Root Crops

Some fruits and vegetables can be stored outdoors in a partially buried galvanized garbage can or wooden barrel.

Root crops such as beets, carrots, celeriac, kohlrabi, rutabagas, turnips, and winter radishes should not be put in storage until late fall. Root crops keep best between 32° and 40° F. They require high humidity to prevent shriveling. Continued storage at 45° causes them to sprout new tops and become woody.

Large and overmature root crops may become tough and stringy in storage. Small and immature root crops probably will shrivel.

Dig root crops when the soil is dry and the temperature consistently low. Prepare them immediately for storage. Cut the plant tops about a half inch above the crown. Beets will bleed unless 2 to 3 inches of the top is left. You may wash the roots if you let them dry again before storing. Do not expose them to drying winds, and be sure they are cool when put in storage.

Prevent bitterness in carrots by storing them away from fruits such as apples, which give off volatile gases while ripening.

Turnips and rutabagas give off odors, so don’t store them in your basement. Find a separate spot, or store them with other root crops and vegetables in an outdoor cellar or pit.Turnips may be left in the garden longer than most other crops. They withstand hard frosts, but are damaged by alternate freezing and thawing. All other root crops can be stored together in your basement storage room.

VEGETABLE-FRUIT STORAGE GUIDE

Root crops keep their crispness longer when bedded in layers of moist sand, peat, or sphagnum moss. However, perforated polyethylene bags and box liners are easier to use than bedding. Root crops can be stored in crates or boxes in moist air, but they gradually lose moisture and quality unless polyethylene liners are used. Carrots and beets may be stored in 10-gallon crocks or any container that will prevent excessive shriveling.

Quick dipping of dried and trimmed turnips, rutabagas, or parsnips in wax will prevent shriveling. Float a layer of jelly-type paraffin on top of a kettleful of heated water which is deep enough to cover the vegetable. Dip room temperature vegetables quickly through the layer of wax.

For a thinner, harder wax film add a little salt and 10 to 20 percent clean beeswax.

Potatoes are the principal root crops you will probably store. Potatoes are eaten from the time they are of sufficient size for early use until storage time, and during storage when the vines have fully ripened.

If potatoes are harvested before maturity the skin may flake off easily. They are all right for immediate use, but not for storage. Immature potatoes shrink badly, bruise easily, and will not keep well very long.

For storage, potatoes should be allowed to mature and develop a thick skin. When the tops lie down the tubers should be mature enough for storage.

Dig potatoes carefully to avoid bruises, for better storage life.

Handle newly dug potatoes with care until the surface has dried or cured a few hours or more. You can keep them in baskets or slatted crates in single layers at first.

Store sound mature tubers in darkness at a minimum relative humidity of 95 percent and 45° to 48° F for highest quality. For very long storage keep at a temperature of 38° to 40° to prevent sprouting. The starch changes to sugar if potatoes are held below 45°. Potatoes may not show any external effect from exposure to these lower temperatures, but sometimes darkened tissue will be seen if the potato is cut and exposed to air.

Light causes considerable “greening” in potatoes. The green portion contains an undesirable substance that gives a bitter flavor.

Sweet potatoes that are well matured, carefully handled, properly cured, and stored at 55° to 60° F can be kept until April or May.

Sweet potatoes are easily bruised and cut. Handle them carefully and as little as possible. Put them directly in storage containers at harvest.

Cure freshly dug sweet potatoes by holding them about 10 days under moist conditions at 80° to 85° F. In the absence of better facilities, sweet potatoes can be cured near your furnace. To maintain high humidity during curing, stack storage crates and cover them with paper or heavy cloth. If the temperature near your furnace is between 65° and 75°, the curing period should last 2 to 3 weeks. After curing, move the crates to a cooler part of your basement or house where a temperature of about 55° to 60° can be maintained.

In houses without central heating, sweet potatoes can be kept behind a cookstove or around a warm chimney. If you keep sweet potatoes this way, wrap them in fireproof paper (to slow down temperature changes) and store them in boxes or barrels.

Sweet potatoes are subject to damage by chilling. Do not store them at 50° F or below.

Outdoor pits are not recommended for storing sweet potatoes, because dampness of the pits encourages decay.

Even though the home canner has canned plenty of tomatoes, it may be desirable to keep some of the fresh fruit. Keep tomatoes in the garden as long as possible. You can protect against early fall frosts by covering the plants with burlap or old carpets in the evening when frost is predicted. Polyethylene may also be used but injury will occur wherever it touches the plant.

In the summer, tomatoes should be harvested when fully vine-ripened for best quality. Pick when the color is a dark red in red varieties. During fall when frost is likely, mature green fruit can be picked and it will develop a red color when kept in a fairly warm place. The fruit is in the “mature-green” state if the tissues are gelatinous or sticky when the tomato is cut and the tomato interior is yellowish. Immature green tomatoes don’t ripen satisfactorily.

To check your judgment, cut a tomato in half that you feel is mature green. If the pulp that fills the compartments is jelly-like, it is mature green. The seeds are dragged aside easily by the knife and not cut through. In immature green tomatoes, seeds are easily cut through and the jelly-like pulp has not yet developed. Usually you can recognize the mature green ones by their glossiness, less hairiness, and more whitish green color.

You can pick mature-green fruits and bury them in deep straw or place in a room where the temperature is 60° to 70° F. The tomatoes will ripen over a period of 3 or 4 weeks. Sunlight is not needed to ripen green-ripe tomatoes, so don’t bother to put them on window sills. They ripen satisfactorily in the dark. Generally, tomatoes store best at 55° to 60° and ripen at 70° or room temperature.

You can wash the mature green fruits in a weak solution of household bleach and then wrap in paper to store and ripen.

Some people pull up the vines just before frost and hang them in the basement or garage to ripen their fruit.

Harvest onions for storage when the neck of the plant dries down, the tops have fallen over, and the roots are dry and have stopped growing from the stem plate. At that time the outer scales of the bulb are drying out and do not cling tightly (outer scales of yellow-skinned varieties change to a darker color).

Pull the onions by hand and lay in a windrow to cure with the topsplaced over the bulbs to prevent sun-scald. Onions may also be cured in an open shed. Remove onions with thick neck (seeders) before storage and discard all diseased bulbs.

After curing, place onions in open-slatted crates or burlap bags for further field curing or drying. Then place in storage. You may use either common storage or refrigerated storage.

Low temperatures in storage reduce shrinkage due to moisture loss and stop disease development. Keep the humidity as low as possible. Good management of ventilation is important. Ventilate storage early in the morning.

Onions held in cold storage should be placed there immediately after curing. A temperature of 32° F is ideal and will keep onions dormant and relatively free of rot. If sprouts grow it indicates too high a temperature, poor curing, or immature bulbs. If you have root growth the humidity is too high. The humidity should be 65 to 70 percent.

Do not store onions with produce that is likely to absorb the odor. Onions stand slight freezing, but do not handle or move them until they thaw. You can store onions in a dry, well ventilated attic or unheated room. Maintain as near 32° F as you can and keep as dry as possible. You can hang open-mesh bags, about half full, from overhead hooks or nails. Slatted half full crates of onions may be stacked on cross bars.

Chemical changes take place in the ripening process of apples and pears. This activity is called respiration. Starch changes to sugar, acids and insoluble pectins decrease, and volatile gases are given off. This continues until the fruit becomes overripe and mealy. During this ripening process oxygen is consumed from the air, and water and carbon dioxide are produced and heat is generated.

You may slow respiration by cooling fruit as rapidly as possible after picking. The sooner this is done the longer the fruit will keep.

Research indicates that when apples are stored at 30° F, about 25 percent more time is required for them to ripen than at 32°. Stored at 40°, the rate of ripening is about double that at 32°. At 60° the rate is close to three times that at 40°, and at 85° the softening and respiration rates have been found to be about double those at 60°. This emphasizes the importance of cooling quickly and keeping cold. The average freezing point of apples is about 28° or 29°.

Most apple varieties keep best at a temperature of 30° to 32° F and a relative humidity of 85 to 88 percent. However, McIntosh, Yellow Newton, and Rhode Island Greening apples do best at 35° to 38°. This prevents internal browning and brown core.

Pears can be stored ideally at 30° to 31° F. The highest freezing point for pears is about 29°. Since pears are likely to shrivel, keep the humidity at 90 percent. Most pears won’t ripen satisfactorily for eating at the above temperatures. They should be taken out of storage and ripened between 65° and 70°. This is ideal for Bartletts.

Bartlett pears ripen faster than apples. If you store pears too long they will not ripen properly. Don’t store Bartletts after 3 months or Anjou longer than 6 months.

Maintaining desired temperatures for home storage of apples and pears may be difficult. If you must settle for 40° F or even higher, you won’t get the good results you would if you refrigerate at the optimum temperatures. Sometimes cold storage facilities are available where you may store your fruit for a set price per container.

Don’t mix windfalls (fruits that have dropped to the ground) withfruit you pick from the tree. Windfalls are overripe and give off ethylene gas which speeds ripening of picked fruit.

Desirable temperatures may be possible in refrigerator hydrator drawers for small quantities.

An extra refrigerator can be used to store fruit, but do not take the shelves out. When it is empty, for safety reasons take off the doors.

Storing fresh cherries, peaches, and apricots very long is difficult. Refrigerate as close to 32° F as possible. Peaches ripen well at 65° to 85° and refrigerate well in hydrators for as long as 4 weeks. Peaches may be stored in walk-in refrigerators in larger quantities.

Grapes are generally not adapted to long storage. Concord grapes may be stored 4 to 6 weeks at 31° to 32° F. Catawba and Delaware varieties can be held 8 weeks. Vinifera table grapes such as Emperor and Ribier will keep 3 to 6 months at 30° to 31°.

Since apples, pears, grapes, and other fruit absorb odors from potatoes,onions, and other vegetables, store them separately.

Some kitchen garden herbs, such as chives and parsley, may be potted and cared for as house plants. These plants will supply flavoring and garnishing to enhance wintertime meals.

Trying to predict exactly how long your fruits and vegetables can be stored is next to impossible. Much depends on condition of the product and how successful you are in maintaining correct temperatures and humidity. Generally, you can keep parsnips and carrots all winter, late potatoes 6 to 8 months, cabbage 3 months, onions 6 to 10 months, and pumpkins, squash, root crops, and tomatoes 3 to 6 months.

Cleanliness.One last precaution: Keep the storage areas clean and free of decaying fruit and vegetables; otherwise, molds and bacteria will spread to your sound produce.

If you store nuts (especially peanuts), soybeans, other dry beans or peas, make every effort to prevent growth of molds. Moisture, temperature, and time are necessary to promote their growth. A harmful toxin may be produced if mold growth is allowed to progress. It is important that storage areas be regularly checked so as to avoid this type of contamination.

Discard all produce that shows any sign of decay.

Insects, rats, and other pests can spread disease and are unwanted guests in any food storage area. To escape these undesirables:

—Build them out. Close all cracks and use adequate screening over all openings—Prevent trash piles from accumulating—Keep the storage area clean—Control rats inside and outside. (Seek the advice of your county Extension office or a sanitarian)—Destroy any infested food—Remove all containers at least once a year. Wash them and air dry in the sun—Remember that good housekeeping practices apply to all places where food is stored

—Build them out. Close all cracks and use adequate screening over all openings

—Prevent trash piles from accumulating

—Keep the storage area clean

—Control rats inside and outside. (Seek the advice of your county Extension office or a sanitarian)

—Destroy any infested food

—Remove all containers at least once a year. Wash them and air dry in the sun

—Remember that good housekeeping practices apply to all places where food is stored

U.S. Department of Agriculture,Storing Vegetables and Fruits in Basements, Cellars, Outbuildings, and Pits, H&G Bul. No. 119, on sale by Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402. 40¢.

by F. Aline Coffey and Roger Sternberg[19]

A community cannery is a self-help facility equipped for preparing and heat processing food. People bring in produce from their gardens and through their own efforts preserve it for future use.

Community canneries began during the late 1800’s in response to the desire of families to work together to preserve their food for the off-season. At the end of World War II there were over 3,800 community canneries in the United States. Most of these wartime canneries were subsidized, but after the war the monies ceased. Growth of the food industry, development of freezing techniques, and the lack of subsidy led to a decline of the canneries.

Today there is a resurgence of interest in establishing community canning centers. This has been influenced by the cost of food, a marked increase in the concern for nutrition, and gardening activities.

A community cannery promotes the preservation of seasonal garden surpluses for consumption during the nonproductive season. It encourages small farmers and nonfarm individuals to produce more food, thereby promoting self-sufficiency for families. It enables families who do not own recommended food preservation equipment to use safe and reliable equipment and techniques.

Availability of nonseasonal foods on a year-round basis can result in a better diet for families, especially if the center incorporates nutrition education classes as part of its program. People who grow their own food may make substantial savings in their food budget. The community cannery creates a social atmosphere of friendly, cooperative work leading to tangible results, and promotes a feeling of self-reliance.

Most of the community canneries in the country have been organized by Community Action Agencies or similar community organizing groups. Individuals, food co-ops, and other groups have successfully set up canneries, but it is recommended that people wanting to establish a canning center contact a community organizing agency. Normally, these agencies have professional people who will work on such a project. They have experience in writing proposals and are aware of potential funding sources.

Support for the canning center can be enhanced by making a special effort to include a diverse membership on a board of directors for the center.

Farmers, low-income people, business people, contractors, Extension personnel, community organizers, local officials, and members of the clergy are all potential supporters and advisors for the cannery.

Although organizing a community cannery requires a lot of work, this need not be a roadblock to initiating the project. It takes many hours to plan the canning operation, draft proposals, develop community support, locate a site, and to select, purchase and install equipment. Because this can easily be a full-time job for one person, efforts should be made to hire a coordinator. In many instances, paid community organizers, Vista volunteers, and home economists have provided valuable assistance in completing the work.

Preparation for and organization ofthe cannery are the foundation of the project. At least six months should be set aside for organizing.

William E. CarnahanTomatoes in the canning process, at a community cannery.

William E. CarnahanSweet corn ready to have kernels removed for canning.

At later stage, liquid is poured over hot-packed corn. Note one advantage of a community cannery is that quantities of food can be processed in a few hours.

Here are some questions to consider before starting a community center:

How many people will commit themselves to organizing a center?

How much time will they give?

How much support can be expected from the community, town officials, local growers?

How many community and family gardens are in the area?

How near are the community gardens to the cannery site?

Is the site near a well-travelled route?

Is parking available?

Can the canning center exist merely to provide a service to the community, or will the cannery have to become involved in a commercial venture?

If some food processed at the cannery is to be sold, are local farmers willing to contract with the cannery to supply it with produce? How close are these farmers to the cannery?

Is a building available for canning purposes (for example, some old creamery)?

If so, what is the size of the building? What is its condition?

Are there cement floors and walls constructed so they can be washed down daily?

Is there room for storage, a walk-in cooler?

Is the sewage system adequate?

Does the building have existing equipment that could be put to use?

Is a dependable supply of potable water available?

What is the minimum water pressure and is it constant?

Is the water “hard?” If so, what is the analysis?

What type of electricity is available?

What is the cost of electricity per KWH and demand rate for 240 volt, 3 phase, 60 cycle?

What is the availability and cost of gas (natural or LP) or of fuel oil?

What is the number of families expected to participate? How many are low-income families?

What are the principal foods to be canned?

If it is anticipated that some products will be processed for sale, what will those products be?

Is there a market for the “for-sale” items?

Will canning supplies such as jars, lids, screw bands, tin cans be available? Can they be purchased at wholesale prices?

Is at least one person who is knowledgeable in food preservation methods available to supervise the cannery?

What will be the charge for processing a pint or a quart of food?

Will low-income people be able to pay this amount?

Are funds available to subsidize the canning of food for low-income people?

It is important to obtain a site easily accessible to the public. Selectmen, property owners, realtors should be approached for potential sites. Usually the center has limited funds, and it is difficult and takes time to locate an appropriate building with low-cost rent.

In times of a strained economy and high cost of property maintenance, the business community may be hesitant to provide low-cost housing for the site.

Establishing the facility in a publicly owned building, such as a school, is a solution in many communities. These canneries are a part of the public school’s physical plant and have traditionally been operated under supervision of the vocational agriculture and home economics teachers, using school funds.

In recent years, some schools have wanted to close canneries for several reasons: Lack of operating capital, limited use, lack of interest or know-how on the part of participants and teachers. With the resurgence of interest in canning, many new cannery ventures are located in schools but are now funded separately from school budgets.

If the cannery is the result of a community endeavor, adjoining small towns could appropriate funds sufficient to set up and man a center. Such a proposal would have to be presented to the town governing bodies. This points up the need for ample planning time. Devising means to allow the cannery to remain open year-round would favor obtaining a site other than in a public building.

Cost of organizing a community cannery is influenced by its size and scope of operation. Expenses can be broken down into these major areas:

At least two companies manufacturecommunity canning equipment (Ball Corp. and Dixie Canner Equipment Co.). Prices start at $4,300 for a single-unit operation, and go up to $20,000 for a large center. This does not include the price of a steam boiler, which costs between $3,000 and $5,000. By fabricating some of its own equipment, and by buying used equipment from canning and restaurant equipment suppliers, the cannery can reduce some of its purchase costs substantially.

Installation of the canning equipment and the steam boiler needs to be done by a licensed plumber or steam fitter, or be closely supervised by such a person.

Renovation of a building and installation of the canning equipment can cost between $4,000 and $8,000, including labor costs. Cost can be reduced by soliciting volunteer labor from local craftsmen. The organizers can handle much of the renovation, such as painting, carpentry and cement work. Teams of vocational students may be willing to take on the site renovations as part of their school training.

Salaries for employees can be paid from the cannery’s operating budget. Labor costs can be reduced if the workers are already salaried employees provided by other food-related agencies. The cannery can also be an ideal training site for participants in the Comprehensive Employment and Training Act (CETA) and can be staffed successfully in this way.

Food and Drug Administration regulations regarding food processing do not apply to community canning centers if they are not involved in interstate commerce. In June, 1976, FDA issued “Suggested Minimum Guidelines for Community Canning Operations” to protect the safety of the consumer.

Environmental regulations that apply to the centers must be carefully followed. Although these regulations are usually not hard to follow, they often mean a possibly unplanned-for expense to the cannery. It may be necessary to apply for a variance to zoning regulations. Cannery supervisory boards should have a working knowledge of all requirements of State and Federal agencies that regulate health, environment, fire, safety, plumbing, electricity, and public building codes.

Sites for the centers should have sewage and draining systems that meet demands of the centers. This would mean a septic system and leach fields, or a municipal sewage system, the latter being the easiest and least expensive method of disposal. Solid waste produced by the center is termed “clean,” and effluent from the processing could be put through a strainer, piped out of the center, and then deposited into a leach field.

To maintain high standards of cleanliness and safety, at least one supervisor should be on duty whenever the cannery is in operation. The person in charge must have a thorough knowledge of every aspect of food processing.

The Food and Drug Administration requires that a “certified registered canner” be in attendance only when low-acid foods are processed to be sold. An FDA-approved course is offered by the National Canners Association for commercial cannery personnel in various sections of the country. The cost would involve a registration fee of approximately $125 plus expenses. At present, the course content is geared chiefly toward industry. A shift to a more practical approach would be of greater help to community cannery personnel.

Cannery supervisors and attendants can participate in food preservation classes and demonstrations provided by the Extension Service. When canneriesare equipped with commercial food preservation centers, representatives of the manufacturing companies are available for technical information to the cannery staff. Manufacturers may also provide the cannery with a complete operations manual, processing charts, and recipes.

Cannery supervisors will benefit by employing people to work at the cannery who can provide or learn such skills as:

Bookkeeping/accounting—to keep records of input and outflow of goods and money; to pay bills.

Management—to oversee the flow of food through the center in an efficient manner for smooth operation of the plant.

Maintenance and repair—to maintain equipment and housing in operational condition.

Purchasing/supply—to ensure a supply of materials such as jars and lids.

Sales—to manage sales of surplus retail products if these are processed at the plant.

Public relations—to advertise and promote knowledge of canning centers; to handle complaints and problems of patrons.

Technical—to provide detailed information on processing techniques, food, nutrition, and gardening.

A form of recordkeeping on all foods processed at the plant is essential. This kind of information would include such data as name of person doing the processing, the date, specific food, number of jars, method of processing, time in and time out, and an identification number for foods processed for sale by the cannery.

Canning centers may be incorporated as independent nonprofit cooperatives with a board of directors as the policymaking body. By being organized in conformity with the traditional farmers’ cooperative structure, the centers receive special tax considerations. Incorporation on a nonprofit basis is a requirement of many funding sources. The cooperative structure also lends itself to a tighter knit organization, with members feeling they are part of the organization, responsible for its affairs, and willing to pitch in and help if there is some work that needs a few extra hands.

The community cannery should have general liability insurance to cover injuries sustained by the workers or persons using the canning center. Products liability insurance is unnecessary for the cannery operated solely to provide a service to the community. For the cannery that sells commercially, products liability insurance should be obtained.

Sealer in a community cannery.

A community cannery should be available to all people interested in preserving food. Ideally, canneries are open during daytime and evening hours. Weekend hours are a possibility. When canneries are limited to processing vegetables and fruits, atleast 6 months of potential operation are lost in certain sections of the country. If at all possible, canneries should be operated to process a wider range of foods such as jams, jellies, pickles, preserves, meat, fish, poultry.

William E. CarnahanTomato juice being processed at a community cannery. Since cannery is operated by State of Virginia, only charge is for cans used.

A processing fee is usually set for use of the canning equipment, ranging from 5¢ to 10¢ for pints to 10¢ to 15¢ for quarts. These prices do not include the cost of jar, lid, screw band, or any canning supplies such as salt, vinegar, sugar, spices that may be sold at wholesale prices at the cannery. An additional charge of 50¢ per hour is common for the use of a pulper-juicer and steam-jacketed kettle.

It may be a financial hardship for some low-income families to meet these costs, but they can be given the opportunity to exchange work time at the cannery for payment. Families of limited resources might leave off a percentage of their processed high-acid foods to be sold by the cannery. Sponsoring agencies may apply for grants, such as might be available from Title XX of the Social Security Act, in an effort to subsidize canning costs for low-income families.

To date, no community canneries are completely economically self-sufficient, so far as we know. There are centers in the South which do enough community canning to pay for all their expenses except salaries. To become self-supportive, some canneries are now developing specialty products to be sold commercially. Organic-health food distributorships and food co-ops are often a good market for community cannery processed foods.

The future of community canneries depends on continued interest in home gardening and food preservation, and concern for proper nutrition. Undoubtedly, the cost of food in the marketplace will also be a contributing factor.

by Carole Davis and Annetta Cook[20]

Consumers frequently have questions regarding home food preservation practices. Below are some questions commonly asked, and the answers. They concern canning fruits, vegetables, pickles, and jellies, and freezing fruits and vegetables.

Why is open-kettle canning not recommended?

In open-kettle canning, food is cooked in an ordinary kettle, then packed into hot jars and sealed. The food is not processed after packing in the jars.

Open-kettle canning is unsafe because temperatures reached are not high enough to destroy all the spoilage organisms that may be in low-acid foods, such as meat and vegetables, other than tomatoes.

Spoilage bacteria may also enter the food when it is transferred from kettle to jar, making it undesirable as well to can other foods such as fruits, pickles, preserves, and jams by this method.

Why is oven canning unsafe?

Jars may explode, causing personal injury or damage to the oven. Also, temperatures obtained in the oven are not high enough to insure adequate destruction of spoilage organisms in low-acid foods.

Times specified for boiling-water-bath processing of foods do not apply to oven processing since the rate of heat penetration would be different in the oven and the products could easily be underprocessed.

Should jars and lids be sterilized before canning?

No, not when the boiling-water-bath or pressure-canner method is used, because the containers and lids are sterilized during processing. But be sure jars and lids are clean.

Why is no liquid added when tomatoes are canned?

Because tomatoes provide their own juice if pressed gently when packed raw, or when heated before packing hot into jars.

Is it safe to add celery, green pepper, and onion to tomatoes when canning them?

No. Adding other vegetables lowers the acidity of tomatoes. Acidity helps protect against the growth of botulinum bacteria, which can produce a fatal toxin in canned foods. Specific recipes, times, and temperatures determined scientifically for vegetable mixtures need to be used for their safe canning.

Why is headspace important in canning?

Headspace—the distance between the surface of food and the underside of the lid—allows for expansion of solids or bubbling up of liquid during processing. If headspace is not adequate, some food in the container will be forced out, leaving food particles or sirup on the sealing surface and preventing a seal.

When too much headspace is allowed, some air may remain in the jar after processing, causing food at the top of the jar to darken.

What causes jars to break in a canner?

Breakage can occur for several reasons: (1) Using commercial food jars rather than jars manufactured for home canning, (2) Using jars that have hairline cracks, (3) Putting jars directly on bottom of canner insteadof on a rack, (4) Putting hot food in cold jars, or (5) Putting jars of raw or unheated food directly into boiling water in the canner, rather than into hot water (sudden change in temperature—too wide a margin between temperature of filled jars and water in canner before processing).

What causes liquid to be lost from jars during processing?

Loss of liquid may be due to packing jars too full. Headspace must be allowed between the top of the food and lid as specified in the instructions for each food. Food expands when processed, so headspace must be adequate or liquid will be forced out of the jar.

Liquid may be lost if the canner’s pressure fluctuates during processing. Lowering the pressure too suddenly after processing may also cause liquid to be lost. Pressure canner should be removed from the heat and allowed to cool normally at room temperature.

If liquid is lost from jars during processing, can more be added to fill them again?

No, because if the jar is opened and liquid added, this would allow bacteria to enter the jar and you would need to process again.

Loss of liquid does not cause food to spoil, though food not covered by the liquid may darken.

Why does fruit sometimes float in the jar after canning?

Fruit may float because it is packed too loosely, sirup is too heavy, or because some air remains in tissues of the fruit after heating and processing.

How do you test the seal on home-canned foods?

After jars have cooled, check two-piece lids by pressing the center of the flat metal lid; if lid is down and will not move, jar is sealed.

For porcelain-lined caps, check seal by turning each jar partly over in your hands. If no leakage occurs, the jar is sealed.

What causes lids not to seal?

If food has not been sufficiently heated, a vacuum may not be drawn on the jar of food and the lid will fail to seal. Presence of food particles or sirup on the jar rim could also prevent obtaining an airtight seal. Each jar rim should be wiped clean of all food and sirup before putting the sealing lid in place.

If food has been packed too tightly in the jars or if sufficient headspace has not been allowed, expansion of the food during heating could force sirup or food out of the jar, thus causing poor contact between the lid and jar.

Why should flat metal disks and rubber rings be used only once?

Depressions in the rubber compound made when the lid or ring was first used can prevent obtaining an airtight seal if used a second time.

Why should metal bands be removed after jars have cooled?

If bands are not removed soon after cooling, moisture between the ring and jar may cause the ring to rust, thus making later removal of the bands difficult. The band is no longer necessary after the jar has cooled because the seal has been provided by the flat metal lid with sealing compound and the vacuum created during cooling.

What causes canned foods to change color?

Darkening of food at the top of the jar may be caused by oxidation due to air in the jar, or by too little heating or processing so that enzymes are not destroyed. Overprocessing may cause discoloration of foods throughout the jar.

Pink and blue colors sometimes seen in canned pears, apples, and peaches are caused by chemical changes in the fruit coloring matter.

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