I attended a half-day canning workshop on July 30 hosted by the Mississippi State University Extension Service office here in Oxford. (Sorry, Ole Miss, but MSU has the statewide rights to that program.)
Lafayette County Extension Service agent Patty Hudek led workshop participants through a how-to regarding canning, pickling and preserving that included videos, a PowerPoint presentation, and hands-on demonstration. The workshop focused on safety techniques and practices.
Several participants admitted to suffering from “fear of canning” because of high school biology classes featuring Clostridium Botulinum, the deadly contaminant ready to lurk in improperly canned foods. Despite that fear, some of us previously had attempted canning, and arrived with questions about past failures.
What we learned is that modern food canning is much more stringent than what our mothers and grannies practiced in the good ol’ days. It’s no wonder persons who shall remain nameless have been known to poison our families, however unwittingly.
We also learned that even the most carefully prepared jars might fail to seal properly due to variable factors such as the humidity, ambient temperature, bubbles remaining in the jarred product, and imperfect sealant on the jar lid. Of the nine jars of tomatoes our workshop team canned last week, one jar failed to seal for no obvious reason.
Occasionally, during processing, the cook recognizes that a jar is going to fail. It’s usually better not to attempt reprocessing the jar because the additional heat will alter the jar contents. But don’t toss it. Refrigerate the unsealed jar and use it like any other leftovers.
Follow my guidelines below for sure-fire success. I hope to see everybody at the City Market and Mid-Town Farmers Market next week!
Rule Number One: Never use compromised products for canning. This means the jars, the lids and the food itself.
Let me be more explicit.
Forget reusing old jar lids. Forget using leftover jars that once contained store-bought spaghetti sauce or jelly or pickles. Forget using paraffin to seal the jelly. Forget “saving” bruised, deteriorated samples of fruits or veggies to use in canning. That old adage holds true in canning: Garbage in. Garbage out!
Rule Number Two: Always use proper canning jars, new jar lids, and undamaged screw bands for the lids, and be sure to thoroughly wash and sterilize them before and after each use. Proper sterilization required jars to be upright completely covered by at least one inch in boiling water for 10 minutes. NOTE: If properly washed and cleaned, jars might not need pre-sterilization when making jams and jellies, because the hot water bath process requires at least 10 minutes.
Rule Number Three: There are two safe ways of canning — the Boiling Water Bath method, and the Pressure Canner method. Think of both processes as homemade pasteurization.
The boiling water bath is used for high acid foods (pH 4.6 or below) such as fruits, tomatoes, pickles, jams, jellies and preserves. The water bath temperature is at 212˚F in altitudes below 1,000 feet.
The pressure canner method must be used for low-acid foods (pH greater than 4.6) such as meats, poultry, seafood and lower-acidity vegetables — even green beans, despite Grandmother’s insistence that the hot water bath was adequate. The pressure canning method calls for temperatures at or above 240˚F.
Rule Number Four: The amount of unfilled space left between the product and the top of the jar makes a world of difference in whether or not the jar will seal properly. Called “headspace,” oxygen is removed from this free space during the sealing process. The correct headspace for jellies and jams is a quarter-inch. For high-acid contents such as tomatoes, it’s a half-inch.
Rule Number Five: Follow recipe instructions, and do not make substitutions if they call for canning/pickling salt or additional acid such as bottled lemon juice or citric acid. When a pickling recipe calls for vinegar, ALWAYS use commercially prepared vinegar with known acidity. When a recipe calls for citric acid or bottled lemon juice, fresh or frozen may not be used.
Rule Number Six: There are prescribed lengths of time for specific types of products to undergo the hot water bath process and the pressure canning process. The altitude makes a difference, just as it does when baking.
Follow recipe instructions, or check with your local home extension service to clarify the processing timing. The U.S. Department of Agriculture and all state home extension services have that information.
Rule Number Seven: Do not over-tighten the lid when prepping the jar for processing. After processing, do not attempt to re-tighten the jar lid. Place processed jars on a towel to absorb the heat, and allow them to sit out for 12-24 hours. Any jar lids that can be pressed in the center after that time will have failed to seal.
Materials needed for canning jams, jellies, preserves and pickles:
Jar lifter Lid lifter (has a magnet on the tip)
Bubble remover and headspace tool (a plastic knife will work fine)
Boiling water bath canner, which contains a lift-out wire rack (or use a large metal pot with tight-fitting lid and a wire rack)
Before starting a canning project, gather all the materials needed. Make sure you have all the ingredients needed for the recipes. Wash with dishwashing detergent, and rinse everything to be used in the preparation, including: The canning-prep materials, ladles and spoons that will be used, and all canning jars, lids and screw lids. Drain well, with jars upside down on a rack.
To make foods using the hot water bath processing method, fill water bath canner with water and bring to a simmer. Also fill a large pot or turkey roaster with water and bring to a low simmer. Lower the heat but keep water warm in the large pot and add the sealable jar lids and jars to keep them warm. The Home Extension Service recommends keeping an additional pan or kettle of water hot for adding to the canner as needed.
When ready to fill the jars, remove with jar lifter and wipe dry with clean paper towels. Fill the jars to appropriate headspace. Use lid lifter to remove warmed sealable lids from the water and position on the jar. Press down in the center to stabilize the lid position, and tighten screw band. DO NOT OVER-TIGHTEN.
Using the jar lifter, grip each jar in upright position, and place in the hot water bath. Do not crowd the jars, which should not be touching. Water should cover the jars by about 2 inches. Process by simmering, covered, for the designated length of time. Remove each jar, lifting vertically, to a towel-covered flat surface. Allow to sit undisturbed for 12-24 hours. Do not re-tighten the lids during this time or you might break the still-fragile seal.
To test for proper seal, press down in the center of the jar lid. If it pops, the seal is broken. If it is tight, the seal is good. Store in a cool, dark space that does not have temperature fluctuations — an indoors closet such as the kitchen pantry.
The Home Extension Service recommends removing the jar lid screw bands during storage because they can rust over time and compromise the integrity of the jar lid seal where the screw band touches the edges of the jar lid.
For more information, contact the MSU Extension Service.
The MSU Extension Service provides research-based information, educational programs and technology transfer focused on issues and needs of the people of Mississippi, enabling them to make informed decisions about their economic, social and cultural well-being. The Lafayette, Marshall and Yalobusha County MSU Extension Service agents frequently collaborate on programs for our region.
NOTE: the SEC reigns nationally in the home canning arena. The National Center for Home Food Preservation is housed at the University of Georgia, which also has a statewide extension service, like most states.
Here are some other useful links about canning, preserving and pickling:
Laurie Triplette is a writer, historian, and accredited appraiser of fine arts, dedicated to preserving Southern culture and foodways. Author of the award-winning community family cookbook GIMME SOME SUGAR, DARLIN’, and editor of ZEBRA TALES (Tailgating Recipes from the Ladies of the NFLRA), Triplette is a member of the Association of Food Journalists (AFJ),Southern Foodways Alliance (SFA) and the Southern Food and Beverage Museum (SOFAB). Check out the GIMME SOME SUGAR, DARLIN’ web site: www.tripleheartpress.com and follow Laurie’s food adventures on Facebook and Twitter (@LaurieTriplette).