Among the shifts in home life brought about by the COVID-19 pandemic is a significant surge in home canning. This is not surprising, given the gardening boom, more time spent at home, and the economic downturn. Unfortunately, this has created some shortages that are not only frustrating for home preservers but can create serious safety risks.
Equipment Supply Shortage
Most notably, there is a shortage of canning lids. If you are not familiar with the home canning process, home canning relies on a two-piece lid system. The ‘rings’ that screw on jars can be reused, but the flat round lids must be new. Lids cannot be reused because the exposure to the high heat and pressure from processing causes changes to the sealant. Additionally, over time the sealant can become less pliable. Lids should be used within five years of manufacture. After that time, the strength of the seal may be compromised.
In some areas, vinegar has also been difficult to find. Any vinegar used for canning should be at least 5% acidity. If a specific type of vinegar is not given in a recipe, white or cider vinegar may be used.
For boiling-water canning of acidic foods, like salsa or pickles, any large pot can be used as long as you have a rack that fits the bottom. These canners will also need to have room for 1 to 2 inches of water above the jars.
But for foods that are low in acid, like green beans or carrots, a pressure canner must be used. This is required because Clostridium botulium bacteria are able to form spores that can withstand very high temperatures, so the food in jars must reach 240°F in order to inactivate the spores. At low elevations, boiling water only reaches 212°F and in Colorado, it boils at even lower temperatures, so pressure is needed to achieve a sufficiently high processing temperature. This is a critical point because home-canned vegetables are the most common cause of botulism outbreaks in the U.S. and the use of acid and heat are our best tools for ensuring harmful pathogens are destroyed.
There is also a shortage of pressure canners this year. People are finding pressure canners at garage sales, thrift stores or from family members. Before using these canners check to see if gasket and over-pressure plug need replaced. To ensure pressure canners will work safely and properly, the lid of the canner and the pressure gauge should be inspected and tested yearly. Most Extension offices across Colorado (and the U.S.) provide canner lid inspection and testing services. Contact your local Extension office for more information.
Lack of Canning Experience
Home food preservation is an extremely useful and satisfying skill but there is a wide array of information that is needed to ensure the quality and safety of the final product. Several points are especially important when canning at home:
- Colorado’s elevation impacts processing so it is important to know your elevation and adjust canning recipes accurately. Most recipes for home canned foods will require adjustments to time or pressure.
- Tested recipes must be used because they have been verified to meet temperature requirements within that particular food mixture. Tested recipes are available from CSU Extension’s app Preserve Smart, the National Center for Home Food Preservation, or the Ball Blue Book.
- Foods such as tomatoes and salsa require the addition of acid for safety.
- Pressure canners must be able to hold 4 quart jars and be adjustable to up to 15 pounds of pressure.
- Check to make sure your stove-top is suitable for handling the weight of the canning equipment and that electric elements will stay on constantly.
- Before tasting or serving, boil all home-canned, low-acid vegetables 10 minutes plus one minute for 1,000 feet of elevation.
- If supplies cannot be found, freezing fruits or vegetables is a good alternative. With freezing, you can be creative and follow your own recipes.
Family and Consumer Science Extension agents are the best points of contact for home preservation questions so check with your local Extension office for more information. For guidance related to canning methods and recipes, CSU Extension has developed Preserve Smart, which is available as a website or mobile phone app, https://apps.chhs.colostate.edu/preservesmart/
Friday, October 23 is National Canning day. Share with us your favorite thing to can.