I found a treasure trove of my grandmother’s canning recipes and am eager to use them. They use some interesting techniques, such as canning in the oven and flipping the hot, filled jars instead of using a water bath canner. Are there reasons why I shouldn’t use these canning recipes?
When it comes to safe methods for canning foods, this is one instance in which modern advice is better than old-time techniques. The best way to be sure your home-canned foods are safe is to use only recipes that you know have been tested and verified safe by food scientists, who have learned a lot about food preservation over the years.
Two top publications are the most recent U.S. Department of Agriculture publication, So Easy to Preserve (fifth edition), which includes 184 tested recipes along with complete details for safe home canning, and the Ball Complete Book of Home Preserving. Another excellent source is Fresh Preserving, a website hosted by the Ball Corp., which manufactures jars and lids for home canning. This website includes more than 200 tested canning recipes.
Safe home canning depends on applying the proper amount of heat to kill microbes, and the amount of heat required depends in part on how the food is prepared, including what sizes the vegetables or fruits are cut into. Tested recipes have been monitored to confirm how much time (and for non-acid foods, how much pressure) is required for the heat to fully penetrate the pieces of food in whatever size jar is being used. Older hand-me-down recipes may not have ever been tested — there’s just no way to know. Precise acidity and salt/sugar levels are also important factors, which is further reason to always use recipes that have been tested by food scientists.
Older canning recipes sometimes call for unorthodox practices, such as flipping filled hot jars upside down to allow them to seal, or canning by setting the jars in an oven or out in the sun. Those methods aren’t acceptable for several reasons, says food scientist Karen Blakeslee of Kansas State University. While alternative methods may cause the jar to seal, Blakeslee says, they do not guarantee that the food inside has reached the proper temperature for storage.
You can change some things in tested canning recipes, though. “You can typically change spicing, or change the variety of peppers in salsas as long as you use the same amount,” Blakeslee says.
When canning fruits, you can reduce or eliminate sugar and can the fruit in water or fruit juice. Artificial sweeteners are not appropriate, however, Blakeslee says — they’re not heat-stable and will sometimes make your food bitter. Although the risks are probably low if you were to use your grandmother’s recipes, chances are you can find similar tested recipes from the previously mentioned sources.
— Robin Mather, Senior Associate Editor
Robin Mather is a senior associate editor at MOTHER EARTH NEWS and the author of The Feast Nearby, a collection of essays and recipes from her year of eating locally on $40 a week. In her spare time, she is a hand-spinner, knitter, weaver, homebrewer, cheese maker and avid cook who cures her own bacon. Find her on Google+.
Photo by Tim Nauman Photography