By David Prenatt
When it comes to preserving foods, Cheryl Wahlstrom's advice would be: if you can can can!
Photo by David Prenatt
Cheryl Wahlstrom, a registered dietitian and a certified master food preserver, demonstrates equipment used in canning foods as part of her presentation at Ripley Free Library Thursday evening.
Wahlstrom, a certified master food preserver and a registered dietitian from Jamestown, spoke about various methods of food preservation Thursday evening at Ripley Free Library.
Wahlstrom, also a master gardener, took her training through the Chautauqua County branch of the Cornell Cooperative Extension. Interest in homesteading has increased in recent years, and "the cooperative extension is trying to take the pulse of the people," she said.
Freezing is a good method of preserving because it maintains the freshness and nutrition value of foods, Wahlstrom said. However, the enzymes that cause vegetables to toughen continue to work when frozen. This can be prevented by blanching, that is immersing the vegetable in boiling water for a determined amount of time before freezing, she said.
The great drawback to freezing is that it takes space and energy. Also, a power outage can mean a loss of everything. "This is why canning offers a good alternative," she said.
"The most important thing to remember about canning is that some foods cannot be safely canned in boiling water," Wahlstrom said. All fruits, except figs, are acidic and are therefore safe to process by boiling, but all vegetables, except tomatoes, require a pressure canner for safe processing, she said.
Tomatoes are "borderline" when it comes to safe processing in boiling water, Wahlstrom said, particularly because many recent varieties feature reduced acidic levels. If you are processing tomatoes by boiling, you should add one tablespoon of lemon juice per pint, she said.
"The reason that we are so particular about canning is that doing it wrong can kill you," Wahlstrom said. "Botulism spores are ubiquitous in nature. The trick is just to kill it by acid or temperature."
If it is not killed by proper processing, botulism can form inside of the jar, Wahlstrom said. It is odorless and tasteless. In its later stages it might produce bubbling, but there is enough toxin in the earlier stages to be fatal, she said.
"Fruits are acidic. They are not risky. But if you canning potatoes, carrots, meats, etc., they need a pressure canner." She noted that a regular pressure cooker is not sufficient because it cools down and depressurizes too quickly. Also, she said, there is no approved method for simply packing jars with produce and putting the lid on. "All canned products need processing."
Wahlstrom said if one opens a jar of food and is unsure about its safety, simply dump it in a saucepan and boil it. Boiling kills all botulism spores, she said.
As far as equipment, one should only use jars that are designated for canning. Jars have an average life-span of 15 uses before they become prone to crack, she said. Rings used to hold the lids on can be reused but should always be dried to prevent rust. Canning lids should only be used once, she said.
Before filling the jars, it is good to warm them to prevent temperature shock from hot produce, Wahlstrom said. This can be done by placing the jars in boiling water. Some of this water can be placed in a cake pan in which jars can sit as if in a warmer, she said.
Jars should be filled leaving an appropriate amount of "head space,", that is, 1342535861 room between the product and the lid. When processing, one should add five minutes to the recommended processing time for every 1,000 feet above sea level. Ripley is listed as 1,300 feet above sea level so the minimum canning time for any product would be 10 minutes. "The good news about this is that you don't need to sterilize your jars before filling them. Ten minutes will do it," she said.
Once the jar is processed and placed upon a towel, one should not wipe off the water on top of the lid as this helps the lid to seal properly.
The jars should not be moved for 24 hours, Wahlstrom said. After that time, the ring should be removed and the jar rinsed to remove any food that may have boiled through in processing. The date should be written on the lid and they are ready to store.
Wahlstrom said a good reference for questions about food preservation is the National Center for Home Food Preservation website: www.uga.edu/nchfp .