Pickling is a preservation method that submerges food, usually vegetables or fruit, in a liquid acidic enough to stop the bacteria, yeasts, and molds that cause spoilage. There are two main routes: quick pickling adds vinegar directly to the brine for an almost-instant tang, while fermentation pickling (lacto-fermentation) relies only on salt water, in which naturally occurring bacteria produce the acid over days or weeks - this is how classic dill pickles, sauerkraut, and kimchi are made. The technique is ancient and appears across nearly every cuisine, most often as a condiment or side dish that adds a tangy or sour contrast to richer food. Pickled foods can also carry probiotic benefits when made by fermentation, since vinegar pickling does not produce live cultures.