Causes and Possible Solutions for Problems with Canned Food

Problem Cause Prevention
Loss of liquid from glass jars during processing. Do not open to replace liquid. (Not a sign of spoilage) 1. Lowering pressure in canner suddenly, after processing period. 1. Do not force pressure down by placing canner in a draft, opening the vent too soon, running cold water over the canner, etc. Allow pressure to drop to zero naturally; wait 10 minutes before opening after weight is removed from canner lid.
  2. Fluctuating pressure during processing in pressure canner. 2. Maintain a constant temperature throughout processing time.
  3. Failure to work out air bubbles from jars before processing. 3. Remove by running a plastic spatula or knife between food and jar before applying lids.
  4. Imperfect seal. 4. Use new flat lids for each jar and make sure there are no flaws. Pretreat the lids per manufacturer’s directions. Use ring bands in good condition – no rust, no dents, no bends. Wipe sealing surface of jar clean after filling, before applying lid.
  5. Ring bands not tight enough. 5. Apply fingertip-tight over flat lid, but do not overtighten.
  6. Jars not covered with water in boiling water canner. 6. Jars should be covered with 1 to 2 inches of water throughout processing period.
  7. Starchy foods absorbed liquid. 7. Make sure dried beans are completely rehydrated prior to canning. Use hot pack for other starchy foods. Otherwise, none
  8. Food packed too tightly in jars cause boil over during processing. 8. Leave the appropriate headspace.
Problem Cause Prevention
Imperfect seal (discard food unless the trouble was detected within a few hours) 1. Chips or cracks in jar sealing surface. 1. Examine carefully before applying lid by observing and carefully rubbing finger around the mouth of the jar.
  2. Failure to properly prepare flat lids. 2. Follow manufacturer's directions.
  3. Particles left on mouth of jar. 3. A clean, damp cloth should be used before applying flat lids to remove any seeds, seasonings, etc.
  4. Using bad ring bands. 4. Use ring bands in good condition – no rust, no dents, no bends.
  5. Ring bands not applied to correct tightness. 5. Apply fingertip-tight over flat lid, but do not overtighten.
  6. Inverting jars after processing or lifting jars by tops while hot. 6. Use jar lifter for removing jars from canner, placing below ring band. Leave jars in upright position.
  7. Fat on jar rim. 7. Trim fat from meats. Add no extra fat. Wipe jar rim well.
Product dark at top of jar (not necessarily a sign of spoilage) 1. Air left in the jars permits oxidation. 1. Remove air bubbles before sealing jars. Use recommended headspace.
  2. Insufficient amount of liquid or syrup to cover all food in jar. 2. Cover product completely with water or syrup.
  3. Food not processed after filling jars and applying lids. 3. Process recommended length of time.
Problem Cause Prevention
Color changes that are undesirable 1. Contact with minerals such as iron, zinc or copper in cooking utensils or water. 1. Avoid these conditions by using carefully selected cooking utensils. Use soft water.
  2. Overprocessing. 2. Follow directions for processing times and operation of canners.
  3. Immature or overmature product. 3. Select fruits and vegetables at optimum stage of maturity.
  4. Exposure to light. 4. Store canned foods in a dark place.
  5. May be a distinct spoilage. 5. Process by recommended method and for recommended time.
  6. Natural and harmless substances in fruits and vegetables (pink or blue color in apples, cauliflower, peaches, or pears) 6. None.
Cloudy liquid (sometimes denotes spoilage) 1. Starch in vegetables. 1. Select products at desirable stage of maturity. Do not use overmature vegetables. If canning potatoes, use fresh boiling water to cover and not cooking liquid from preparing hot pack.
  2. Minerals in water. 2. Use soft water.
  3. Additives in salts. 3. Use pure refined salt (pickling or canning salt) without additives.
  4. Spoilage. 4. Prepare food as directed with published canning process. Process by recommended method and for recommended time.
Sediment in jars (not necessarily a sign of spoilage) 1. Starch in vegetables. 1. Select products at desirable stage of maturity.
  2. Minerals in water. 2. Use soft water.
  3. Additives in salts. 3. Use pure refined salt (pickling or canning salt) without additives.
  4. Yellow sediment in green vegetables or onions. 4. None (natural occurence).
  5. White crystals in spinach. 5. None (natural occurence).
  6. Spoilage. 6. Prepare food as directed with published canning process. Process by recommended method and for recommended time.
Problem Cause Prevention
Spoilage 1. Poor selection of fruits and vegetables. 1. Select product of suitable variety and at proper stage of maturity. Can immediately after harvest if possible.
  2. Incorrect processing temperature used. 2. Low acid vegetables and meats must be pressure canned for safety. Most fruits and pickles can be canned in boiling water. Process jams and jellies in a boiling water canner after filling jars.
  3. Incorrect process time. 3. Follow our research-based recommendations for canning foods. Follow directions for operation of canners and timing of processes. Do not overfill jars.
  4. Incorrect pressure. 4. Dial gauges should be checked every year for accuracy. Follow directions for operation of canners.
  5. Imperfect seal on jar. 5. Check jars and lids for defects before using. Wipe jar rim before closing. Do not overfill jars.
Floating (especially some fruits) 1. Fruit is lighter than sugar syrups. 1. Use firm, ripe fruit. Heat before packing. Use a light to medium syrup instead of heavy syrup.
  2. Air trapped in food pieces. 2. Use hot packs.
  3. Improper packing. 3. Pack fruit as closely as possible without crushing it. Release trapped air bubbles and readjust liquid level before applying lids. Make sure liquid covers food pieces completely.

 This document was adapted from "So Easy to Preserve", 6th ed. 2014. Bulletin 989, Cooperative Extension Service, The University of Georgia, Athens. Revised by Elizabeth L. Andress. Ph.D. and Judy A. Harrison, Ph.D., Extension Foods Specialists.

Recent Content

Can Splenda® (sucralose) be used in preserving food?

Granular Splenda® does not provide preservative properties like sugar. 

Canning Fruits:  Whereas we do not have published research work with using sucralose in the canning of fruits at home available to us, it is possible to use it for sweetening the water used to cover fruits when canning.  The texture and color preserving aspects of a sugar syrup will not be provided.  The result would be like canning in water except for the additional sweetness contributed by the Splenda®.  The USDA fruit canning directions do allow for canning in water (i.e., without a sugar syrup), as there is adequate preservation for safety from the heat of proper canning.  Some people do notice an aftertaste in other products and canned fruits, and it is possible some little changes in natural flavors may occur over storage time, since sugar can mask some of these.  For people used to sucralose sweetening and flavors, the aftertaste may not be an issue.  Based on some of our experiences in canning peaches and pickled foods, we suggest you start seeing what you like by trying less than a full substitution for the sugar in canning syrups.  For example, if you use a medium sugar syrup that is 5-/14 cups water to 2-1/4 cups sugar, try 1 to 1-1/4 cups Splenda® the first time.  You can always sweeten more when you serve the finished product if it is not quite sweet enough; then you can increase the canning liquid amount the next time you can.

Preserves and Pickled Fruits: In other cases, where sugar is important, like some preserves or pickled fruits, it is not recommended that substitution of Splenda® be used for sugar if the product is to be canned for shelf stability.  Splenda® cannot be used in several traditional Southern preserves we have on this website or in the University of Georgia Extension publications.  These are whole or uniform pieces of fruit in a very thick sugar syrup, usually made with figs, peaches or pears.  (These preserves are not jam or pectin gel products.)  Sugar is required for the preservation of these syrupy fruit preserves as published, with very short boiling water canner processes.  Without that heavy amount of sugar, these products become fruit pieces canned in water or lighter sugar syrups, and the usual (and longer) fruit canning process times and preparation directions would need to be used.

Jams and Jellies, or Fruit Spreads: You could use Splenda® as the optional sweetener in a jam or jelly made with a no-sugar needed pectin, such as Mrs. Wages™ Lite Home Jell® Fruit Pectin, Ball® No-Sugar Needed Pectin or Sure-Jell® for Less or No-Sugar-Needed Recipes.  With these low-methoxyl pectins, no sugar is required at all.  Sugar substitutes can be added as desired simply for flavor. The package inserts with these pectins give instructions on when to add the sugar substitutes (usually after all the cooking, right before filling the jars).  Do not try to substitute Splenda® for the required sugar in recipes calling for “regular” liquid and powdered pectins.  

And do not try to substitute Splenda® in long-boil or no-pectin-added jams and jellies intended for room temperature storage as a canned product.  You might get some thickened fruit spreads with just fruit and Splenda®, but they may not have enough water control for processing like a gelled, high sugar-containing jam or jelly.  They might require longer processing to avoid spoilage at room temperature.  If you want to experiment with making these kind of fruit spreads we recommend freezing or refrigeration for storage. 

We have developed three recipes using Splenda® and they are on our website, www.homefoodpreservation.com. They are quick pickled sweet cucumber slices, pickled beets and pickled cantaloupe.  They are under the How do I....Pickle category, as well as National Center factsheets, http://www.uga.edu/nchfp/publications/nchfp/factsheets.html.

There is also a Peach-Pineapple Reduced Sugar Fruit Spread from the USDA Complete Guide to Home Canning that does not require added sugar.  Some other fruit substitutions are provided in the text.  The suggested sugar for sweetening can be left out, or you can add some Splenda® as desired for sweetness.  The process time is longer than regular jams and jellies, and is like that for a fruit puree. http://www.uga.edu/nchfp/how/can_07/peach_pineapple_spread.html

How can I become a Master Food Preserver?

“Master” volunteer programs that are connected to the Cooperative Extension System, such as Master Food Preservers and Master Gardeners, are currently state- or county-managed programs affiliated with the land grant universities and the Cooperative Extension Service in the state. In exchange for extensive education, the master volunteer returns contributions to the local Extension office, such as answering phone calls, developing and hosting exhibits, judging at competitions, etc. There are liabilities involved in someone conducting even volunteer work in the name of a state university; therefore, the guidelines and management procedures will vary among states. At this time, the National Center is not in a position to help individuals meet state guidelines for credentials and the title of Master Food Preserver.

If you would like to find out if your state offers this opportunity to become a Master Food Preserver, contact your local Extension Office (usually listed in local government pages of the phone book under Cooperative Extension Service, Ag Extension Office and/or 4-H Office). You could also contact someone at the state university to either ask your questions or let them know of your interest. These contacts can be found on a website managed by USDA:

Most states do not sell their Master Food Preserver curricula or notebooks to the general public. If someone wants information on preserving, they have other publications available with the actual recommendations and procedures. This website from the National Center is full of “How To” information for various types of food preservation. We will eventually have tutorials and a correspondence type course on line for self-study.

Is it necessary to thaw meat or fish before cooking?

No, meat and fish can be cooked from the frozen state if extra cooking time is allowed. The amount of time will depend on the size and shape of the cut. Large frozen roasts can take as much as 11/2 times as long to cook as unfrozen cuts of the same weight and shape. Small roasts and thin cuts such as steaks and chops require less time.

Can meat and poultry be thawed in the conventional oven?

No, meat and poultry should never be thawed in the conventional oven or at room temperature. There is greater danger of bacterial growth and food spoilage for food thawed at room temperature. Thaw meat and poultry in the refrigerator in the original wrappings. To speed thawing, loosen the wrapping. To keep other foods safe, put the thawing meat and poultry in a pan on the bottom shelf. For a quicker method, immerse meat or poultry in a watertight bag into cold water. Thaw until it is pliable. Meat and poultry can also be thawed quickly and safely in the microwave oven, followed by immediate cooking, either in the microwave oven or by some other method. Because microwave ovens vary, check your manufacturer's instructions for information on how to safely thaw in your microwave oven. Frozen meat and poultry can also be cooked without thawing.

What is blanching?

Heating or scalding the vegetables in boiling water or steam for a short period of time.

Is it recommended to blanch vegetables before freezing?

Yes. Blanching slows or stops the action of enzymes which cause loss of flavor, color and texture. Blanching cleanses the surface of dirt and organisms, brightens the color and helps retard loss of vitamins. Blanching also wilts or softens vegetables and makes them easier to pack.

Is it safe to freeze fruits without sugar?

Yes; sugar is not used as a preservative but only to maintain flavor, color and texture.

Can artificial sweeteners be used in place of sugar for freezing fruits?

Sugar substitutes can be used in place of sugar. Labels on the products give the equivalents to a standard amount of sugar. Follow the directions to determine the amount of sweetener needed. Artificial sweeteners give a sweet flavor but do not furnish beneficial effects of sugar, like thickness of syrup and color protection.


The University of Georgia Cooperative Extension has now published a 6th edition of its popular book, So Easy To Preserve. The book was reviewed and updated in 2020. Chapters in the 388-page book include Preserving Food, Canning, Pickled Products, Sweet Spreads and Syrups, Freezing and Drying.