Pickling is the preservation of food in an acidic solution, typically vinegar or a lactic acid brine. The acid environment prevents the growth of spoilage microorganisms and gives pickled foods their characteristic sour flavor. Pickling can be divided into two categories: fermented pickles, which develop acidity through natural [[Fermentation]], and fresh-pack pickles, which are preserved with vinegar.
Fermented pickles are made by submerging cucumbers or other vegetables in a salt brine and allowing lactic acid bacteria to produce acid over several weeks. The brine concentration is 5 to 8 percent salt by weight. The fermentation takes 3 to 6 weeks at 18 to 22 degrees Celsius (65 to 72 degrees Fahrenheit). The resulting pickles have a complex, tangy flavor from the mixed bacterial fermentation. Dill, garlic, peppercorns, and bay leaves are added for flavor.
Fresh-pack (quick) pickles are made by heating vegetables with a vinegar solution and processing in a water bath canner. The vinegar solution is typically 50 percent vinegar and 50 percent water, with salt and sugar added. The acidity of the final product must be high enough to prevent botulism: the vinegar must be at least 5 percent acetic acid. Fresh-pack pickles are ready to eat immediately but improve in flavor after 2 to 4 weeks.
Dill pickles are the most common pickle type, made with dill weed and garlic. Sweet pickles include sugar in the brine. Bread and butter pickles are sweet, thinly sliced pickles with turmeric for color. Pickled beets, pickled eggs, pickled peppers, and pickled green beans are also common. Pickled vegetables are processed in a water bath canner for shelf stability.
Pickling requires a large non-reactive pot (stainless steel, enamel, or glass), a [[Canning]] jar set, and a water bath canner. Aluminum and copper pots react with the acid and should not be used. The canning jars are sterilized before use. Weights are used to keep vegetables submerged in fermented pickles. Airlocks prevent oxygen from entering the fermentation vessel.