Lacto-Fermentation is a specific type of fermentation in which lactic acid bacteria convert sugars in food into lactic acid. The term refers to the genus Lactobacillus, not to lactose (milk sugar). Lacto-fermentation is used to preserve vegetables, fruits, and dairy products. The resulting acidic environment (pH 3.5 to 4.5) prevents spoilage and creates a distinctive tangy flavor.
Sauerkraut is made by fermenting shredded cabbage with salt at a ratio of 2 to 3 percent salt by weight of cabbage. The cabbage is massaged with salt until it releases enough liquid to submerge itself. The salted cabbage is packed tightly into a jar or crock, weighted, and fermented at 18 to 22 degrees Celsius (65 to 72 degrees Fahrenheit). Sauerkraut is ready after 2 to 4 weeks at room temperature, developing a more complex flavor with longer fermentation.
Kimchi is a Korean fermented vegetable dish, most commonly made from napa cabbage. The cabbage is salted, rinsed, and mixed with a paste of gochugaru (Korean chili flakes), garlic, ginger, fish sauce, and scallions. The mixture is packed into a jar and fermented at room temperature for 3 to 7 days, then refrigerated. Kimchi contains a wider variety of bacterial strains than sauerkraut due to the additional ingredients.
Many vegetables can be lacto-fermented, including carrots, beets, green beans, radishes, turnips, and cauliflower. A basic brine of 2 to 3 percent salt by weight of water is used for vegetables that do not release enough liquid on their own. Flavorings such as dill, garlic, peppercorns, and bay leaves are added to the brine. Fermented vegetables are stored in the refrigerator after fermentation to slow further acid development.