Wednesday, March 2, 2011

PRESSURE CANNING

Pressure canning is an economical method of preserving low acid foods and the only method recommended as safe by the United States Department of Agriculture (USDA) for low-acid foods such as vegetables, some fruits, meats, fish and seafood.  A temperature of 240 F must be reached and maintained for a specified amount of time to kill harmful bacteria. This temperature can be reached only by creating steam under pressure.


Pressure canners can be relatively expensive, but if properly cared for will last years. If you plant a good-sized garden or can get lots of produce cheaply, it is definitely worth having one in your pantry. If your family is small and canning is something you probably will not do that often, freezing and/or canning using a Hot-Water Bath is probably good enough.


Hot Water Baths, aka Boiling Water Baths, are suitable only for canning strong acid foods like tomatoes – and for finishing pickles, relishes, jams, jellies, chutneys, conserves, vinegary preserves and the like.


Pressure canners were redesigned in the 1970's. Models made before the 1970's were heavy-walled kettles with clamp-on or turn-on lids. Modern pressure canners are lightweight, thin-walled kettles.


To be considered a pressure canner for preserving food, and not just for cooking under pressure, the USDA recommends that the pressure canner be large enough to hold at least 4 quart-sized jars. Really, in this case, bigger is better.


A tight-fitting lid that holds the ‘controls’ covers the kettle itself. Clamps fasten down the lid. Basically, pressure canner controls are: a pressure gauge, often referred to as the ‘dial’; an open vent to let steam escape; and a safety valve that blows if the pressure becomes unsafe.


Like the hot-water bath canners, the pressure canner will have a removable rack to keep the jars from touching the bottom of the canner or each other, and/or a wire basket that lets you lift all your jars out at one time.


Food scientists have determined that 10 pounds in the sea-level zone (240 F/116 C) as the safest and most effective pressure to use for low-acid foods. Depending on your location across the country, that amount will be variable, make sure to read instructions for putting your food by carefully and adjust the pressure accordingly.


Do not be intimidated by pressure canning. Your new pressure canner, and I do recommend purchasing a new canner - not a used one, will come with instructions. Take the time to read them through carefully and you will realize that operation is not as difficult as you may think.


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3 comments:

  1. My mom canned tomatoes, peaches, applesauce, and pickles using a hot water bath canner. Sometimes I think about canning, although we're so fortunate to have access to most fruits and vegetables year-round, and there's just the three of us (and Garrett eats no vegetables and hardly any fruit). And the the possibility of botulism or a pressure canner explosion terrifies me a little, frankly. I tend to freeze things if I want to keep them - and Alan insists we go through the freezer on a regular basis.

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  2. Well freezing is a great option. Lots of people are afraid of getting sick, but if you open up something and it smells awful, feed it to the pigs, throw it in the compost, or just trash it. I know you are fearless. Maybe someday when you get bored with knitting and need a new outlet? You never know!

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  3. Dear Elizabeth, I have never ventured into pressure canning, though the possibilities are probably endless in its use. I would like to thank you for stopping by my blog. In answer to your question about the choice of lentils, I use the dried lentils that you purchase in the grocery store. Blessings, Catherine

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