How to Can Soups | College of Agriculture, Forestry and Life Sciences (2024)

FAQs

What happens if I leave too much headspace when canning? ›

If too much headspace is allowed, the food at the top is likely to discolor. Also, the jar may not seal properly because there will not be enough processing time to drive all air out of the jar.

REMEMBER: If you are canning low-acid foods such as vegetables, broth, and meats, you WILL need a pressure canner. However, if you are canning high acid foods like jams and jellies, fruits (like canning peaches), applesauce, pickles, etc., you can use safely and confidently water-bath canning.

As long as the can is in good shape, the contents should be safe to eat, although the taste, texture and nutritional value of the food can diminish over time. Home canned foods should be used within 1 year.

For vegetable soup, fill the jars half full of solids, add broth allowing 1 inch headspace and process in a pressure canner. There needs to be space for the hot liquid to circulate between the food particles.

"When air bubbles are not removed, the air trapped by the food will essentially add to the headspace. Too much headspace can lead to seal failures." Opt for wooden or plastic tools (like Ball's official "bubble freer," shown here) when shifting the contents to remove headspace.

Most shelf-stable foods are safe indefinitely. In fact, canned goods will last for years, as long as the can itself is in good condition (no rust, dents, or swelling). Packaged foods (cereal, pasta, cookies) will be safe past the 'best by' date, although they may eventually become stale or develop an off flavor.

Low-acid foods are the most common sources of botulism linked to home canning. These foods have a pH level greater than 4.6. Low-acid foods include most vegetables (including asparagus, green beans, beets, corn, and potatoes), some fruits (including some tomatoes and figs), milk, all meats, fish, and other seafood.

Bring to a rolling boil, cover the canner and boil for 10 minutes if using 4-, 8- or 12-ounce jars or for 15 minutes if using 16-ounce jars. (Check individual preserve recipes for more specific processing times.) Let cool for 10 minutes before removing the jars from the pot.

Placing room-temperature jars in boiling water gradually raises their temperature, reducing the risk of glass breakage due to rapid heating. This precaution ensures that both the jars and their contents remain intact throughout the canning process.

How do you enhance a can of soup? ›

Go green: Add some spinach or chopped kale or pesto. Get zesty: A squirt of lemon juice or zest could brighten up an otherwise flat soup. Starchy things: Homemade croutons, crushed tortilla chips, or oyster crackers. Clean out the fridge: got cooked beans or rice, a dollop of sour cream, or a splash of heavy cream?

Jars of high-acid foods that are inverted after being filled, instead of being safely processed in a water bath, will fail to seal properly. Inverting the jars is an old-fashioned and unsafe method that is, unfortunately, still recommended in many current home-canning cookbooks.

Headspace is the distance between the surface of food and the underside of the lid. Leaving the specified amount of headspace in a jar is important to assure a vacuum seal. If too little headspace is allowed the food may expand and bubble out when air is being forced out from under the lid during processing.

Canning recipes will always call for a specific headspace to leave when you're filling jars. Headspace is the space from the top of the food in the jar to the top of the rim. An overfilled or underfilled jar may not seal correctly, which, as you now know, results in unsafe food. It's all about the seal.

If too little headspace is left, food may boil up and out of the jar, preventing a seal. If too much headspace is left, the processing time may be inadequate to drive off the oxygen within the jar, preventing the seal from forming.”

Overfilling jars not only encourages liquid loss but increases the risk of seal failure. During heat processing contents of the jar expand. Too little space between the lid and food/liquid forces liquid out of the jar when it is heated. Use correct headspace when filling jars.