Routt County CSU Extension: For canning advice, don’t listen to Grandma or internet bloggers
July 9, 2017
Area Farmers Markets are finally starting to showcase local produce, which means that canning season is just around the corner. For many of us, putting up seasonal produce harkens back to watching grandma in the kitchen with a steaming canner and rows of quart jars cooling on a towel.
If you remember fondly grandma's pickles, Aunt Barbara's stewed tomatoes or a neighbor's salsa, you might be tempted to dig out their old recipe or head to the internet to find a similar recipe. Sometimes these recipes work well, but other times the results can be dangerous, or even deadly. Do you know enough about high altitude food preservation to tell a good canning recipe from a bad one?
Many canning methods from grandma's day have been proven to be unsafe and should be avoided. The mistaken belief that a jar was canned properly if the lid seals was prominent in canning books 30 years ago and can still be found on the internet. We now know that the internal temperature of each jar must reach a critical temperature for a specific amount of time to kill harmful pathogens.
Old-style recipes that instructed people to fill jars with hot ingredients and simply turn jars over to create a sealed lid are not recommended. Inverting jars, heating jars in the oven and even "processing" canned items in a dishwasher will not get the contents of the jar to a safe temperature for long-term storage. Old techniques like sealing jars with paraffin wax have been discredited for years because of the molds and pathogens that can grow under the surface of the wax.
Canning equipment has improved since grandma's day. Newer pressure canners are larger and have safety features to improve the experience.
When buying a pressure canner, at the store or your neighborhood garage sale, make sure that the pressure canner has the newer safety valve feature. Look to see if the canner will accommodate 4-quart jars, which assures that there will be enough space for hot steam to properly heat the jars. Bring your new canner to the Extension Office to test the dial gauge for accuracy.
Canning recipes found on the internet or passed down through the family can be unsafe. Instead, search for tested recipes that include adjustments for altitude. Properly testing recipes for safe canning is an extensive process.
When reliable sources like the National Center for Home Food Preservation, the Ball Blue Book or Extension specialists test recipes, they make each recipe dozens of times. They measure heat penetration and test for microbes in different stages of the canning process. There are plenty of well-tested recipes that would be comparable to grandma's recipe, so call the Extension Office and one of our master food safety advisors can help you find a tested version of a family favorite canning recipe.
If you would like to know more about canning, attend the Basics of Home Canning class at the Extension Office from 10 a.m. to noon Saturday, July 15. Reserve a spot by calling the Extension Office at 970-879-0825. The cost of the class is $10.
Karen Massey is a registered dietitian nutritionist and family and consumer science Extension agent with Colorado State University Extension in Routt County. Call 970-879-0825 or email firstname.lastname@example.org with questions.