Photo by Stephanie Staton
A number of problems can occur during the canning process, so it's good to be equipped with a backup plan.
I’ve had my share of canning disasters. Canning isn’t complicated, but upset the chemistry of pectin and sugar or skip a step in the process, and you may find yourself in, well, a jam.
Theresa Loe is the resident canning expert and associate producer for PBS’s Growing a Greener World. She’s been canning food all her life, and her blog, Living Homegrown Fresh, covers food preservation as well as urban gardening. Loe says she first learned how to can at her mother’s apron strings, but she extended that knowledge through training in a master food-preserver program, attending culinary school, and keeping up with the latest USDA recommendations and guidelines. Here’s her advice for avoiding or, when possible, fixing canning efforts that have gone awry.
1. Problem: Jelly Won’t Gel
“Jellies ‘gel’ because of a perfect ratio between the acid, pectin and sugar of the mixture. If the proper ratio isn’t achieved, you get a runny jelly,” says Loe. That ratio can be upset when the fruit you’re using doesn’t have enough natural pectin, which can happen with overripe fruit, or when you’ve reduced the amount of sugar or skipped the lemon juice that some recipes call for. You must have a perfect balance of sugar, acid and pectin.
The fix: To ensure gelled jellies, Loe suggests following a proven, reliable recipe to the letter—without adjustments. Make sure your fruit is picked at its prime, before it gets too ripe—the pectin level of fruit drops as the fruit ripens.
If you have a batch that doesn’t gel, you have a couple of options.
“If it’s a small batch, use it as syrup on pancakes, waffles and in cooking. I usually only remake runny jelly if I have a large batch or two that didn’t work,” says Loe.
If you decide to re-batch, you’ll need to open the jars and pour all of the contents back into your pot; add sugar, lemon juice and pectin; cook it again; and reprocess it.
“It usually works,” says Loe, but she cautions that you might end up with a rubbery consistency after reprocessing.
A caveat: Don’t rush to judgment. Some jellies and jams take a little longer to set than others. If it still has a syrupy consistency after it’s completely cooled, then it probably won’t set up, and you can try re-batching it.
2. Problem: Jelly Gels Too Much
Photo by Stephanie Staton
Overcooking or an excess of pectin can result in overly firm jam or jelly.
The culprit: Too much pectin or overcooking your jelly or jam will cause it to be overly firm.
“People are surprised by the delicate balance between the ratios of sugar, acid and pectin. If you have too much pectin compared to the sugar and acid in the mix, you get overly firm jelly or jam,” says Loe. “Also, if your fruit was [not fully ripe] and you added commercial pectin, you may have upset the ratio.”
The fix: Make sure your fruit is at its prime, or that you have a mixture of less-mature fruit combined with ripe fruit. And be careful to time your cooking precisely.
“If you cook the mixture too long,” explains Loe, “you evaporate too much of the water, and the jam or jelly gets too firm.”
If your jelly or jam ends up too firm, there’s really no fix.
“You can use it for cooking rather than as a spread,” suggests Loe. “If you place some in a small saucepan with a little water and melt it down, you can use it in sauces or as a topping for waffles or ice cream. But you really can’t re-can it.”
3. Problem: Lids Don’t Seal or Release Their Seal
Photo by Stephanie Staton
Make sure your jars lids sealed properly during the canning process. If you catch unsealed jars in 24 hours, then reprocess.
The culprit: Often, this will happen if there’s a nick in the jar rim or if you don’t completely wipe the food from the rim. The rim needs to have complete contact with the lid to seal properly.
Another reason is too much headspace.
“Headspace is the space between the food and the top of the jar,” says Loe. “Too much space can make it difficult for the jar to create the vacuum seal. The air inside the jar reaches a certain temperature during processing, cools and then escapes, causing the vacuum seal that sings out that ‘ping.’ But only so much air can come out successfully. If there’s too much headspace, there won’t be a vacuum, or it will be a weak vacuum that will gradually release on the shelf.”
Lid manufacturers also recommend placing your lids in a pot, covering lids with water and bringing the water to a simmer, then keeping the lids hot until you’re ready to use them. Do not boil your lids: This can cause the seals to fail.
The fix: “If the problem was discovered within 24 hours, you can reprocess the food,” says Loe.
Remove the band and lid, and check the top of the jar for nicks. If there are any nicks, put the food in a new, sterile jar. Wipe down the jar’s rim to remove any food particles and check the headspace to be sure you’re following the recipe’s guidelines. Add a new lid and band, and reprocess the jars for the full amount of time.
4. Problem: Canning Process Is Interrupted by a Power Outage
The culprit: In this case, chalk one up to Murphy’s Law.
The fix: If you have power within 24 hours, start the processing time over as soon as the power comes back on, and process the jars for the full time all at once. It may affect the food’s texture (i.e., pickles may lose crispness), but it depends on the food and the processing time.
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