Processing jams and jellies
Food preservation of jams and jellies.
The recommended methods for preserving jams and jellies from fresh fruits have evolved from new research on potential health and safety risks. Paraffin or wax is no longer an acceptable method for sealing jars of jams and jellies. Wax paraffin can shrink, crack or have pinholes that allow product to seep out onto the surface, creating mold that can enter into the jam or jelly. The method of inverting (turning the filled jar upside down on its lid) is also not effective in sealing out potential contaminates. If the inversion process does work, the vacuum seals of filled jars still tend to be weaker than those produced in a boiling water canning process.
Even with the high content of sugar in jams and jellies mold can still grow. Research has shown that mold growth on fruit products is not as harmless as believed in the past. There is potential risk of mold poisons from fruit products preserved at home. Michigan State University Extension recommends that all cooked jams and jellies include a boiling water bath canning process for room temperature storage of sealed jars. Presterilized standard canning jars used with self-sealing two piece lids, hot filling of product into jars and processing five minutes in a boiling water canner are recommended for highest quality and to prevent mold growth.
The Cooperative Extension Service at the University of Georgia recommends following these steps in making jam or jelly at home:
- Use only standard canning jars (called Mason jars) with manufacturer’s name printed on the side. Wash in water with detergent and rinse well, either by hand or in the dishwasher. Presterilize the clean jars by submerging in boiling water for 10 minutes. There should be enough water to fill the jars and cover one to two inches above the tops of the jars. Jars can stay in hot water until ready to fill.
- Prepare jam or jelly according to researched recipes, such as the United States Department of Agriculture (USDA) Complete Guide to Home Canning or Ball Blue Book. Boil for the recommended time.
- Empty water from presterilized jars back into the canner. Make sure they are completely drained. Fill jars quickly with hot jelly or jam mixture, leaving a quarter-inch of headspace. Wipe the top of the jars and sealing surface, with clean paper towel to remove jelly, jam or sugar crystals. Place a two-piece lid on the jar and hand tighten the ring.
- Load filled jars one at a time into the canner. Cover the canner and heat until the water boils. Process the jars for five minutes after the water has reached a rapid boil. The water level must remain one to two inches above the tops of the jars during the entire process.
- Remove jars from the canner once the process time is up. Cool jars upright, undisturbed for 12 to 24 hours while lids seal.
- Remove ring bands from sealed jars, place unsealed jars in the refrigerator to be used first. Label and store in a cool, dry place.