result from an excess of sugar.
Thefruit pulp left in the jelly bagshould be utilized. Marmalade may be made from it, or more jelly can be prepared from it. To accomplish the latter, add water to the fruit pulp (enough to cover), mix, and heat slowly until the boiling point is reached. Strain and prepare jelly from the juice. However, more cooking of the juice before the sugar is added is required for the second extraction, since the juice contains so much water. The juice extracted for a third time from most fruits will contain enough pectin for jelly making. It has been found that more desirable jelly can be obtained by this method than by pressing the juice from the bag and thus obtaining what is termed "second quality" jelly.
FRUIT JUICES WITHOUT SUGAR.—Extract the juice from fruit as directed inGeneral Method of Jelly Making. Do not add sugar to the juice. Can it as directed in (a) or (b).
(a) Reheat until the boiling temperature is reached, then pour into sterilized jars. Fill to overflowing and seal.
(b) Place the juice in sterilized jars. Partially seal and place in a water bath having the water reach the neck of the jar. Let it cook at a simmering temperature from 20 to 30 minutes. Remove from the water bath, and seal securely.
In the winter time or when desired for use, this fruit juice may be made into jelly as directed inGeneral Method of Jelly Making, or it may be sweetened, diluted if necessary, and used as a beverage. This method of preserving fruit juice is especially desirable when there is a scarcity of sugar.
[Illustration: FIGURE 92—THE COMPOSITION OF FRUITS AND FRUIT PRODUCTS.(Revised edition.)]
Note the difference in the quantity of carbohydrates in Canned Fruit and Fruit Jelly (see Figure 92). What kind of carbohydrate is present in greatest quantity in these foods?
To what is the difference in flavor of Canned Fruit and Fruit Jelly largely due?
What is the chief difference in the processes of jam making and jelly making?
What is the result if too much sugar is used in jelly making?
What is the result if jelly is cooked too long?
Note the difference in the methods of sealing jams and jellies. Explain.
SPICES AND VINEGAR ARE PRESERVATIVES OF FOODS. Not all spices, however, have equal preservative power. It has been found that cinnamon and cloves aid in food preservation, but that pepper and ginger have very little, if any, preservative power. In the lesson onFlavoring Materials: Food Adjuncts, it was mentioned that spices and condiments should be used sparingly in the diet, hence spiced fruits and pickles should have only occasional use. There is no doubt that lemon juice or other tart fruit juices are better sources of acid-satisfying materials than vinegar.
1/2 peck pears 3 pounds sugar 1 pint vinegar 1/2 ounce ginger root Rind of 1/2 lemon Whole allspice Stick cinnamon Whole cloves
Cut the pears in halves, remove the seeds, and pare. Into each piece of pear stick two or three cloves. Make a sirup of the vinegar and sugar. Divide the cinnamon, allspice, and ginger into two parts, tie in cheese- cloth bags, and add to the sirup. When the sirup begins to simmer, add the pears and lemon rind; bring to the boiling point, remove from the fire, and turn into a stone jar. Cover and stand in a cool place overnight. Next day bring the mixture to the boiling point, again place in the stone jar and stand overnight. The following day heat as before. Do this for five consecutive days. The last day, remove the fruit from the sirup, heat the sirup and evaporate it until there is just enough to cover the fruit. Add the fruit to the hot sirup, heat to the boiling point, then put in stone or glass jars or tumblers.
The pears may be finished in one day as follows: Cook the fruit until tender, then remove it, evaporate the sirup, add the fruit, reheat again, and finish as above. Fruit prepared by the first method has a finer flavor.
12 ripe tomatoes 2 large onions 2 green peppers 2 tablespoonfuls salt 4 tablespoonfuls brown sugar 2 tablespoonfuls ginger 1 tablespoonful cinnamon 1 tablespoonful mustard 1 nutmeg grated 1 pint vinegar
Peel the tomatoes and onions. Chop the onions and peppers fine. Cook all the ingredients together for 3 hours, or until soft and broken. Stir frequently. Bottle and seal while hot. The mixture may be strained before bottling.
20 large ripe tomatoes 6 large onions 4 large stalks celery 3/4 cupful sugar 1 large red pepper 4 tablespoonfuls salt 2 cupfuls vinegar
Chop the vegetables, add the salt and vinegar, and cook for 2 hours. Then add the sugar. Allow it to reach the boiling point again. Turn into sterilized bottles or jars, and seal.
2 dozen small cucumbers 2 dozen small onions 1/2 cupful olive oil 1/4 cupful sugar 1 pint vinegar 1/3 cupful salt 1/4 cupful mustard seed 1 pint vinegar 1 teaspoonful celery seed
Scrub the cucumbers. Cut them (without paring) into thin slices. Wash and cut the onions into thin slices. Mix the salt with these vegetables (to extract moisture), and let the mixture stand over night. Then drain the moisture from the vegetables so that the vinegar may not be diluted.
Mix the remaining ingredients. Pour the mixture over the onions and cucumbers. Mix well, cover, and set aside for a few hours. Then pour into sterilized jars. Fill the jar with liquid. (If necessary, more vinegar may be used.) To drive out the air, place the jars (with covers loosely adjusted) in a water bath at simmering temperature (180 degrees F.) and heat at this temperature for 15 minutes. Remove from the water bath and seal.
TO SEAL BOTTLES.—Melt together, over hot water, equal parts of shoemaker's wax and resin. When liquefied, dip the tops of corked bottles into it. Corks in bottles may be dipped also in hot paraffin. Dip several times.
What is the objection to excessive use of spiced foods?
Name some substitutes for pickles. Why is an excessive or continuous use of pickles objectionable in diet?
MICROORGANISMS IN THE SPORE FORM.—Many microorganisms are destroyed by heating them for a few minutes to boiling temperature. However, some microorganisms have a peculiar power of retaining life under most adverse conditions. When subjected to extreme heat or cold, intense drying, or when there is lack of food, certain microorganisms assume a spore form,i.e.they cease growing and reproducing, and are able to undergo conditions which would readily kill microorganisms in the active form. Some microorganisms in the spore form are able to resist the temperature of boiling water for an hour or longer. Then as soon as the adverse conditions mentioned above are removed, the microorganisms assume active form and begin to grow and reproduce. In the growing state, their destruction is not so difficult.
Some of the microorganisms in certain foods, especially vegetables and fruits grown in a dry season, are capable of spore formation. When microorganisms in spore form do exist in foods that are to be canned, or the microorganisms change into spore form during the canning process, the microorganisms may not be destroyed by the time the ordinary process of canning is completed. If such is the case, when the canned foods are cooled and the conditions are favorable for growth, the microorganisms assume active form, begin to grow, and cause the decomposition of food. Twenty-four hours is sufficient time for the microorganisms to change from the spore to the active form. Hence the canned foods must be heated again, if they are to be preserved. For foods difficult to process (for the reason given above) processing should be carried on for three successive days. This is calledintermittent processing.
Destruction of microorganisms in the spore form can be accomplished in a short time by subjecting them to very intense heat. In canning factories this is done by processing at a temperature higher than that of boiling water. In the home this may be accomplished by processing in the pressure cooker. According to one authority processing intermittently,i.e.on three successive days, does not insure satisfactory processing of materials containing spores.
SINGLE PERIOD AND INTERMITTENT PROCESSING.—The acid of tomatoes and fruits aids in the destruction of microorganisms. Hence intermittent processing is unnecessary for these. Processing tomatoes and fruits in a hot water bath for one period has proved very satisfactory and certain.
There is some question, however, regarding the safety of canning all vegetables by one period of processing in the water bath at 212 degrees F.,especially in regions where botulism is known to occur and where Foods cannot be stored in a cool place. In Farmers' Bulletin 1211, "Home Canning of Fruits and Vegetables," revised August, 1922, one period of processing in the water bath at 212 degrees F. is not advised in climates where the storage conditions are trying for the following vegetables: corn, beans, asparagus, okra, spinach and other greens, and peas (especially if at all mature). For processing these vegetables, a higher temperature than that obtained in the boiling water bath is recommended. Processing at a high temperature (from 228 degrees F. to 250 degrees F.) can be accomplished conveniently by means of apressure cooker. This is especially recommended for vegetable canning in high altitudes and in localities where botulism has occurred.
It is thought that in some places the above mentioned vegetables may beprocessed intermittentlywith safety. For vegetables difficult to can, pint jars only are recommended for both intermittent and single period processing in the water bath. Heat penetrates more rapidly to the center of the small jars than to the center of the large jars.
SELECTION AND PREPARATION OF VEGETABLES AND CANNING.—Young vegetables, especially those that have grown quickly, are most desirable for canning. If possible, vegetables, especially corn, should be canned immediately after picking.
Vegetables for canning should be thoroughly washed, pared, scraped, or cut into pieces in the same manner as when they are cooked and served immediately. If the vegetables vary in size, it is well to sort them and fill jars with those of uniform size. If there is much difference in ripeness, sort the mature and young vegetables.
METHOD OF CANNING VEGETABLES.—The method of canning vegetables for asingle perioddoes not differ greatly from the method of canning fruits. The chief difference is that jars containing fruit are filled with sirup, while those holding vegetables are filled with water and salt is added. Blanch and cold-dip vegetables as directed previously, for the length of time given. Greens and vegetables of delicate flavor are blanched most successfully by steaming either in a colander placed over boiling water or in a steamer. (Steaming greens prevents the escape of volatile oils and other materials.) Pack the vegetables in jars to within 1/2 inch of the top. It is well not to pack spinach and other greens too solidly in jars. Since lima beans, corn, and peas swell during processing, they should be packed only to about 1 inch of the top of the jar. To each jar add salt,—1 teaspoonful to each quart jar. Fill each jar to 1/2 inch of the top with boiling water. Put a new rubber on the jar, partly seal the cover, and proceed as directed for fruit (see Table below for the length of time for processing).
When vegetables are processedintermittently, jars with glass tops and spring clamps are recommended. In processing vegetables for three successive periods, the same method of processing and sealing is followed as for the single period. At the beginning of the second and third periods, raise the clamps of the jars to allow for expansion, then fasten the clamps at the close of processing period (see Table for the length of time of processing on each of the three successive days).
TABLE FOR CANNING FRESH, SOUND, AND FIRM VEGETABLES BY ONE PERIOD OFPROCESSING [Footnote 131: Adapted from Farmers' Bulletin 1211. RevisedAugust, 1922.]
TIME OF PROCESSINGTIME OFVEGETABLE BLANCHING OR (a) (b) Steam PressureWater (Pressure Cooker)COOKING Bath at (1) 5lb (2) 10lb (3) 15lb212 deg. F. 228 deg. F. 240 deg. F. 250 deg. F.Minutes Hours Minutes Minutes MinutesAsparagus 4 - - 30 to 40Corn 1 to 5 - - 90 60 to 90Lima beans 3 to 5 - - 45 to 60Okra 6 to 8 - - 30Peas 3 to 8 - - 40 to 50Spinach 4 in water or15 in steam - - 90 35String beans. 3 to 5 - - 40 to 50Tomatoes 1 to 1 1/2 toloosen skins 1/2 15 10
[Footnote for Asparagus: Scrape off tough outer skin ofasparagus. Tie into bundles for blanching. Blanch tough ends 2 minutes and entire bundle 2 minutes longer.]
[Footnote for Corn: Blanchcornon the cob, then cold dip and cut from the cob. For each pint jar, use 1 pint of cut corn, 1 cupful boiling water, and 1/2 tea-spoonful each of salt and sugar. Cook the mixture in a saucepan until it boils and pour immediately into a hot, sterilized jar.]
[Footnote for Okra: Cold dipokrainsaltwater (1 tablespoonful salt to 1 quart water).]
[Footnote for Spinach: To loosen grit, coverspinachwith scalding water, let stand 1 or 2 minutes. Then wash in several cold waters. Do not cold dip after blanching.]
[Footnote for Tomatoes: Packtomatoeswhole in jars, then fill the jars with cooked and strained tomato pulp. Tomatoes cut into pieces may be packed closely in jars. When this is done, no liquid need be added.]
NOTE.—Processing in the hot water bath is not advised for non-acid vegetables such as asparagus, corn, lima beans, okra, peas, spinach, and string beans.
Count time of processing in a water bath after the water boils.
When two different times of processing are given, use the longer time for quart glass jars, the shorter time for tin cans.
If the jar is packed tightly, increase the time of processing.
For altitudes higher than 1000 feet, increase the time of processing 10 per cent for each additional 1000 feet. For very high altitudes, the pressure cooker rather than the hot water bath should be used.
TIME TABLE FOR CANNING VEGETABLES BY INTERMITTENT PROCESSING [Footnote 132: See statements previously]
VEGETABLE TIME OF TIME OF PROCESSING IN WATER BATHBLANCHING AT 212 F. 12 TO 18 HOURINTERVALS BETWEEN PERIODS(a) First Day (b) Secondand Third Day
Asparagus 10 to 15 60 60Corn 5 to 10 90 90Lima Beans 3 to 5 90 90Peas 5 90 90String Beans 3 to 5 90 90
[Footnote 133: (For Asparagus, Corn, and Lima Beans) Process inpint jars only. See footnotes for Asparagus and Okra, above.]
USE OF CANNED VEGETABLES.—Open the can and if it is tin, empty its contents at once. If the vegetable is surrounded by liquid, use the water in cooking the vegetable, as it contains valuable materials. There are some who contend, however, that the flavor of certain vegetables such as peas and string beans is improved if the vegetable water is drained from them and they are cooked in fresh water. If this is done, the vegetable water should not be wasted. It should be used in making soup or sauce. If possible, let the vegetable stand exposed to the air for an hour or longer.
If the vegetable is to be served plain, turn into a saucepan. Cook in its own liquor at boiling temperature, for at least 30 minutes. (Cooking at boiling temperature for this length of time is advised to remove any possible danger of botulism.) When cooked, the liquid should be almost entirely evaporated. Add butter, salt, and, if desired, a very little sugar, and serve hot.
A White Sauce may also be used with a vegetable that has been heated as above.
Explain why vegetables (except tomatoes) are more difficult to can successfully than fruits.
What foodstuffs does the water in which vegetables are canned contain? From this explain why the water should not be drained from vegetables when removing them from the cans.
What is the purpose of cooking canned vegetables at boiling temperature?
ADVANTAGES OF DRYING FOODS.—While preserving foods by drying does not take the place of canning foods and storing them in jars or cans, it has certain advantages, viz.:
1. Little storage space is required for dried foods.
2. Dried foods can be stored in containers that cannot be used for canning.
When foods are dried, they may be reduced in bulk as much as 90 per cent; for example, 10 pounds of fresh food may be reduced to 1 pound of dried food. By this reduction no food value is lost, and the flavor is not greatly changed.
Dried foods may be stored in paper bags and boxes which are much less expensive containers than glass jars or tin cans. Hence if space is limited and glass or tin containers are difficult to secure or are expensive, drying may prove a very satisfactory method of preserving food.
METHODS OF DRYING AND DRIERS.—Food may be dried by:
1. Sun.
2. Steam (placing food on a specially constructed tray (see Figure 93) which is heated with steam).
3. Stove or oven drying (placing food above a stove or in the oven).
4. Fan drying (placing an electric fan near the food).
A combination of these methods, especially the two latter, is often used in drying foods.
Plates or dishes may serve as driers when the drying is done in the oven. Trays for drying may be constructed at home or they may be purchased. Most of them consist of a wood or metal frame over which wire netting is tacked. Single trays or a series of trays one placed above the other may serve as driers. When drying is accomplished by heat from a stove, the drier is hung over a stove or it rests on the top of the stove. In the latter case, it is necessary that the frame of the tray be constructed so that the bottom tray does not rest directly on the stove. In case the drying is done over a kerosene stove, the bottom of the tray must be of tin or galvanized iron to protect the food from kerosene fumes. The lowest tray must be placed at least 4 inches above the metal bottom.
SELECTION AND PREPARATION OF VEGETABLES FOR DRYING.—To secure the best results, select mature but fresh vegetables. They should be in good condition, free from blemish.
Certain foods, such as berries, cherries, peas, lima and shell beans, are dried whole. Most vegetables should be cut into slices from 1/8 to 1/4 inch in thickness. The slicing may be done with a paring or kitchen knife, or it may be done by means of a slaw-cutter or a rotary chopper. Foods are sometimes cut into pieces for drying by means of the food chopper. It is necessary that all knives and cutting devices be clean. There should be no discoloration of the vegetable from the cutting utensil. It has been found advisable to blanch most vegetables before drying. The method of blanching given previously can be used in drying vegetables as well as canning them. Foods are not cold-dipped, however, after blanching when they are to be dried. Fruits are usually not blanched before drying.
METHOD OF DRYING FOODS.—Place the prepared food on drying trays. Unless the drying is done in the oven, cover the food with cheese-cloth. If possible, tack the cloth to the frame so that no dust or insects can come in contact with the food. Stir or turn foods once or twice a day while they are drying. This is especially necessary when foods are dried in the sun.
If the food is to be dried in the sun, place the tray containing the food in the sun, where there is a breeze. If it rains, take the trays indoors. Also bring the trays indoors just before sunset.
If food is to be dried by means of steam, a special device is needed (see Figure 93). The device consists of a large pan for holding water and a hollow tray. The under surface of the tray has an opening about the size of the diameter of the pan. To this opening is fastened a collar which fits snugly into the pan. The pan filled with water is placed over a burner. When the water boils, the steam rises and fills the hollow tray and escapes by means of the small pipe in the upper surface of the tray. The food is placed on the upper surface and is dried by steam heat.
If the food is to be dried in the oven, place the food on suitable trays. Oven drying is much more satisfactorily done if the oven is provided with a thermometer. The temperature for drying foods is much less than that of boiling water,—it varies from 115 degrees to 175 degrees F. It is often necessary to keep the oven door open so that the temperature does not become too high.
[Illustration: FIGURE 93.—-DRIER FOR VEGETABLES OR FRUITS.]
If food is dried over a stove in a series of traysone placed above the other, the position of the trays should be changed so that the food may be uniformly dried.
If food is dried by means of an electric fan, the fan should be so placed that the current of air is directed along the trays lengthwise. The drying will be most rapid nearest the fan; hence it is necessary to change the position of the tray or of the food every few hours. Foods may be dried in less than 24 hours by means of an electric fan. A few foods such as sliced string beans may be dried in a few hours. Before drying by means of a fan, food should be blanched. It is also necessary to heat food dried in this way in an oven at 180 degrees F. for 10 or 15 minutes before storing.
Testing for Sufficient Drying and Conditioning.—The time for drying varies with the method of drying and the kind of food. A definite time of drying cannot be stated. There are some tests which may be applied in determining when a food is sufficiently dried. The following is quoted from the Bulletin of theNational War Garden Commission, Victory Edition, p. 22:
"When first taken from the drier, vegetables should be rather brittle and fruits rather leathery and pliable. One method of determining whether fruit is dry enough is to squeeze a handful; if the fruit separates when the hand is opened, it is dry enough. Another way is to press a single piece; if no moisture comes to the surface the piece is sufficiently dry. Berries are dry enough if they stick to the hand but do not crush when squeezed."
When the food is judged to be sufficiently dried, it should be placed in boxes or bowls and covered with clean cloths. The dried foods should be stirred or poured from one container to another once a day for 10 days or two weeks. If at the end of this time the food is found to be moist, it must be subjected to the drying process for a short time. After the second drying, it should be treated as directed above. If the food is observed for several days and found to be dry, it may be stored away. This process of testing and making them sufficiently dry after removing from the drier is termedconditioning.
Select such sweet corn for drying as you would for immediate table use. Blanch the corn (on the cob) for 8 to 12 minutes in boiling water. Drain thoroughly. Then cut the corn from the cob as directed in Lesson IV. Dry by subjecting to a temperature of 130 degrees F. gradually increased to 140 degrees F. Stir the corn often. It is sufficiently dried when it is hard and semi-transparent.
(Adapted fromBulletin of the National War Garden Commission, VictoryEdition.)
TABLE FOR BLANCHING AND DRYING [Footnote 134: From Bulletin of theNational War Garden Commission, Victory Edition]
The following table shows blanching time for vegetables and the temperatures to be used in drying by artificial heat.
VEGETABLES BLANCHING TEMPERATURETIME (FAHRENHEIT)Minutes Degrees
Beets 2 120 to 145Cabbage 3 to 4 115 to 135Carrots 2 120 to 145Cauliflower 4 to 6 120 to 130Celery 2 to 3 135Figs 120 to 140Garden peas 3 to 5 115 to 140Green string beans 5 to 8 130 to 145Lima beans 3 150Okra 3 115 to 135Onions 140Parsnips 2 120 to 145Potatoes 2 to 3 125 to 150Prunes - 130 to 175Pumpkin and winter squash 3 to 6 135 to 160Spinach 2 130Summer squash 3 to 6 135 to 160Sweet corn 8 to 12 130 to 140Sweet potatoes 6 to 8 145 to 165Tomatoes 1 1/2 120 to 140Turnips 1 to 2 135 to 165Wax beans 3 150
Fruits
Apples 130 to 175Apricots 130 to 165Berries 130 to 155Cherries 120 to 150Peaches 130 to 165Pears 130 to 175Plums 130 to 165
Under what conditions do you think it would be advisable to dry foods rather than can them?
Name the advantages of dried over canned foods and the advantages of canned over dried.
From what you have learned regarding the cooking of dried fruits and dried peas and beans, how would you cook home-dried vegetables?
Give a reason for each step of the process.
Why is it necessary to stir foods occasionally while drying?
Why is oven drying of foods much more satisfactory when the oven is provided with a thermometer?
Explain why it is necessary to condition dried foods before storing.