For simple food fermentation at home, choose a large, wide-mouth jar made of food-grade plastic, glass or stoneware. Add an anaerobic airlock cap or just use a heavy weight, followed by a regular jar lid once the food ferments.
Mason and Ball jars come in various sizes to accommodate different fermented fruits and vegetables. The basic recipe for fermentation works with an open jar or with a jar that has a reclosable lid, an airlock and a rubber stopper. The airlock draws oxygen from the jar once you close the lid, creating anaerobic conditions for fermentation. Brine that covers the food in the jar also prevents oxygen from reaching the solids and growing mold.
Simple fermentation calls for dicing or chopping the food, sprinkling it with sea salt and tossing it to draw out the natural moisture. Place the fermenting food, completely covered by the brine, in the canning jar. Use a 1-gallon container for every 5 pounds of fresh fruits or vegetables.
Set a heavy weight on the contents of the container, cover the jar with cheesecloth and store it in a dry, moderate temperature for several days -- 70 degrees Fahrenheit is ideal. Lactobacillus microbes break down and ferment the brine-covered food. As long as the food is below brine level, oxygen cannot reach the solids and the process is natural and safe.