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Southern States' Home Canning Series:
Article 4 - Troubleshooting Problems
Sometimes, even those who have been home canning for years may run
into problems with their food-filled jars. Some problems are related
to the condition of the jars or lids and/or how they were filled.
Others relate to spoilage of the food or changes the food may have
undergone during processing. We present the following information
to help you troubleshoot what may have gone wrong if you encounter
a problem.
Jars Won't Seal
The most common problem encountered by home canners is jars that
do not seal properly. If jars do not seal during cooling, the food
may be repacked with a new lid and the jars processed again for
the entire amount of processing time in the recipe. If only one
jar did not seal, refrigerate it and use the contents within 2 days.
There are several causes which often prevent jars from sealing.
These include: overfilling of the jar, chipped jar rims, particles
of food on the jar rims (from improperly wiped jars) coming between
the surface of the rim and the sealing compound in the lid, lids
being too hot or too cold, scratches across the sealing compound
in the lid, screw bands being tightened after jars are removed from
the canner thus breaking the seals, bent or rusty screw bands not
holding the lid against the jar rim tightly enough during processing.
 Cosmetic
Problems
Other problems are simply changes in the food which change the
cosmetic appeal of it but do nothing to the nutritional quality.
When sediment appears in the bottoms of jars, it may simply be
minerals in the water used for filling the jars or precooking the
food. If the food contains a significant amount of starch, such
as corn or beans, some of the starch may have settled out of the
food. If there is sediment in a jar of fruit, the fruit was most
likely overripe at the time of processing. When table salt containing
an anti-caking ingredient is used instead of the proper pickling
salt, you may find sediment at the bottom of your jar of pickles.
Foods may change color because they were not processed long enough
to kill color changing enzymes. Over processing can cause color
changes too. Color changes in fruits, such as pears or peaches,
are most likely due to them being left untreated with an ascorbic
acid color keeper during preparation. Some foods with lots of color
in them, like beets, may leach some of their color into the surrounding
liquid or syrup. Contact with air may discolor food if the jar was
not filled with enough liquid and the top portion of food dries
out or if air bubbles are not removed prior to processing. Food
stored in a warm room or exposed to strong light may also discolor.
If food floats to the top of the jar, it may have been packed too
loosely or processed too long. If fruit, it may have been too ripe
or the syrup may be too heavy for it. Raw-packed food that has been
left uncooked tends to float more than partially cooked food. Uncooked
food contains more air than cooked food.
Liquid levels may be too low after processing if jars were too
full or packed too tightly. This causes the food to boil over during
processing and a siphoning action occurs. Liquid may be too low
if air bubbles are not removed before processing. Sometimes, starchy
foods will absorb water which creates lower liquid levels. Processing
problems, such as fluctuating pressure within a pressure canner
or water less than one in above the tops of jars in a water-bath
canner also can cause low liquid levels in the finished jars.
Spoilage
Spoilage of food is a serious problem which can result in food
poisoning. If food was underprocessed, yeast and toxin causing bacteria
may not have been totally destroyed. Some toxin producing microorganisms
can grow within an airtight jar. Inspect each jar of home canned
food carefully before consuming the contents. Discard the food if
there are patches of mold on it or if it is foamy or murky in appearance.
A leaking jar should also be discarded. The food should smell pleasant
and like the food that was canned. If it does not smell or look
right, throw it out.
Bacteria which cause botulism toxin can be present in a sealed
jar without changing the look or smell of the food if the jars were
processed incorrectly. If you suspect your home canned food may
contain botulism toxin, boil it uncovered for 10 minutes (20 for
spinach and corn) to destroy the toxin. If it has spoiled, an unpleasant
odor will most likely be produced. If it smells OK after boiling
it is safe to eat, but "when in doubt, throw it out" still
applies. **Never taste foods with low acid
content directly from the freshly opened jar.**
Home canned foods spoil when processed incorrectly. Pressure in
the pressure canner may not have been properly maintained at 10
pounds during processing either because the gauge was not accurate,
the heat under the canner became too low and pressure dropped or
no altitude correction was made to the processing time at altitudes
above 2,000 feet. Air may not have been sufficiently exhausted from
the pressure canner before the weight was placed over the vent to
build the pressure up. In a water-bath canner, the water may not
have been at a full boil for the entire processing time or the water
level dropped below the tops of the jars.
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