Pickling

Pickling is a method used to preserve food or extend its shelf life.

This process works through either immersion in vinegar or anaerobic fermentation in brine. The resulting food is called a pickle, or is described as "pickled" when referring to a specific item. People use pickling to preserve a wide variety of items, including vegetables, fruits, mushrooms, meats, fish, dairy, and eggs. This technique changes both the texture and the flavor of the original food. Pickling can keep perishable foods edible for many months or even years.

The science of pickling relies on controlling the environment to prevent spoilage. Pickling solutions are typically highly acidic, maintaining a pH of 4.6 or lower. They are also high in salt content. These conditions prevent enzymes from working and stop micro-organisms from multiplying. If food contains enough moisture, a pickling brine can be made simply by adding dry salt. This method is used to produce foods like sauerkraut, kimchi, and sour cabbage. In these cases, salt draws out excess water to start the process.

Natural fermentation occurs at room temperature through the action of lactic acid bacteria. This biological process produces the necessary acidity for preservation. The specific flavor and type of microorganism that dominates depend on several factors. These include the acidity or salinity of the solution, the temperature of fermentation, and the exclusion of oxygen. When both temperature and salt concentration are low, a bacterium called Leuconostoc mesenteroides dominates. This produces a mix of alcohol, aroma compounds, and acids. At higher temperatures, Lactobacillus plantarum becomes dominant and produces primarily lactic acid. Many pickles begin with Leuconostoc and transition to Lactobacillus as acidity increases.

Pickling has a very long history spanning thousands of years. Vinegar-based pickling likely began in ancient Mesopotamia and Persia around 2400 BCE. Archaeological evidence shows that cucumbers were being pickled in the Tigris Valley by 2030 BCE. Fermentation using salt is reported to have originated in China. Archaeological evidence also confirms pickling was practiced in Ancient Greece, Ancient Egypt, and the Roman Empire. The Egyptian pharaoh Cleopatra famously credited pickles for her beauty and health. Roman emperors also included pickles in the diets of their troops to help them stay fit for battle.

During the Age of Exploration, pickling became essential for long journeys at sea. Before steam engines were common, sailors relied on staples like salt beef and salt pork. Pickling allowed people to eat seasonal foods even when they were out of season. Beyond preservation, people enjoy pickles for their unique flavors. The process can also improve nutritional value by introducing B vitamins produced by bacteria. The English word "pickle" first appeared around 1400 CE. It comes from the Middle English "pikel," which was a spicy sauce for meat or fish.

Different regions of the world have developed unique styles of pickling. In South Asia, pickles are known by many names, such as achar in Hindi or Urdu.

These are often made from mango, lemon, lime, or chili mixed with salt, spices, and vegetable oils. In many South Asian traditions, jars are placed in the sun to mature. The heat from the sun destroys microbes and molds that could spoil the food. In Sri Lanka, a traditional date and shallot pickle called achcharu is prepared in clay pots.

In Southeast Asia, Malaysian pickles known as jeruk are often made in brine using starchy water.

East Asian cultures also have deep pickling traditions. In Japan, pickled foods are called tsukemono.

One common method is Shio-zuke, which means salt pickles. Another version is ichiyazuke, an overnight pickle that uses salt to speed up the process. Umeboshi is a type of salt-preserved Japanese plum that is dried in the sunlight for several days. In Korea, kimchi is a famous side dish made from napa cabbage, radish, and red chili powder.

In Burma, the pickling of tea leaves creates lahpet, a dish with great social and cultural importance.

In Europe, pickling styles vary by country and region. In Hungary, pickles like sauerkraut and csalamádé are common parts of the main meal.

A unique Hungarian seasonal pickle is leavened cucumber, which is made by putting cucumbers, spices, and bread slices in salt water. The yeast from the bread helps ferment the cucumbers in the sunlight. In the West Asia region, pickles are often called torshi, turşu, or mekhallel.

These often consist of a mix of cucumbers, turnips, onions, and carrots. These diverse traditions show how pickling connects food preservation to local culture and flavor.