With the recent rise in the cost of food, many consumers this summer are planting a garden and wanting to preserve their harvest and enjoy long after summer is over.

Be careful! Improperly canned foods can make you sick and in some cases can be deadly.

One of the biggest mistakes novice canners make is in not pressure canning vegetables, or pressure canning vegetables at a pressure too low for the elevations here in western Colorado. Vegetables are low in acid and must be processed in a pressure canner at the number of pounds needed to achieve 240 degrees F. At sea level the pressure required is only 10 pounds, but at 5,000 feet elevation, the pressure needed is 12.5 pounds. The rule of thumb to determine the amount of pressure needed is to add a half pound of pressure for every 1,000 feet in elevation.

Pressure canning at the correct pounds of pressure for the elevation is absolutely necessary to build enough heat to destroy botulism. Botulism is a serious, often fatal form of food poisoning. Unfortunately foods contaminated with botulism usually have no signs of spoilage and therefore produce no “warning signs” that the food is not safe to be consumed.

Another mistake commonly made when pressure canning is using faulty equipment. Pressure gauges should be calibrated annually to ensure accuracy and canner lids should fit securely with rubber gaskets intact and in good shape. Exhaust vents and safety valves should be kept clean. Steam canners, which are different than pressure canners, should not be used to can with due to the lack of research-based information available on the consistency of the heat produced. Using a small “pressure canner/cooker” that holds less than 4 quart jars should also not be used as they heat up and cool down too quickly to allow for adequate heat penetration.

Other mistakes commonly made when pressure canning include:

• • Taking “short cuts.” Recommended preparation and processing instructions should always be followed.
• • Using jars not specifically designed for home canning. Commercial glass jars with screw-on lids should not be used when canning.
• • Using outdated canning books or instructions. Updated (within the past 10 years) canning books and instructions should be used.
• • Using untested recipes. Canning recipes should always be sought from a reliable source such as your local extension office.

For more information on canning or to have your pressure gauge tested call the Delta County Extension Office at 874-2195.

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