During the summer, I usually go a little overboard at the farmers market in our town. But who can blame me? The sight of wooden crates overflowing with juicy plums and succulent cherries can make any sane person weak in the knees. And let’s not forget to mention the basil plants loosely piled high on a folding table or the bottomless barrels of sweet corn. Or the heirloom tomatoes. Or the yellow zucchini. Or the spaghetti squash. I usually arrive just as the last stand is setting up, with my four oversized yet empty canvas bags scratching my shoulders, begging to be filled. After what seems like an eternity but only minutes in reality, and with my bags brimming with the summer’s bounty, my husband shakes his head reproachfully and says, “How are we going to eat all of that?”
I’ve tried to make my farmers market purchases last well past the summer months—and sometimes through to the following summer—by freezing each week’s leftovers. Recently, it came to my attention that many people try to preserve their food by canning it and that I should try it, too.
Canning Gets Hip
Canning is a method of preserving food via heat processing in a sealed container. Also known as bottling or tinning, it can be traced to the days of Napoleon, when he sought a way to preserve food and transport it to his hungry troops hundred of miles away. Though popular for decades, it’s not your grandma’s pastime anymore. Today, there are dozens of books, all written and published in the last ten years, that have updated the recipes to suit the modern day home cook—smaller portions, better ingredients. And home cooks preserve their food via canning for different reasons, ranging from economical (e.g., canning my bulk purchases saves money) to socio-political (e.g., canning my own food keeps me independent of the agro-business cycle).
Now back to grandma. So, sweet granny sees that you are interested in canning and proudly presents you with her recipes and tips on canning. But in ye olden times, people canned their food using the open kettle method in which the food is cooked in an ordinary pot or kettle using brines or sugar syrups, then packed into hot jars, immediately sealed with a lid, and that’s it. But beware. The temperatures obtained in open kettle canning are not high enough to destroy all spoilage and infectious organisms that may be in the food. Also, when the food is transferred into the jars, it is exposed to the open air—which can re-contaminate the food. So do yourself a favor when grandma gives you her canning recipes: thank her profusely, shower her with your attention, and then, when she’s not looking, toss them in the trash.
The Proven Methods
The only two methods of canning that successfully preserve food and are recommended by the USDA—as well as every other authority on food safety, from major universities to non-profit organizations—are the boiling water method (using a water bath canner) and the pressure cooker method. This means that all other types of canners and methods of canning, which include solar, microwave, steam, oven, and even canning in the dishwasher, are unacceptable and should be avoided.
When placed in a water bath canner or a pressure cooker canner, the canning jar is exposed to extremely high temperatures that prevent the food from spoiling and kill microorganisms that cause food poisoning. This heating process also drives air from the jar, creating a vacuum seal as the food cools.
According to the National Center for Home Food Preservation, not all foods can be canned the same way. Naturally acidic foods, like most fruits, can be processed using the boiling water method. Foods that contain low or no acid must be processed in much higher temperatures, which can be achieved in a pressure cooker canner. Botulism-producing bacteria are more likely to be present in low or no acid foods, and produce spores that can survive in boiling water, but are destroyed at 240º F or higher. Or you can alter the acidity of your food by adding vinegar, lemon juice, or any other type of citric acid.
Another big question for canners is whether the food can be packed in raw. Most fruits can be packed into the canning jars raw, with the exception of apples, pears, melons, and rhubarb, which must be packed into the jars hot. All vegetables must be hot prior to packing, though tomatoes are the one exception (but then again, tomatoes aren’t really vegetables, are they?)
So, now that you are armed with a little bit of history and background on the approved methods of canning, where to begin?
In addition to buying a much needed “how to” guide, like the Complete Guide to Home Canning and Preserving, a novice canner will need to buy canning equipment. A quick search on Amazon.com shows that a full water bath canning kit (water bath canner, jars, lids, rack, lifter, wand, funnel, and instruction book) can cost under $50.00. A pressure cooker canner alone (no jars, lids, or rack) runs about $100. Canning jars, like the Ball Mason Jar, can be reused several times and cost approximately $10 for a dozen sixteen-ounce jars. You can also buy reusable rubber lined jar lids, which cost approximately $5 for twenty lids.
And if you’re like me, go to your local farmers market and buy that bushel of pears, eat half of it before the week is through, and can the rest … because you can!