Fall is here in all its glory. Days are shorter and cooler. On a brisk autumn afternoon, we can preserve memories of warm summer days. But to safely prolong all that sunshine by preserving our favourite fruits and vegetables, certain basic rules apply. The air we breathe and all foods in their natural state contain microorganisms like molds, yeast, bacteria as well as enzymes. If these microorganisms are not controlled, the food will spoil. Using proper preserving techniques will control the growth of decay microorganisms, allowing us to keep food beyond its normal storage period. Safe food preservation requires heat processing according to tested uptodate methods.
Use the Right Jars
To do this, you must first use glass mason jars that can be vacuum sealed with their twopiece metal SNAP lids. The filled jars must be heated in a large pot or canner to the temperature specified for the food being processed. To destroy spoilage microorganisms, inactivate enzymes and vent air from the jars, the required temperature must be maintained throughout the processing time specified in the recipe. Also follow the instructions for cooling the jars to make sure the SNAP lids form a strong vacuum seal.
Creating a Vacuum Seal
As the filled jars heat, the content and the air inside the jar expand, and internal pressure changes take place. These changes allow gasses or air to be expelled from the jar. After processing, the surrounding atmospheric pressure is greater than the jar’s inner pressure as a result of air expulsion. This pressure difference causes the lid to be pulled down onto the jar as it cools, forming a vacuum seal. The resulting seal prevents microorganisms and air from entering and contaminating the food.
Home Preserving Basics
Use only the best quality ingredients and, if possible, fresh Quebec produce picked at its peak of ripeness. Heat process all home-preserved foods. Process high acid foods (jams, jelly, pickles, relish, chutney and condiments, fruits and fruit juices, tomatoes) in a boiling water canner or large pot of boiling water. Process low acid food (vegetables, meats, seafood, poultry, prepared foods such as soups and sauces, tomatoes with vegetables or meat) in a pressure canner. Use only uptodate tested recipes that include the appropriate heat processing method for the type of food being preserved and specify the proper processing time for the type of food and mason jar size. Also make sure your preserve recipes come from a reputable source and that they indicate the recommended headspace for the type of food and jar size. Follow the manufacturer’s instructions regarding the method for preparing the jars and SNAP lids.
- Heat the mason jars by setting them on the canner/pot’s rack. Do not reheat the jars in the oven (the dry heat could cause thermal shock which would shatter the jar).
- Set the screw bands aside; immerse the SNAP lids in very hot NOT boiling water (82 ºC/180 ºF).
- Ladle prepared hot food into hot jars, leaving the proper head space. The jar could break if it is cold when you fill it with hot food.
- Remove air bubbles by sliding a non-metallic utensil between the jar and food or by pressing slightly on the food.
- Wipe the rim and the thread of the jar with a clean damp cloth to remove any spills.
- Center a SNAP lid on each jar and turn screw bands evenly and firmly just until resistance is met—finger tip tight. Do not over tighten.
Once the processing is complete, remove the jars from the canner/pot and let stand upright on a towel in a draft-free place.
DO NOT TIGHTEN the screw bands or check the seal while the jars are still hot. Cool jars undisturbed for 24 hours.
After cooling is completed, check jar seals. Properly sealed jars will have a depression in the top and will be stuck to the jar rim. (Reprocess or refrigerate any unsealed jars.)
Once the jars are sealed, remove, wash and dry the screw bands; wash and dry the exterior of the jars. Store screw bands separately or replace loosely on the jars.
Need more information ?
If necessary, don’t hesitate to consult recipe books or other Internet sites on this subject. We have drawn most of the above information on the mason jar site at www.homecanning.com. You are now ready to savour your succulent preserves, pickles and jams for many months to come.