CHAPTER 2: Troubleshooting Canning Problems

Canning requires strict adherence to directions, and many problems can result from not following recipes precisely. If you are new to canning, you may be tempted to come up with your own canning recipe or add extra thickeners, vegetables, or liquids to your food — resist the temptation. Canning recipes have been developed and tested to ensure a delicious, quality product that will withstand the stress of canning, and will provide healthy food even after long storage.

There are common mistakes that people make during canning. This chapter focuses on how to examine your finished products for problems, and what to do when you see a problem. Not every funny-looking jar must be discarded; sometimes, the problem is minor or just a symptom of produce subjected to high temperatures. However, the rule is: if in doubt, throw it out.

Here are some other mistakes people often make while canning:

• Failing to adjust the recipe for their altitudes.

• Forgetting to vent the pressure cooker.

• Neglecting to have their pressure cooker gauges checked and adjusted before each canning season.

• When processing “hot pack” foods, allowing the food to cool before placing it in jars.

Check Your Food!

When you open up a jar of food, there are several things to check for to ensure your food has not spoiled. Look for the following indications:

1. The outside of the jar is soiled or moldy. This means that food has seeped out of the jar through a bad seal — and therefore mold and bacteria have seeped in. Toss it out.

2. Bubbly liquid or a spurt of liquid when you open the jar. This means that food has developed gases through improper processing.

3. Change in texture or color — this indicates the food has spoiled since canning.

4. Mold on the lid or in the food. An improper seal or processing has allowed mold spores to grow.

Common Canning Problems

Because the canning process requires several steps and careful attention to details, many things can go wrong with your food. In addition, before you eat food from any jar, check it again for problems. Once you complete a batch of canning and allow it to cool for 24 hours, check each jar for problems. Do not diagnose problems by tasting the food.

This guide will describe some common problems, how they occurred, and how to avoid these problems next time. Some of the problems are merely appearance issues, but other problems will affect the taste or texture of the food and hamper your enjoyment of your products.

However, some of the problems are health issues. These are the most important problems for you to monitor. Once you complete a batch of canning, always check your food against these health signs to be sure you do not harm anyone with the food. If you see signs that food has become contaminated, take care with your disposal method. Some bacteria are deadly even in small amounts; you could spill a tiny splash on your hand and then wipe your mouth. Then, the bacterium has entered your system. It is best to dump bad products down the drain, where the water treatment plants will neutralize contaminants, then scrub your sink and sterilize the jars. Make sure you always discard the self-seal lids after using them. The screw ring can be re-used once it is sterilized. Alternatively, you can boil the jars in a water bath canner for 30 minutes to neutralize the contents, and then place the unopened jars in the trash.

Spoiled food

Spoiled food usually has several indicators; just one sign might not be a problem. For example, some foods, such as juices, may be cloudy after processing because of the pulp present in the juice. However, if you open the jar and the food smells off, rather than the food’s ordinary smell, or if you see feathery mold growing on the rim or in the jar, it is clearly a spoiled product. For this reason, if you notice something odd with the food, check for anything else that may indicate a problem: the color, smell, increase in bubbles, seepage from the jar, obvious growth of bacteria or contaminants, etc. Remember; do not test food by tasting it.

If you notice the following problems with your jars, carefully discard the food and lid, and sterilize the jar immediately. It is better to lose a little food than make yourself sick. To prevent these problems in the future, take these precautions to process the food properly in the future:

• Make sure the jars are not overstuffed and that they are filled to the proper headspace. Remove air bubbles before putting the lids on the jars.

• Follow the processing method and time exactly.

• Check to be sure you have a good seal: concave, good vacuum, and no bulging at the lid.

• Make sure the pressure gauge on your pressure canner is checked and calibrated for accuracy at the beginning of each canning season.

• Check jars and lids for cracks, chips, rust, or damage. Always use new lids and sterilized equipment.

• Choose the freshest foods that have no rotten or moldy parts. Prepare the product properly.

• Carefully wipe the rim of each jar after it is filled. Make sure no food remains on the rim to hamper the seal or cause spoilage later.

Illustration courtesy of the USDA

Problem	Possible Causes
Product at the top of the jar is dark and/or thicker than normal.	This may not be a sign of spoiled food; check the table on appearance changes to rule out other problems. If other signs of spoilage exist, this is probably the result of improper processing.
The liquid in the jar is cloudy.	This may not be a sign of spoiled food; check the table on appearance changes to rule out other problems. If other signs of spoilage exist, this is probably the result of improper processing.
The liquid in the jar contains sediment.	This may not be a sign of spoiled food; check the table on appearance changes to rule out other problems. If other signs of spoilage exist, this is probably the result of improper processing.
Non-pickled or fermented food has a sour, strange, or foul smell.	The food or jar has been contaminated — especially if bubbles also appear within the jar.
Non-pickled or fermented food is bubbly.	The food or jar has been contaminated and fermentation has occurred, especially if the food has a strange or foul smell.
Food has an unusual color.	This may not be a sign of spoiled food; check the table on appearance changes to rule out other problems. If other signs of spoilage exist, this is probably the result of improper processing.
Jar lid, rim, or the surface of the food contains mold.	Although some molds are harmless and can be removed so the rest of the food can be eaten, it is best to be safe and discard the entire contents. This is the result of improper processing.

Cleaning up the area

Courtesy of the USDA

Contact with botulinum toxin can be fatal whether it is ingested or enters through the skin. Take care to avoid contact with suspect foods or liquids. Wear rubber or heavy plastic gloves when handling suspect foods or cleaning up contaminated work surfaces and equipment. A fresh solution of 1 part unscented liquid household chlorine bleach (5 to 6 percent sodium hypochlorite) to 5 parts clean water should be used to treat work surfaces, equipment, or other items, including can openers and clothing, that might have come in contact with suspect foods or liquids. Spray or wet contaminated surfaces with the bleach solution and let stand for 30 minutes. Wearing gloves, wipe up treated spills with paper towels being careful to minimize the spread of contamination. Dispose of these paper towels by placing them in a plastic bag before putting them in the trash. Next, apply the bleach solution to all surfaces and equipment again, and let stand for 30 minutes and rinse. As a last step, thoroughly wash all detoxified counters, containers, equipment, clothing, etc. Discard gloves when cleaning process is complete. (Note: Bleach is an irritant itself and should not be inhaled or allowed to come in contact with the skin.)

Problem	Possible Causes	How To Avoid
Product at the top of the jar is dark and/or thicker than normal.	Too much air in the jar has caused the top layer of food to become oxidized.	Do not overstuff jars, but be careful that the food and liquid reach the recipe’s proper headspace. Remove bubbles from the jar before processing.
	The food in the jar is not completely covered with liquid.	Do not overstuff jars, but be careful that the liquid completely covers the food and reaches the recipe’s proper headspace.
	Food is spoiled, because it was not processed correctly.	Follow preparation and processing instructions exactly.
Food has an unusual color.	Some substances in foods react to the canning process by changing color. For example, peaches, pears, cauliflower, or apples may turn slightly pink or blue.	Freezing, drying, and pickling (flowers).
	Food that is white, blue, black, or green ( unless it is naturally that color) is spoiled. If other signs of spoilage exist, the food has been contaminated.	Follow preparation and processing instructions exactly.
Food has pale color.	The jars have been stored improperly.	Store the jars in a cool, dark place, free from drafts or excess humidity.
The liquid in the jar is cloudy.	Minerals or additives in the water or salt may have clouded the liquid.	Choose pure salt with no additives, and use soft or distilled water for canning.
	The starchy foods have released some starch, which has clouded the liquid. Meat products often produce cloudy liquid during processing; this is normal.	Choose fresh, ripe products that are not overripe. If cutting up starchy foods like potatoes, rinse them in cold water before processing; then when you add liquid to the jars, use fresh water instead of the cooking water.
	If the product is juice, it is possible that extra pulp has drained into the juice.	This is not a problem — the pulp will add extra flavor and nutrients to the finished product. However, if you prefer a clear juice, strain the juice several times before processing, and do not squeeze or press the pulp while straining.
	If other signs of spoilage exist, the food has been contaminated.	Follow preparation and processing instructions exactly.
The liquid in the jar contains sediment.	Minerals or additives in the water or salt may have clouded the liquid.	Choose pure salt with no additives, and use soft or distilled water for canning.
	If other signs of spoilage exist, the food has been contaminated.	Follow preparation and processing instructions exactly.
Food is floating in the jar.	The syrup used in canning is heavier than the product.	Prepare ripe, firm fruit properly, and use the hot pack method. Use thinner syrup that contains less sugar.
	The produce or jar contains too much air.	Use the hot pack method to remove more air from the product. Make sure all bubbles are removed from the jar before processing. Pack the produce firmly in the jar.
Tomato juice has separated into yellow liquid on top and thick red juice at the bottom.	This is a natural enzymatic action that occurs when tomatoes are cut up for processing.	If you prefer not to shake up the jar before pouring some juice, make sure that during the hot pack process, you bring the tomatoes to a boil immediately after chopping them.

Jar is not sealed properly

If you discover any of the following problems, you can refrigerate the food and eat it within a few days. Alternatively, if you discover a bad seal within the first 12 to 24 hours, and the band and lid are undamaged, you can re-process the jar using the original method and timing.

Problem	Possible Causes	How To Avoid
Not enough liquid in jars.	Uneven pressure in the pressure canner.	Make sure pressure remains constant during processing. Allow pressure canner to release the pressure and heat naturally. Wait at least 10 minutes before opening the canner.
	Bubbles were left in the jar while packing food.	Slide a knife or spatula inside the jar to remove air bubbles; adjust headspace if necessary.
	Liquid escaped through a bad seal.	Use new, undamaged lids and ring bands that screw on properly. Make sure the jars do not have any chips or cracks. Make sure no food is on the rim of the jar by wiping the rims before putting on the lids. Wipe sealing surface of jar clean after filling, before applying lid.
	The water bath canner did not have sufficient water.	Make sure the water is at least 2 inches over the tops of the jars throughout the entire processing time.
	The food absorbed too much liquid.	Starchy foods will need a larger ratio of liquid to product. Make sure you hot pack these items.
	The food was packed too tightly.	Allow enough headspace so that the food does not boil out of the jars.
The jar did not seal; the lid is not concave and does not have a vacuum seal.	There was food between the rim and seal, or the rim was damaged.	Check jars before using. Wipe the rims of jars after filling them.
	Ring bands were damaged or not screwed on properly.	Check ring bands before using. Always screw bands on finger-tight.

Special problems with jams and jellies

Problem	Possible Causes	How To Avoid
The product contains crystals.	Too much sugar might have been added, or the sugar was not completely dissolved during processing.	Reduce the amount of sugar; follow tested recipes exactly and remove from heat once the product reaches the jellying point.
	If appearing in products made from grape juice, naturally occurring tartrate crystals may have formed.	Settle the crystals in the juice by refrigerating overnight and then straining the juice before making the product.
Bubbles.	Jelly set while air bubbles were still in the jar.	Skim foam from the liquid before filling jars, and quickly slide a spatula through the product to remove air bubbles.
	If other signs of spoilage exist, the food has been contaminated.	Follow preparation and processing instructions exactly.
Jam or jelly is too soft.	There may be several causes: The juice was overcooked. Too much water was used to make the juice. The sugar and juice proportions were not correct. The product was undercooked, so that the sugar was not concentrated enough.	Follow tested recipes exactly.
	The product did not contain enough acid.	Add a small amount of lemon juice to the juice before making the jam or jelly.
	Making too much jelly/jam at once.	Process jams and jellies in small batches, such as 4-6 pint jars at a time. You will need approximately 8-12 cups of fruit juice to produce 4-6 pint jars; follow recipes for specific amounts.
	Not allowing enough time before moving jars.	Wait at least 12 hours after processing before you move the jars.
	Using the product before it has had time to properly gel.	Most jams or jellies will take about two weeks to completely gel; jellies take a little longer than jams. Some fruits, such as plums, will take longer than two weeks; fruit butters will not completely gel. Shaking the jar might help you determine if the product is ready.
The product is darker than normal.	The juice may have cooked too long, or the sugar may have scorched.	Follow the instructions precisely; smaller batches of product will be easier to manage.
	The jam or jelly may be too old, or may have been stored in a very warm environment.	Once the product has set, store it in a cool, dark place and use within the next year. Refrigerate the jar after it has been opened.
The product is cloudy.	The juice used to make the jam/jelly has too much pulp drained into the juice.	This is not a problem — the pulp will add extra flavor and nutrients to the finished product. However, if you prefer a clear juice, strain the juice several times before processing, and do not squeeze or press the pulp while straining.
	The completed jelly/jam sat before it was poured into the jars, or was poured too slowly.	The product will begin to gel immediately upon removal from the heat. Pour into the jars quickly and carefully.
The jam or jelly is stiff or too thick	The product has been overcooked so that too much of the liquid has boiled away.	Follow cooking instructions precisely and stop cooking once the product forms a sheet on the cooking spoon.
	Inaccurate proportion of pectin to fruit.	Use less pectin; tested recipes should not present this problem.

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