Pickling

Pickling is the process of preserving or extending the shelf life of food by either anaerobic fermentation in brine or immersion in vinegar. The pickling procedure typically affects the food's texture and flavor. The resulting food is called a pickle, or, if named, the name is prefaced with the word "pickled". Foods that are pickled include vegetables, fruits, mushrooms, meats, fish, dairy and eggs.

Pickling solutions are typically highly acidic, with a pH of 4.6 or lower, and high in salt, preventing enzymes from working and micro-organisms from multiplying. Pickling can preserve perishable foods for months, or in some cases years. Antimicrobial herbs and spices, such as mustard seed, garlic, cinnamon or cloves, are often added. If the food contains sufficient moisture, a pickling brine may be produced simply by adding dry salt. For example, sauerkraut and Korean kimchi are produced by salting the vegetables to draw out excess water. Natural fermentation at room temperature, by lactic acid bacteria, produces the required acidity. Other pickles are made by placing vegetables in vinegar. Unlike the canning process, pickling (which includes fermentation) does not require that the food be completely sterile. The acidity or salinity of the solution, the temperature of fermentation, and the exclusion of oxygen determine which microorganisms dominate, and determine the flavor of the end product.

When both salt concentration and temperature are low, Leuconostoc mesenteroides dominates, producing a mix of acids, alcohol, and aroma compounds. At higher temperatures Lactobacillus plantarum dominates, which produces primarily lactic acid. Many pickles start with Leuconostoc, and change to Lactobacillus with higher acidity.

Pickling with vinegar likely originated in ancient Mesopotamia around 2400 BCE. There is archaeological evidence of cucumbers being pickled in the Tigris Valley in 2030 BCE. Pickling vegetables in vinegar continued developing in the Middle East region before spreading to the Maghreb, Sicily, and Spain. From Spain, it spread to the Americas. Fermented salt pickling reportedly originated in China.

There is sufficient archaeological evidence that pickling was also practiced in Ancient Egypt, Ancient Greece, and throughout the Roman Empire. The Ancient Egyptian pharaoh Cleopatra was known to credit the pickles in her diet for her good health and beauty. Roman emperors were also known to make pickles a part of their troops' diets, with the belief it would make them stronger and more fit for battle.

Pickling was used as a way to preserve food for out-of-season use and for long journeys, especially by sea. Salt pork and salt beef were common staples for sailors before the days of steam engines. Although the process was invented to preserve foods, pickles are also made and eaten because people enjoy the resulting flavors. Pickling may also improve the nutritional value of food by introducing B vitamins produced by bacteria.

The English term "pickle" first appears around 1400 CE. It originates from the Middle English pikel, a spicy sauce served with meat or fish, borrowed from Middle Dutch or Middle Low German pekel ("brine") but later referred to preserving in brine or vinegar.

South Asia has a large variety of pickles (known as achar (अचार, اچار) in Nepali, Assamese, Bengali, Hindi (अचार), Punjabi, Gujarati, Urdu (اچار) uppinakaayi in Kannada, lonacha (लोणचं) in Marathi, uppilittathu or achar in Malayalam, oorukai in Tamil, pacchadi (పచ్చడి) or ooragaya (ఊరగాయ) in Telugu, which are mainly made from varieties of mango, lemon, lime, gongura (a sour leafy shrub), tamarind, Indian gooseberry (amla), and chilli. Vegetables such as eggplant, carrots, cauliflower, tomato, bitter gourd, green tamarind, ginger, garlic, onion, and citron are also occasionally used. These fruits and vegetables are mixed with ingredients such as salt, spices, and vegetable oils. The pickling process is completed by placing filled jars in the sun to mature. The sun's heat destroys moulds and microbes which could spoil the pickles.