Home Canning Troubleshooting Guide

If your home canning efforts haven't entirely met with success, try using this troubleshooting guide to resolve your specific problem and avoid others in the future.

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Home canning doesn't always go this well, but with a little troubleshooting help you should be able to overcome whatever problems you're having.


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(Reprinted with permission from the Ball Blue Book (30th Edition), copyright © 1979 by Ball Corporation.

Now that most folks have their gardens in — and, in some areas, are already harvesting their first crop — it's time to think about putting up some of those delicious homegrown goodies . . . for year-round enjoyment and lower winter food bills.

Home canning food can be as easy as it is rewarding.

There are, however, some difficulties that occasionally plague even the most experienced canner. The troubleshooting guide below will tell you just what might have caused your past batches of preserved goodies to turn out not quite as you expected, and how to avoid similar preserving problems this summer.

Remember, too, that spoiled food should never be eaten. The most obvious signs of dangerous spoilage include gas bubbles and spurting liquid ... soft, mushy, slimy, or moldy food . . . cloudy liquid (or liquid with sediment in it) .. . leaking jars . . . bulging lids . . . and unnatural odors and colors.

For safety's sake, be sure to boil all of your canned low-acid foods at least 15 minutes before you taste them. If the liquid foams or if the food has an unnatural odor when it's heated in this manner, the dish is very likely to be spoiled . . . and should definitely be discarded!

Condition: Foods Darken in Top of Jar

CAUSE: Liquid did not cover food product.  

PREVENTION: Cover food product with liquid before capping jar. (See "Loss of liquid" reference.)

CAUSE: Food not processed long enough to destroy enzymes. 

PREVENTION: Process each food by recommended method and for recommended length of time.

CAUSE: Manner of packing and processing did not produce a high vacuum.

PREVENTION: Pack and process as recommended.

CAUSE: Air was sealed in the jars either because head space was too large or air bubbles were not removed. 

PREVENTION: Use recommended head space. Remove air bubbles by running nonmetallic kitchen utensil between food and jar.

Condition: Fruits Darken After They Have Been Removed From Jar

CAUSE: Fruits have not been processed long enough to destroy enzymes.

PREVENTION: Process each fruit by recommended method and for recommended length of time. Time is counted when water reaches a full boil in the canner.

Condition: Corn Is Brown

CAUSE: Corn was too mature for canning.

PREVENTION: Use freshly picked corn which has plump, shiny kernels filled with milk.

CAUSE: Liquid did not cover corn.

PREVENTION: Cover corn with liquid before capping jar. (See "Loss of liquid" reference.)

CAUSE: Jars were processed at too high a temperature.

PREVENTION: Keep pressure in canner at recommended pounds... gauge may be faulty and should be checked.

CAUSE: Variety of corn used.

PREVENTION: Use different variety next time.

Condition: Pink, Red, Blue, or Purple Color in Canned Apples, Pears Peaches, and Quinces

CAUSE: A natural chemical change which occurs in cooking the fruit.


Condition: Green Vegetables Lose Their Bright Green Color

CAUSE: Heat breaks down chlorophyll, the green coloring matter in plants


Condition: Some Foods Become Black, Brown, or Gray

CAUSE: Natural chemical substances (tannins, sulfur compounds, and acids) in food react with minerals in water or with metal utensils used in preparing food.

PREVENTION:  Use soft water. Avoid using copper, iron, chipped enameled ware, or utensils from which tinplate has worn.

Condition: Green Vegetables Turn Brown

CAUSE: Vegetables were overcooked. 

PREVENTION: Time precooking and processing exactly.

CAUSE: Vegetables were too mature for canning.

PREVENTION: Asparagus tips should be tight and the entire green portion tender. Pods of green beans should be crisp and meaty and the beans tiny. Peas, lima beans, and all other beans and peas which are shelled should be green.

Condition: Crystals in Grape Products

CAUSE: Tartaric acid which is naturally found in grapes.

PREVENTION: Carefully ladle juice into clean hot jars, cap, and reprocess original length of time.

Condition: Yellow Crystals on Canned Green Vegetables

CAUSE: Glucoside, natural and harmless substance, in vegetables.


Condition: White Crystals on Canned Spinach

CAUSE: Calcium and oxalic acid in spinach combine to form harmless calcium oxalate.


Condition: White Sediment in Bottom of Jars of Vegetables

(May denote spoilage.)

CAUSE:  Starch from the food.


CAUSE:  Minerals in water.

PREVENTION:  Use soft water.

CAUSE: Bacterial spoilage. Liquid is usually murky, food soft. (Do not use.)

PREVENTION: Process each food by recommended method and for recommended length of time.

Condition: Fruit Floats in Jar

CAUSE: Fruit is lighter than the syrup.

PREVENTION: Use firm, ripe fruit. Heat fruit before packing it. Use a light to medium syrup. Pack fruit as closely as possible without crushing it.

Condition: Cloudy Liquids

(May denote spoilage.)

CAUSE: Spoilage. (Do not use.)

PREVENTION:  Process each food by recommended method and for recommended length of time.

CAUSE: Minerals in water.

PREVENTION: Use soft water.

CAUSE: Starch in vegetable.


CAUSE: Fillers in table salt.

PREVENTION: None, except using a pure refined salt.

Condition: Loss of Liquid During Processing

(Food may darken, but will not spoil. Do not open jars to replace liquid.)

CAUSE: Food not heated before packing.

PREVENTION:  Heat food before packing. Pack food more loosely.

CAUSE: Food packed too tightly.

PREVENTION: Pack food more loosely.

CAUSE:  Air bubbles not removed before capping jar.

PREVENTION:  Remove air bubbles by running nonmetallic kitchen utensil between food and jar.

CAUSE: Pressure canner not operated correctly.

PREVENTION:  Pressure should not be allowed to fluctuate during processing time. Allow pressure to drop to zero naturally... wait 2 minutes before opening lid.

CAUSE: Jars not covered with water in boiling water bath canner.

PREVENTION:  Jars should be covered 1 inch with water in canner throughout the processing period.

CAUSE: Starchy foods absorbed liquid.


Condition: Jar Seals, Then Comes Open. Spoilage Evident

(Do not use.)

CAUSE: Food spoilage from under processing.

PREVENTION: Process each food by recommended method and for recommended length of time.

CAUSE: Disintegration of particles of food left on the sealing surface.

PREVENTION:  Wipe sealing surface and threads of jar with clean, damp cloth before capping.

CAUSE: Hairline crack in jar.

PREVENTION: Check jars... discard ones unsuitable for canning.

Condition: Jar of Food Fails to Seal

(Correct cause and reprocess the full time or use the food immediately.)

CAUSE: Many factors could be involved, such as failure to follow instructions for using jar and cap, or a bit of food forced up between the jar and lid during processing.

PREVENTION:  Carefully follow methods and instructions for using jars and caps and for foods to be canned. For more information, request the free pamphlet "Home Canning Basics" from Ball Corporation.

Condition: Hollow Pickles

CAUSE: Cucumbers were stale when pickling was begun.

PREVENTION:  Pickling process should be started within 24 hours of picking cucumbers.