Chapter III: Part 4: Home Food Preservation (2)

When filling jars, you will find the jar-filling funnel easy to manage. This makes it possible to avoid spills of seeds, bits of food, or sirup that could prevent sealing. But even when using a funnel you still need to wipe the jar rim.

Prepare the lids and sealing of jar according to the manufacturer's directions. When using a flat metal lid, place the composition side on the rim of the jar. Add the ring band and screw it down until firm, but not hard enough to cut through the sealing compound. The lid will have enough "give" to let air escape during processing. This is called venting and means heating to remove air from jars.

When using porcelain-lined zinc caps, fit the wet rubber ring on the jar shoulder, but do not stretch it more than necessary. Screw the cap firmly and turn it back ¼ inch.

Use a jar lifter or tongs and place the filled jars on the rack in the canner. Fill and place jars in the canner one at a time to keep jars as hot as possible while filling the canner.

Water Bath

Before you begin preparing the food, fill the water bath canner half full of hot water. This permits water to heat while you prepare the food. Put a large kettle or teakettle of water on to boil. The water should be boiling when hot-pack food is put into the canner.

Place raw-pack jars in water that is hot (180° to 190° F), just below boiling. Then bring it to a boil after adding jars.

As the rack of jars is lowered into the water, the water level will rise. If more water is needed to have the jars completely covered by 2 inches of water, add boiling water.

Prepare only enough jars of food at one time to fill the canner. Work rapidly, allowing as little time as possible between filling and closing the jars and getting them into the canner.

Start counting processing time as soon as the water in the canner reaches a gently rolling boil. Put the lid on the canner. Set your timer or clock and make a written note of starting time and final time. Keep the water boiling all during the processing period. If water boils down, add boiling water sufficient to keep it at the required height. When pouring water, avoid letting it hit tops of the jars.

Process for the recommended length of time. Do not cut processing time.

Pressure Canner

Follow the manufacturer's directions for operation of your pressure canner before, during and following processing. Supplement these directions with information in U.S. Department of Agriculture or Extension publications.

Count processing time as soon as the pressure reaches 10 pounds or the proper pressure adjusted for altitude. Be sure to hold pressure steady.

At end of the processing time, remove the canner from the heat. Allow the canner to cool until the gage registers zero to avoid breakage of jars and loss of liquid from jars. After a minute or two, open the petcock gradually and remove the cover. If a weighted gage is used, nudge the weight slightly. If no steam escapes, pressure is down. Tilt the far side of the lid upward so steam escapes away from your hands and face. Because food in the jars may be boiling vigorously, leave jars in the canner about five minutes and then remove them.

After Processing

When you remove hot jars from the canner, use a jar lifter, or protect your hands with cooking mits, pot holders or canvas gloves. Set the jars upright to cool on a rack, such as a cake rack, or a bread or cutting board, with double layers of dry cloth or newspapers beneath the jars. If jars are placed on a cold surface or wet cloth, the difference in temperatures may cause the glass to crack.

Avoid placing jars in a draft, but leave two or three inches between them so air can circulate freely. Avoid further tightening of lids that have sealing compound, since this usually breaks the seal--unless the lid manufacturer states it is safe to tighten.

If your processing temperature was not held steady and liquid boiled out in processing, do not open the jar to add more. Leave the sealed jar just as it is.

Do not cover jars because this slows down cooling and food continues to cook. If you have an air conditioning vent that will direct cold air on jars, cover the vent during this canning session.

After 12 hours, check the seals. The vacuum may cause a loud snap of the two-piece vacuum seal while it cools, which is an indicator of an airtight seal. If the center of the lid holds down when pressed and the lid does not move, it is sealed.

Tap the center of the lid with a spoon--a clear, ringing sound indicates a good seal; a thudding sound indicates the possibility of an imperfect seal.

If there is a sealing failure, you will need to reprocess the jars. Remove the lid, heat the food and liquid, fill a clean jar and use a new lid. Process the full length of time. If only a few jars did not seal, you may elect to refrigerate and use the food within a day or two or freeze it.

Once the jar is sealed, allow it to set until cold. Then remove the screw ring band, wash and store in a dry place for reuse. For safety make a routine check of canned foods each month.

Label and Inventory

Write name of product and date canned on a gummed label or the lid of each jar with a felt tip pen. Keep a record of food canned, date, number of quarts or pints, and a place for you to check them off as you use them. This can be your guide for next year's preservation plan. Use food preserved for the current year, readying a storage place for next season's garden produce.

Canned foods stored in a dry, dark, cool temperature (70° F or below) will retain good eating quality for a year. Home canned foods stored in a warm place near direct sunlight, hot pipes, above a range or refrigerator, or in kitchen cabinets may lose some eating quality within a few weeks. Dampness may corrode lids and cause leakage so that the food spoils.

The main cause of spoilage in canned foods is improper processing. Bulging jar lids, or a leak, may mean gas is present and the food spoiled.

Before opening home canned foods, wash jars and lids and carefully inspect the jars. Bacteria, yeasts and molds should have been destroyed if the food was properly processed.

When you open the container, look for such danger signs as spurting, cloudy or frothy liquid, an "off" odor, deterioration, or slimy texture. A foamy or murky appearance and patches of mold are visible signs of spoilage. That ordinary looking mold on home-canned food may indicate the presence of a much more deadly problem: botulism.

Destroy food if any of these signs are obvious; discard out of reach of humans and animals.

The odor in good jars of food should be pleasant and characteristic of the product. Do not use food which looks or smells bad, or if there is any doubt as to its safety.

All low-acid, home-canned food should be boiled 10 to 20 minutes to insure destruction of botulism-causing toxin for added safety. Heating denatures the toxin so that it does not react with the body. Never taste home canned food before cooking it.

Successful results largely depend upon the accuracy with which up-to-date directions are followed.

Safety is best assured when you exercise special care as you prepare and pack food into canning jars, fitting jars with properly pretreated lids, and heating jars of food to a high enough temperature for a sufficient length of time to kill micro-organisms that cause spoilage.

A Primer on Home Freezing for the Beginner

_by Charlotte M. Dunn_[5]

Every homemaker knows that meals must be planned to get the most out of the food dollar and to provide the family with a well-balanced diet. The freezer, more than any other household appliance, can help secure these results. The more you learn how to use it in relation to your own family, the greater the returns.

Freezing is a quick, convenient and easy way to preserve foods in the home. Plan ahead to manage your time and energy for preserving food directly from harvest. Freeze limited amounts at one time so the work is spread over several days of picking, rather than squeezed into one long tiring period of time. Be practical about what you attempt.

Your own observation has taught you that some foods "spoil" more quickly than others, so the rate of speed at which they must be frozen varies with their individual temperaments. A good rule for home freezing is: two hours from garden or orchard to container, and the faster the better!

Most food that is highly perishable at normal temperatures can be quick frozen. Even delicate fruits and vegetables can be frozen, with only a few exceptions such as tomatoes (stewed tomatoes can be frozen) and those vegetables that lose crispness such as radishes, celery, cucumbers and salad greens.

Decide what you will freeze on the basis of availability of foods, family needs and taste, freezer space, cost of freezer storage, and availability of alternate methods of storage.

It is essential to start with high quality raw material. As garden foods mature, process without delay. Quality of the frozen food will be only as good as the quality of the food before freezing. Freeze foods at their peak of eating quality to preserve flavor, texture, and appearance as near those of the fresh product as possible.

Do not ignore details of the recommended procedures for preparing foods for freezing. Seemingly unimportant steps can make the difference between a low quality and a superior frozen product.

Before you begin freezing foods at home it's important to know exactly which process to use and what the process is doing to the food.

Micro-organisms grow on food, causing it to spoil. The common growths are simple yeasts, molds, and bacteria. Because these micro-organisms are everywhere--in the air, water, soil and on all surfaces they contact--they naturally occur on all foods. Storing and preserving foods properly controls or inhibits the growth of micro-organisms, thus maintaining both quality and safety of the food.

Cleanliness and sanitary methods are as important in handling foods for freezing as in preparing them for immediate use.

All foods contain chemical substances called enzymes. They are essential to life, and continue their chemical activity after the fruits and vegetables mature or are harvested.

If allowed to work after a food reaches its peak of maturity, enzymes destroy the food's physical properties, thus changing its color, flavor and texture.

When perishable food is not preserved by one of the recommended ways, enzymes within the cells of the food continue to live and cause spoilage.

What Freezing Does

Freezing and storage even at very low temperatures will not inactivate any of the common enzymes. At 0° F, the recommended temperature for storing frozen foods, enzymes are not inactivated but only slowed down. In two to three months they will produce off-odors and bad taste. This temperature only checks the growth and reproduction of destructive bacteria. The faster a food is properly prepared frozen, the sooner both enzymes and bacteria are rendered harmless.

Just about every kind of food you or I will freeze contains moisture or water, and the process of freezing food involves the freezing point of water. As temperature of the surrounding air goes below the freezing point of water, the water progressively crystallizes out in the form of pure ice. Size of the crystals which form is determined by the span of time during which freezing takes place. When the temperature is lowered slowly, the crystals expand considerably. If the freezing is sharp and sudden, the crystals retain approximately the same size as the original water molecules.

In case you have doubts about how well a food will freeze, test it before freezing large quantities. To test, freeze three or four packages and sample the food a couple of weeks later. This will show the effect of freezing but not the effect of storage. Some varieties of the same kind of food freeze well, others do not.

Much of the success you have with your home freezer will depend on how you prepare, package, wrap and seal foods. Protecting frozen food is as important as freezing food of high quality.

You will need general kitchen utensils plus a steel, aluminum or enamel kettle large enough to hold at least one gallon of boiling water, with a tight fitting cover. Use a mesh basket, a strainer, or large squares of cheesecloth to hold one pound of vegetables in the boiling water.

Steaming of cut, sliced or green leafy vegetables is recommended and will preserve more nutrients than water does.

You will need a container to hold ice water for quick chilling of vegetables to stop cooking action. Drain thoroughly in a colander and turn out on absorbent towels.

It is false economy to skimp on wrappings and containers. They should protect the food from cold air, which is dry, so as to retain the moisture in foods and prevent freeze burn and dehydration. Select them according to the use they will be put to.

Most freezer containers on the market today are easy to seal, waterproof, and give satisfactory results. Rigid plastic containers, bags, and jars with wide tops are favorites.

Moisture- and vapor-resistant wraps, which are exceptionally effective at excluding oxygen, include heavyweight aluminum foil, coated and laminated papers, polyethylene films, saran, and polyester films. They should be strong and pliable so the wrap will adhere readily to irregularly shaped objects, and eliminate as much air as possible to avoid frost accumulation inside. Careful wrapping is of no avail if the package breaks. It should be easily sealed, either by heatsealing or freezer tape.

Freezer bags are available, and freeze-and-cook bags that withstand temperatures from below 0° F. to above the boiling point. The freeze-and-cook bags are suitable for freezing and reheating food. Points to consider include the size convenient for your use and the cost.

Materials not moisture-proof and vapor-proof, and thus not suitable for packaging foods to be frozen, are ordinary waxed papers, cartons from ice cream or milk, and plastic cartons from cottage cheese or gelatin products because they crack easily.

Compare price, durability, shape and reusability in selecting containers, keeping in mind their convenience and the economical use of freezer space.

Retaining the vitamins and other nutrients depends on how fruits and vegetables are handled before freezing, on storage temperature in the freezer, and on how you cook them. Always follow up-to-date recommendations available from the U.S. Department of Agriculture or county Extension office.

Select foods of top quality. A freezer is not magic--it does not improve food. Its function is to preserve quality and food values and to prevent spoilage.

Choose vegetables and fruits suitable for freezing, and the best varieties for freezing. Because growing conditions and varieties vary greatly across the country, check with your county Extension office to find out which varieties are best for freezing.

Freeze fruits and vegetables when they are at their best for table use. If possible, freeze those that are ripened on the tree, vine or bush. Fruits should be ripe but firm.

Enzymatic changes continue after harvest, lowering quality and nutritive value. If stored at too warm temperatures, fruits can lose vitamin C, turn brown, lose flavor and color, and toughen.

Don't delay in harvesting vegetables since asparagus, corn, peas, snap beans, and lima beans all deteriorate rapidly in the garden after reaching their peak.

Observe cleanliness while you work, to avoid contaminating foods.

Prepare vegetables for freezing by blanching them in boiling water for recommended times. County Extension offices will have information on specific times for various foods.

Blanching vegetables is absolutely necessary to inactivate enzymes that cause undesirable changes in flavor and texture. This brief heat treatment reduces the number of micro-organisms on the food, enhances the green color in vegetables such as peas, broccoli and spinach, and displaces air trapped in the tissues.

Pack food in containers as solidly as possible to avoid air pockets, leaving the necessary head space for expansion. Press out as much air as possible, with your hands or by using a freezer pump. Then seal the plastic bags by twisting the open end, folding it over. Freezer rubber bands, twist-seals, or freezer tape are satisfactory for sealing bags.

Label packages clearly and carefully with name of product, date when frozen, number of servings or poundage, and any information that will help you. Special pens are made for marking frozen food products. Or you can use a wax pencil or crayon.

Speed is important in preparing food and getting it into the freezer, so as to maintain quality. Put only the amount of unfrozen foods into the freezer at one time that will sharp freeze within 24 hours.

Allow at least one inch between packages of unfrozen food in the freezer for circulation of cold air. Leave packages in freezing position for 24 hours before stacking them close together.

Uniform freezing temperature and keeping frozen products at 0° F or lower will maintain quality. Different foods have varying storage periods, so keep your frozen food inventory changing.

Use a freezer thermometer in your freezer. Check your freezer door and wall plug daily to avoid any catastrophe.

A freezer can pay wonderful dividends with considerable thought and planning by the homemaker.

Pressure Canners, Vital for Low-Acid Foods

_by Nadine Fortna Tope_[6]

Use of a pressure canner for preserving low-acid foods is not new. Pressure canners for home canning were first marketed in the early 1900's. In 1917, the U. S. Department of Agriculture announced that use of a pressure canner at 10 pounds pressure (240° F) was the only safe method for canning vegetables. Today's recommendations are essentially the same.

A temperature of 240° F or 10 pounds pressure at sea level is needed to kill spoilage organisms in a reasonable time, especially the spores of _Clostridium botulinum_. These spores, if not killed, can produce the most deadly toxin known to man.

The commercial canning industry stringently follows safe canning practices. Their safety record is excellent. _A Complete Course in Canning_ by Lopez (1975) says that since 1925 four deaths have been reported from the consumption of more than 800 billion cans of commercially processed foods. The record for home canning is much worse--450 deaths in a fraction of the number of cans. Unsafe practices were probably used in preserving the deadly home-canned food.

Methods like open kettle, oven, and boiling water bath canning for low-acid foods are not sufficient to kill _Clostridium botulinum_ spores. Educators talk to many people even today who still use unsafe practices because "that's the way my mother always did it", or because they are unfamiliar with pressure canners.

In this chapter, the need for safe pressure canning procedures will be discussed along with the rationale for using care in preparing low-acid foods for canning.

Acidity of a particular food is the most important factor in determining which canning method should be used--pressure or boiling water bath.

Acidity is measured and stated much the same way we express length or weight. Acidity (pH) refers to acid strength, not the amount of acid present.

For example, citric acid, an acid found in oranges, grapefruit, and other citrus fruits, is a weak acid compared to hydrochloric acid, a very strong acid. The measure used to express acid strength is pH. The pH scale runs from 1 to 14 with 7 as the neutral point. Substances with pH below 7 are called acidic, while those above 7 are called basic or alkaline foods. The lower the pH, the more acid the food.

Acidity or pH of a food affects the length of time it must be processed at a particular temperature to make it safe. The more acid the food (the lower the pH), the shorter the time required for processing.

Almost all foods are acid in nature. Hominy is an example of a food that is neutral or slightly alkaline.

Foods are further categorized as high acid or low acid because the _C. botulinum_ spore will not grow at pH levels of 4.6 or below. High acid foods (pH 4.6 or below) include tomatoes and all fruits except figs. (See chart).

Those with a pH above 4.6 are the low-acid foods. All vegetables except tomatoes and those that have been pickled or fermented are low-acid.

Safe processing times have been established at 240° F for low-acid home canned products, since at this temperature the processing times are reasonably short and texture of the resulting product remains good. The heat-resistant _C. botulinum_ spore has been known to survive many hours of boiling at 212°. Once food reaches 240°, the spore is killed when held for the recommended number of minutes.

Fruit and Vegetable Acidity

High acid foods
Lemon Juice
Cranberry Sauce
Gooseberries
Rhubarb, Dill Pickles
Blackberries
Applesauce, Strawberries
Peaches
Raspberries, Sauerkraut
Blueberries
Sweet Cherries, Apricot
Tomatoes
Low acid foods
Figs, Pimentos
Pumpkins
Cucumbers
Turnips, Cabbage, Squash
Parsnips, Beets, Green Beans
Sweet Potatoes
Spinach
Asparagus, Cauliflower
Carrots
Potatoes
Peas
Corn

Holding of produce to be canned for long periods in warm summer temperatures gives bacteria ample time to multiply into vast numbers, thus increasing the chances of spoilage.

For example, one cell can multiply into a billion cells in just 15 hours of holding under favorable conditions.

Salt and spices added to low-acid canned products in amounts recommended do not appreciably alter processing time. Salt may slightly lower the heat resistance of some micro-organisms but not enough to present a problem if omitted for dietary reasons.

Fats and oils, if added, may reduce the rate of destruction of bacterial spores. Spores of _C. botulinum_ have been known to survive beyond all reasonable expectation when heated in oil suspensions. Thus, adding oil or fat to a product being canned could be dangerous and is not recommended.

The type, consistency, and piece size of food and how it is packed in the jars are important factors which affect processing time. In preparing jars of food for the pressure canner, follow directions carefully. Do not use jars larger than the directions specify.

Determining the safe processing time for a food product involves two important steps.

First, the rate of heat penetration is measured by finding the spot in the jar that takes the longest time to heat. This is referred to as the "cold spot". Times will depend on the type of food (squash vs tomato juice) as well as how it is prepared (whole kernel vs cream style corn).

The second step is done in a laboratory. A known amount of some live bacterial spores is put into the "cold spot" of the jar of food. These jars are then heated and the amount of time needed to kill the spores is determined.

How Food Is Heated

Heat is a form of energy which flows from hot to cold substances. This flow occurs by convection, conduction, and radiation. In a pressure canner, convection and conduction are the primary methods of heat transfer.

Convection heating occurs in thin liquids and in gases like air and steam. As molecules are heated, they become lighter and rise to the top of the jar, displacing cooler ones toward the bottom. This movement is visible in water that is being heated in a clear glass container. Convection heating occurs best in liquids like fruit and vegetable juices or broths. These heat rapidly and thus have shorter processing times.

Small quantities of starch either added or leached from vegetables slows down the convection and increases processing time. For example, jars of liquid containing pieces of green beans or peas would heat more slowly than apple juice because the pieces would interfere with convection.

A tightly packed jar takes longer to heat than a loosely packed one which allows some convection heating. Thus it is important not to over-pack jars as this will decrease the rate of heat penetration.

Some types of food heat by a combination of conduction and convection. One example is a peach half in thin sirup. The sirup heats by convection while the peach heats by conduction. Another example is cream style corn. Initially, the liquid is thin and heats by convection. As the liquid thickens, it heats by conduction.

Conduction occurs when heat is transferred from one particle or substance to another right next to it. This is the slowest type of heat transfer. Foods that mat together, like spinach, or viscous material like mashed pumpkin, heat by conduction. The larger the pieces of food or the thicker the puree, the slower the heat penetration.

Pressure Canners

A pressure canner is a kettle made from a material, usually aluminum, that is strong enough to safely withstand the pressures used in home canning. The lid is built so it can be locked to the base of the canner. On one type, metal in the sealing edge is ground smooth so little or no leakage occurs between the lid and the base. Care should be taken to avoid damage to the sealing surfaces which could ruin the canner.

Other canners have a gasket made of a rubber-like substance that prevents leakage of steam. The gasket should be washed in hot suds, rinsed, and dried thoroughly after use.

All pressure canners include a safety plug or fuse. One type has a metal fuse that melts when the temperature is too high. If the canner is used properly the fuse should never need replacing. Another type of canner has a rubber-like safety plug. Care should be taken to replace the plug when the rubber gets hard. As the rubber hardens, it takes a greater pressure for it to blow out. Some older type canners have a petcock that serves as a vent and safety valve.

In canners that have a pressure gage, vents serve to exhaust air from the canner. The air is exhausted by venting for 10 minutes after steam starts escaping. All the air must be exhausted before the canner is sealed because the steam has much more heat energy. For example, air in a 212° F oven feels just warm while 212° steam from a teakettle will burn you.

Be sure to read and follow the instructions with your canner.

All canners should have some type of rack in the bottom. A rack keeps the jars from touching the bottom of the canner and breaking. It also aids in transferring the heat more evenly within the canner by permitting water and steam circulation.

There must be enough water in the canner to provide steam throughout processing. Two quarts of water is usually recommended, although this may vary depending on size of the canner and the quantity of jars.

Pressure canners have either a dial gage, a pressure control or a combination of these. The dial pressure gage indicates the pressure and corresponding sea level temperature. The control type canner has a precision weight that sits on the vent pipe and jiggles to regulate pressure. A third type is a combination gage and control.

The dial pressure gage measures steam pressure. The tube in the pressure canner gage operates like a New Year's Eve noisemaker, which is a flat paper tube rolled up. Blowing into the tube causes it to become more round and unroll.

The pressure gage works the same way except not as dramatically. The gage is made of a partially flattened metal tube. When pressure is applied, the tube becomes more round and straightens slightly. The needle [pointer] moves as the tube straightens. The gage is calibrated to indicate pressure. Pressure is controlled by adjusting burner heat to maintain the desired pressure. This type of gage should be checked yearly or after suspected damage, such as dropping, to be sure it functions properly.

A pressure control consists of a precision weight that rests on a specially designed vent pipe. It automatically maintains an even pressure and temperature inside the canner. Pressure builds inside the canner until the upward force (steam pressure times seat area) is greater than the downward force of the weight on the seat area. At this point, the control weight is lifted, releasing steam and reducing pressure, until the upward force equals the weight. The pressure inside again increases slightly, lifts the weight, and releases the pressure.

The repeated lifting and reseating or jiggling of the control weight indicates that the pressure is being controlled.

The burner is adjusted so the control jiggles at least several times a minute. Excessive jiggling will deplete the supply of water in the canner.

There are two types of pressure controls. One type is a single weight with 3 holes which fit on the vent pipe. The diameter at the base of the hole (seat area) is different for each of the 3 pressures--largest for 5 pounds pressure, and smallest for 15 pounds pressure.

The second type has 1 seat area and a 3-piece weight. For 5 pounds pressure, the small center weight is used. One additional ring or weight is added for 10 pounds pressure, and a second ring or weight is added for 15 pounds pressure.

With care, the pressure control remains accurate throughout the canner's lifetime. Be sure that seat areas where the weight and the vent pipe make contact are not damaged or excessively worn; this could affect the canner's performance.

The combination gage is not as common as the other two types. It has a sliding piston which pushes up on a spring. As pressure inside the canner increases, the piston is pushed up. Rings on the piston indicate pressure. If the heat is not regulated correctly, pressure builds up to beyond 15 pounds, at which point the weight is lifted to release the excess pressure. It will jiggle audibly, indicating to the user that the pressure is too high. This system serves as a gage as well as a safety device.

The combination gage should be kept clean and dry when not in use, to prevent corrosion. It also must be checked yearly to be sure the piston slides easily and indicates the correct pressure.

Effect of Altitude

Atmospheric pressure is like the thickness of frosting on a cake. Where it is thickest it weighs more per square inch than where it is thin. At sea level, where the atmosphere is the thickest, it is heavier than atop a mountain.

As altitude increases, atmospheric pressure or its weight per square inch decreases. Altitude affects the boiling point of water. Where altitude is least, at sea level, water boils at 212° F. As altitude increases the boiling point of water decreases.

The same is true in a pressure canner. Under 10 pounds pressure at sea level, water boils at 240° F. As altitude increases, the temperature in a pressure canner at 10 pounds of pressure is less than 240°. This difference is enough to affect the safety of canned products at altitudes above 2,000 feet.

Processing time for a particular vegetable is the time it takes to heat the coldest part of the jar to a temperature of 240° F, and maintain it long enough to kill any _C. botulinum_ spores present. At an altitude of 2,000 feet, it takes 11 pounds of gage pressure for water to boil at 240°. For each additional 2,000 feet increase in altitude, 1 pound of pressure should be added.

For pressure canners that have the pressure control, the 15 pounds pressure weight should be used at altitudes above 2,000 feet for canning low-acid food.

At the end of processing, pressure inside the jars as well as inside the canner is 10 pounds. The pressure inside the canner should be allowed to drop slowly. If pressure inside the canner is released too rapidly, pressure inside the jars will be great enough to force the contents, especially liquid, out of the jars. This may prevent a jar from sealing if a piece of food lodges on the top of the sealing rim. It may even break the jar.

Remove the lid from the canner as soon as the pressure drops. Jars should then be taken out and allowed to cool to room temperature quickly. A type of non-toxic spoilage called flat sour can occur if the jars are allowed to stand in the canner for long periods.

When using the steam-pressure canner, the pressure given is for altitudes less than 2,000 feet above sea level. If you live in an area with a higher altitude, it is necessary to make an adjustment in pressure. See the next chapter for details.

Home Canning of Fruits and Vegetables

_by Carole Davis_[7]

Canning in the home is increasing in popularity as a method of food preservation. Economic considerations are causing consumers to look for ways to stretch their food dollars. By having their own gardens and canning the harvested produce, they often can save money. Eating quality of home-canned products encourages some individuals to can. The activity of growing or obtaining produce and preserving it in the home sometimes gives people a sense of personal achievement and satisfaction.

In canning, food is preserved by applying heat to prepared food in containers so that micro-organisms that cause spoilage or food poisoning are destroyed and enzymes that cause undesirable quality changes in the flavor, color, and texture of food are inactivated. Preservation of food by canning also depends on sealing the food in sterile, airtight containers to prevent it from coming in contact with micro-organisms in the environment.

Canning is not a difficult technique, but it must be done properly to avoid spoilage and food poisoning, such as the often fatal botulism. It is extremely important that only tested reliable instructions are used, such as those found in U.S. Department of Agriculture publications. Based on scientific research, specific instructions have been developed for preparing, packing, and processing each food. Instructions should be followed exactly from beginning to end--without taking any shortcuts or altering any recipes.

Acidity of the food is the chief factor in influencing the time and temperatures necessary for processing. The more acid the products, the easier spoilage organisms are destroyed by heat. Acid foods--such as tomatoes, fruits, and pickled vegetables--can be safely processed at the temperature of boiling water in a boiling-water-bath canner. If spoilage organisms are not killed by adequate processing, they will continue to grow and could reduce the acid in the canned product, thus encouraging the growth of more dangerous organisms, such as _Clostridium botulinum_.

Low-acid foods--all vegetables, except for tomatoes--require a more severe heat treatment than acid foods to kill the organisms. The only safe way to can these foods is with a steam-pressure canner, one with a weighted or dial gage, to obtain temperatures above boiling. _Clostridium botulinum_ is extremely dangerous in these low-acid foods because if it is present, and the heat treatment has been insufficient, it can grow and produce a deadly toxin in the sealed containers.

Processing times are based on sea level conditions where water boils at 212° F or, when under 10 pounds of pressure, at 240°. As the altitude increases, the temperature at which water boils decreases. Therefore, at altitudes above sea level you need to make adjustments in canning instructions to insure that foods are adequately processed.

When using a boiling-water-bath canner you must add more time in processing, as given in the table.

At altitudes above sea level it takes more than 10 pounds of pressure for the temperature of boiling water to reach 240° F.

When using the steam-pressure canner, the pressure must be increased although the time remains the same as that recommended for sea level. At altitudes above 2,000 feet, process as follows:

Altitude Pounds of pressure

2,000 feet 11
4,000 feet 12
6,000 feet 13
8,000 feet 14
10,000 feet 15

Altitude Corrections for Boiling Water Bath

Increase processing time if the time
recommended is:
Altitude (feet) 20 minutes or less More than 20 minutes

1,000 1 minute 2 minutes
2,000 2 minutes 4 minutes
3,000 3 minutes 6 minutes
4,000 4 minutes 8 minutes
5,000 5 minutes 10 minutes
6,000 6 minutes 12 minutes
7,000 7 minutes 14 minutes
8,000 8 minutes 16 minutes
9,000 9 minutes 18 minutes
10,000 10 minutes 20 minutes

Equipment

Use jars made especially for home canning so the jars will be the right size for the processing time and temperature used, properly heat tempered, and resistant to mechanical shock. Always check jars before using to be sure they do not have nicks or cracks. Wash jars in hot, soapy water and rinse well.

It is important to use standard jar closures. They are designed to fit home canning jars correctly, and are made from suitable materials to provide a proper seal. One of the most popular types is the two-piece lid with a metal ring or band and a flat metal disk with a sealing compound. Flat metal disks can be used only once since they may not seal properly if reused. Metal bands may be used repeatedly if they are not rusted or dented.

Wash and rinse lids and bands. Metal lids with sealing compound may need boiling or holding in boiling water for a few minutes; follow the manufacturer's directions. Porcelain-lined zinc caps with rubber shoulder rings can also be used to seal jars. Rubber rings should be used only once.

Water-bath canners are readily available on the market. However, any large metal container may be used for a water-bath canner if it is deep enough so the water is well over the tops of the jars and has space to boil freely. Allow 2 to 4 inches above jar tops for brisk boiling. The container or canner must have a tight fitting cover and a rack to allow water to circulate under the jars.

The steam-pressure canner is made of heavy metal and has a cover which fastens to make the pan steam-tight. The cover is fitted with a safety valve, a petcock or vent, and a gage--either weighted or dial. All parts of the canner must be clean and in good working order. Check the gage before the canning season, and also during the season if canner is used often. The weighted ones need only be checked to determine if they are thoroughly clean. A dial gage can be tested for accuracy by a county Extension agent or an equipment manufacturer.

A pressure saucepan may be used for canning pint jars of food. However, 20 minutes must be added to the processing time recommended for a particular food canned with the pressure canner. This is because pressure saucepans heat and cool more rapidly than pressure canners do. Thus additional time is needed to compensate for the otherwise reduced exposure of the food to heat.

Selecting and Preparing

Home-canned foods will be no better than the raw products with which you begin. Fruits and vegetables should be of good quality with no bruises or soft spots. Be sure to choose fresh, firm, ripe fruits and young tender vegetables. Use them before they lose their freshness. Do not use overripe produce because some foods lose acidity as they mature, and the recommended processing time may not be adequate.

Wash all fruits and vegetables thoroughly, but gently, to remove dirt which contains bacteria. Wash small quantities at a time under running water or through several changes of water. Lift fruits and vegetables out of the water so the dirt will not resettle on the food. Do not let fruits or vegetables soak, as they may lose flavor and food value. Peel and cut or slice produce as indicated in instructions for each specific fruit or vegetable.

Fruits and vegetables may be packed raw into jars, or preheated and packed hot. Raw or cold pack means that raw, unheated food is placed in jars and covered with boiling hot sirup, juice, or water. When foods are hot packed they are heated in sirup, water or steam, or juice for a specified length of time and then packed hot into jars.

Most raw fruits and vegetables can be packed fairly tightly into containers because they cook down during processing. However, raw corn, lima beans, and peas should be packed loosely because they expand during processing.

Hot food should be packed fairly loosely. It should be at or near the boiling temperature when packed. There should be enough sirup, water, or juice to fill in around the solid food in the container and to cover the food. Food at the top of the container may darken if not covered with liquid.

Do not overpack containers as this may result in underprocessing. It is necessary to leave headspace between the lid and the top of the food or liquid in the jar because there will be some expansion of food during processing. The amount of headspace varies with the product, style of pack, and method of heat sterilization, so follow directions for each fruit or vegetable.

When using the flat metal lid with sealing compound, put the lid on a clean jar rim, with sealing compound next to the glass. Then screw the metal band down firmly. The lid will still have enough "give" to let steam escape during processing. Do not tighten the band further after removing the jar from the canner.

When using the porcelain-lined zinc cap, fit the wet rubber ring down on the jar shoulder. Fill the jar and wipe clean the rubber ring and jar rim. Screw the cap down firmly and turn back ¼ inch. When the jar is removed from the canner, tighten the cap to complete the seal.

Processing Fruits

Sugar or sugar-water sirup is often added to fruits to help them hold their shape, color, and flavor. Sugar can be added in the dry form to very juicy fruits.

To make sugar sirup--mix sugar with water or juice extracted from the fruit. Proportions for 3 types of sirup are as follows:

Type of Sirup Sugar (cups) Liquid (cups)

Thin 2 4
Medium 3 4
Heavy 4¾ 4

Heat sugar and water or juice together until sugar is dissolved.

Fruit may be canned without sweetening--in its own juice or in water--for special diets. Processing time is the same for unsweetened fruit as for sweetened because sugar is not needed to prevent spoilage.

Process fruits by the boiling-water-bath method. Work only with the quantity of food needed for one canner load at one time.

As each jar is filled, adjust the lid, and place the jar on the rack in the water-bath canner about one-half full of hot or boiling water for raw or hot pack, respectively. Be sure the water is 1 to 2 inches over the tops of the jars, and there is an additional 1- to 2-inch space to allow the water to boil freely.

Cover the canner and when the water comes to a rolling boil, start to count the processing time. Boil gently and steadily for the recommended time for the fruit you are canning. A definite length of time is recommended for processing each kind of fruit.

When the processing time is completed, immediately remove the jars from the canner with a pair of jar tongs. Adjust the jar lids if necessary. Cool the jars on a rack or folded towel away from drafts.

Processing Vegetables

A steam-pressure canner must be used for processing all vegetables except tomatoes and pickled vegetables. Work only with the quantity of vegetable needed for one canner load at a time. As each jar is filled, adjust the lid, and place the jar in the pressure canner containing 2 to 3 inches of hot or boiling water for raw or hot pack, respectively, to keep food hot.

The manufacturer's directions for general operation of the canner you are using should be followed. A few pointers on the use of any canner follow:

--Use 2 to 3 inches of boiling water in the bottom of the canner.

--Set filled containers on rack in canner.

--Fasten canner cover securely.

--Allow steam to escape from open petcock or weighted gage opening for at least 10 minutes to drive all air from canner. Then close petcock or put on weighted gage.

--When pressure reaches 10 pounds (240° F), start counting processing time. Keep pressure constant by regulating heat under the canner.

--When processing time is completed, remove the canner from heat immediately. Cool undisturbed at room temperature until the pressure registers zero. After a minute or two, slowly open the petcock or remove the weighted gage. Unfasten the cover and tilt the far side up so steam escapes away from you.

--Remove containers from canner with jar tongs.

--Adjust lids if necessary.

--Cool jars on a rack or folded towel away from drafts.

Day-After Check

Jars should be examined after they have cooled, but within 24 hours after processing, to be sure a seal has been obtained. To test a jar that has a flat metal lid, press the center of the lid; if the lid is down and will not move, it is sealed. Turn jars with porcelain-lined zinc caps partly over in your hands; if they do not leak, they are sealed.

When jars are thoroughly cooled, metal screw bands should be carefully removed. Wipe outside of jars clean, and label jars to show date and contents. Store in cool dry place. If you find a jar that did not seal, use food right away or re-can the food immediately; empty the jar, pack and process the food as if it were fresh.

Look for Spoilage

Check dates on jar labels to be sure you first use food that has the earliest processing date. Before opening any jar for use, look at it carefully for spoilage signs. If it leaks, has a bulging lid, spurts liquid when opened, or has an off-odor or mold, then do not use it. _Do not even taste it._ Destroy it out of the reach of children and pets.

Canned vegetables may contain the toxin that causes botulism without showing any visible signs of spoilage. Therefore, boil all home-canned vegetables covered for at least 10 minutes before tasting or serving. Heating generally makes any odor of spoilage more evident.

If the food appears to be spoiled, foams, or has an off-odor during heating, destroy it.

How to Can Cut Green Beans[8]

1. Select green beans:
Choose young, tender beans
Allow 1½ to 2½ pounds of fresh beans for each quart to be canned
2. Prepare green beans:
Wash beans
Trim ends
Cut into 1-inch pieces
3. Pack into jars:
To pack raw--
Pack raw beans tightly into jar
Leave ½-inch space at top of jar
Add ½ teaspoon salt to pints; 1 teaspoon to quarts
Cover with boiling water to ½ inch from top of jar
Wipe jar rim clean
Adjust jar lid
Process in pressure canner at 10 pounds pressure (240° F)
Pints--20 minutes
Quarts--25 minutes
(At altitudes above sea level, increase pressure according to
instructions in early part of chapter)
To pack hot--
Cover cut beans with boiling water; boil 5 minutes
Pack hot beans loosely into jar to ½ inch of top
Leave ½-inch space at top of jar
Add ½ teaspoon salt to pints; 1 teaspoon to quarts
Cover with boiling water to ½ inch from top of jar
Wipe jar rim clean
Adjust jar lid
Process in pressure canner at 10 pounds pressure (240° F)
Pints--20 minutes
Quarts--25 minutes
(At altitudes above sea level, increase pressure according to
instructions given earlier)
4. Allow pressure to return to 0
5. Remove jars from canner
6. Complete seals, if necessary

How to Can Peaches[9]

1. Select peaches:
Choose fresh, firm, ripe fruit, with no soft spots or bruises
Allow 2 to 3 pounds of fresh peaches for each quart to be canned
2. Prepare peaches:
Wash peaches
Dip in boiling water; then in cold water
Slip off skins
Cut in halves and remove pits. Slice if desired
3. Prevent darkening:
Drop peeled peaches into solution of 2 tablespoons each of salt
and vinegar per gallon of water
Drain just before heating or packing raw
4. Pack into jars:
To pack raw--
Pack raw peaches in jar to ½ inch of top
Cover with boiling sirup (See sirup table)
Leave ½-inch space at top of jar
Wipe jar rim clean
Adjust jar lid
Process in boiling-water bath--
Pints--25 minutes
Quarts--30 minutes
(At altitudes above sea level, increase processing time according
to table near start of chapter)
To pack hot--
Heat peaches through in hot sirup (See sirup table). If fruit is
very juicy, heat it with sugar, adding no liquid
Pack hot fruit in jar to ½ inch of top
Cover with boiling sirup
Leave ½-inch space at top of jar
Wipe jar rim clean
Adjust jar lid
Process in boiling-water bath--
Pints--20 minutes
Quarts--25 minutes
(At altitudes above sea level, increase processing time according
to table near start of chapter)
5. Remove jars from canner
6. Complete seals, if necessary

Freezing Your Garden's Harvest

_by Annetta Cook_[10]

The growing season brings an abundance of fruits and vegetables freshly harvested from your garden. The unmatchable sweetness of peas cooked fresh from the pods, the tender-crisp texture of fresh broccoli, the delectable flavor of sweet juicy strawberries are irresistible. It is always a disappointment when the growing season is over. You may have more produce than you were able to use within a short time, so why not savor its just-picked freshness during the autumn and winter months--freeze it!

Of all the methods of home food preservation, freezing is one of the simplest and least time-consuming. The natural colors, fresh flavors, and nutritive value of most fruits and vegetables are maintained well by freezing. However, to freeze foods successfully--that is, to preserve their quality--produce must be carefully selected, prepared and packaged, and properly frozen. Be sure to use reliable home-freezing directions such as those found in U.S. Department of Agriculture publications. Unless recommended practices and procedures are observed, the food's eating quality will be a disappointment.

The first consideration before deciding whether to freeze the garden's harvest is whether your freezer can maintain temperatures low enough to preserve quality of the food during freezer storage. Storage temperatures must be 0° F (-18° C) or below to help prevent unfavorable changes in the food, including growth of bacteria. The temperature control of your freezer should be adjusted so the warmest spot in the freezer will always be at 0° F or lower. Freezers and most two-door refrigerator-freezer combinations are best suited for long storage of home-frozen fruits and vegetables since they can be set to maintain this temperature.

Proper preparation of produce is also important to insure high eating quality of frozen vegetables and fruits. Vegetables, except green peppers and mature onions, maintain better quality during freezer storage if blanched, or heated briefly, before freezing.

Blanching is necessary to prevent development of off-flavors, discoloration, and toughness in frozen vegetables. Besides stopping or slowing down the action of enzymes responsible for these undesirable changes, blanching also softens the vegetable, making it easier to pack into containers for freezing.

Fruit does not need to be blanched before freezing. However, most fruits require packing in sugar or sirup to prevent undesirable flavor and texture changes in the frozen product. Sugar, either alone or as part of the sirup, plus the acidity of fruit retards enzyme activity in fruit stored at 0° F or below.

Packaging Material

Material selected for packaging fruits and vegetables for freezing must be moisture-vapor-proof or moisture-vapor-resistant to keep the food from drying out and from absorbing odors from other foods in the freezer. Loss of moisture from the food causes small white areas called "freezer burn" to develop. These areas are not harmful, but if extensive they can cause the food to become tough and lose flavor.

Suitable packaging materials include rigid plastic food containers, plastic freezer bags, heavy aluminum foil, freezer paper or plastic film, glass freezer jars, and waxed freezer cartons. Collapsible, cardboard freezer boxes are frequently used as an outer covering for plastic bags to protect them against tearing.

Select packaging materials suiting the shape, size, and consistency of the food. Rigid containers are suited for freezing all foods, but are especially good for fruit packed in liquid. Non-rigid containers are best for fruits and vegetables packed without liquid. Paper, plastic, or foil wraps are ideal for freezing bulky vegetables such as broccoli, corn on the cob, and asparagus.

Rigid containers with straight sides and flat bottoms and tops stack well in the freezer. They take up less freezer space than rounded containers, containers with flared sides, and bulky, wrapped packages or plastic bags without protective outer cartons. Containers with straight sides or those that are flared, having wider tops than bottoms, are preferred for easy removal of the food before thawing. If the opening is narrower than the body of the container, the food will have to be partially thawed so you can get it out of the container.

Freezer containers and bags are available in a variety of sizes. Do not use those with more than ½-gallon capacity for freezing fruits and vegetables since the food will freeze too slowly, causing poor quality food.

Choose a container that will hold enough food for one meal for your family. You may wish to put up a few smaller packages for use when some family members are not home or to go with your family-size packages when guests are present for meals.