Canning jars and safety

Do you need to pre-sterilize jars before home canning?

Food preservation of fruits and vegetables is in full swing. As you are canning the summer harvest, remember that it is a good idea to take a few minutes to inspect your canning jars and understand their importance in the canning process. Are you using jars that you have recycled over the years, or are you purchasing brand new jars for use this summer? Even when you purchase new jars in a box covered in plastic wrap, those jars are still not in a sterile environment. In addition to contamination by microorganisms that cannot be seen, packaged jars may accumulate dust, small bits of debris and even chips of glass in the case of breakage.

Michigan State University Extension reminds you that no matter what jar you are using, brand new or recycled from past use; you should always thoroughly wash jars just prior to filling them with your fruits or vegetables. Wash jars in a dishwasher or by hand, using detergent and rinsing well. Clean jars should then be kept warm prior to filling. You can leave them in the closed dishwasher after the cycle, place them in your canner as it is preheating, or create a separate water bath to keep jars clean and warm. As you are washing jars, it is a good time to inspect them for any cracks or chips. Discard any jars that have been chipped or cracked as they won’t seal properly.

The National Center for Home Food Preservation shares that in order to actually sterilize jars; they need to be covered by boiling water for 10 minutes. When a process time is 10 minutes or more, the jars will be sterilized during processing in the canner. When process times are 10 minutes or more, pre-sterilization of jars is not needed.

To pre-sterilize jars, place the clean jars right-side-up on a rack in a canner and fill the jars and canner with water to one-inch above the tops of the jars. Bring the water to a boil for 10 minutes at altitudes less than 1,000 feet elevation. When you are ready to fill the jars, remove the jars one at a time, emptying the water from them back into the canner. This will keep the hot water in the canner for processing filled jars.

Staying up-to-date on home food preservation techniques and recommendations will allow you to preserve a safe and great tasting product for your family to enjoy all winter long.

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