‘Preserving the taste of summer’

Aug 19, 2023

-Messenger photo by Kelby WingertHolly Van Heel, human sciences specialist for food and health at the Webster County Iowa State Extension and Outreach office, shows a pressure canning lid with a numbered pressure gauge. Community members can take their pressure canning gauges into the Webster County Extension office to have them tested for accuracy at any time.

As the summer garden growing season comes to an end, many gardeners are looking at baskets and buckets full of more produce than they know what to do with. Canning is a very popular method of food preservation to save that taste of summer long after the temperatures start to fall.

However, when it comes to preserving food, important safety measures need to be taken to prevent disastrous results, including dangerous bacteria growth.

“When in doubt, throw it out,” is the first rule of canning, said Holly Van Heel, human sciences specialist for food and health at Iowa State University Extension and Outreach’s Webster County office.

If properly preserved and stored in a dry, cool place, home-canned food items will last a year, Van Heel said.

Just about any food can be canned. Everything from fruits and vegetables to salsa and sauces. Even meat, poultry and wild game can be canned.

When it comes to canning food, Van Heel said, there’s no need to memorize any recipe or method. The National Center for Home Food Preservation (NCHFP) has all the up-to-date information on how to can just about everything, she said.

Van Heel also noted that even though a family may have a canning recipe or method that they’ve been using for years and years, it still doesn’t mean it’s the safest way to preserve their food.

One of the most common items people want to can are their own salsa recipes, Van Heel said. However, she recommends against using your own recipe and only using the research-based recipes available on the NCHFP website at nchfp.uga.edu. Most salsa recipes are not acidic enough to be safely preserved using water bath canning, and there are no tested recipes for pressure canning salsas, she said.

There are several different methods of canning, including water bath processing, pressure canning and steam canning. For water bath processing, Van Heel said, just about any stockpot can be used, but it should have some type of rack on the bottom to allow water to heat underneath the glass jars. The jars should also be completely submerged, with at least an inch of water above the lid of the jar.

Pressure canners and steam canners can be found at most hardware stores or online. Many home pressure cookers, like an InstantPot, also work as pressure canners. However, the user should check with the manufacturer before attempting to use the appliance for canning to make sure it is compatible.

Iowa State University Extension and Outreach has an AnswerLine staffed with experts for help with questions about canning. They are available by phone at 800-262-3804 or 515-296-5883, Monday through Friday from 9 a.m to noon and 1 p.m. to 4 p.m. Questions can also be sent via email to [email protected].

Free fact sheets on canning everything from tomatoes and other vegetables, to fruits and jams, to pickles and meats, can be found on the ISU Extension website at https://store.extension.iastate.edu/product/16631.

Do’s

• Research if the food you want to preserve can be safely canned – is it acidic enough or can it be heated hot enough? According to Van Heel, the NCHFP says acid levels in foods being canned using water baths need to be below 4.6 to prevent the growth of botulism and other bacteria. Certain foods are known to have sufficient acid levels, but if you’re concerned, a food-grade pH-meter can be used to verify acid levels.

• Use research-based recipes from the National Center for Home Food Preservation (nchfp.uga.edu). Not every recipe is safe to can. Recipes with different ingredients also need to take into account the heat processing time needed for each ingredient.

• Know what kind of canner (water bath, pressure, steam) is right for the food being canned.

• Know what size jar is needed for the recipe. Not all jar sizes are created equal. For items like jams and jellies, use a smaller jar, Van Heel said.

• Gather all ingredients and supplies needed before you start. You want to make sure you have supplies like a jar-lifter, a scale, a canning funnel, a timer and more on hand to hep with the process.

• Let jars sit undisturbed for 12-24 hours after processing. This helps ensure a good seal on the lid. After 12-24 hours, check to see if the jar is sealed properly. The lid should stay on the jar even when the ring band is removed. Van Heel also recommends storing jars of canned foods without the ring bands because moisture can get trapped between the band and the jar and cause rusting that can make it difficult or impossible to open the jar months later. If the lid is sealed properly, she said, the band isn’t needed. However, if you’re going to be moving the jars around for any reason, she suggests putting the bands back on temporarily to help keep the lids in place.

Don’ts

• Don’t use just any recipe – make sure the recipe is acidic enough for the water bath or that the product can be canned using a pressure canner. Van Heel recommends using only tested, research-based recipes, which can be found online.

• Don’t try to double a recipe. Doubling a recipe or using the wrong sized jars can cause changes to the processing time for products.

• Don’t leave too much or too little head space (space between the top of the product and the lid). Too much space leaves room for air that can cause the jar to not seal properly, Van Heel said. Too little space can cause the product inside to bubble over and not seal at all.

• Don’t use the wrong method to process the canning jars. Low-acidic foods should not go in a water bath, but should be pressure canned.

For more information: www.extension.iastate.edu/humansciences/preserve-taste-summer

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