Fermented rice is made with yeast and warm water, a sweet dish with a hint of alcohol. The Japanese use fermentation for sushi rice, Thai peoples to make a dessert, and in India it is a very popular way to prepare brown rice. Fermentation with yeast produces alcohol, which gives the rice a tangy taste. In contrast, lactic acid fermentation makes foods like pickles and sauerkraut sour. Eating fermented foods benefits the body in several ways.
In Japan, sushi is made with raw or cooked shellfish or fish, vegetables and fermented rice. Western recipes sometimes call for rice vinegar to be added instead for a similar flavor without the long wait. Originally the fermented rice was discarded and only the fish eaten, but later in the 19th century the two were combined in the familiar sushi eaten today. Sake, or rice wine, is also made from the fermentation of rice into alcohol.
Usually, fermented rice is cooked and allowed to cool for a bit, then mixed with yeast and sometimes a little sugar, as in Thailand’s khao mahk. It then sits at room temperature for several days, until the yeast has had a chance to work. There should be liquid visible in the container when the rice is ready to eat. In India, brown rice is usually preferred, as the widespread vegetarian population seeks to gain as much nutritional value from it as possible. Brown rice is only hulled on the outside, preserving complex carbohydrates from the intact bran and many more nutrients than refined white rice.
Fermented rice can be eaten as is, or shaped into cakes. In India, cooks sometimes prepare dosa pancakes from it. African cuisine relies heavily on fermented foods, including manioc and corn flour, seeds, sorghum and rice. In cultures that still subsist without refrigeration, the flavor imparted by this very old method of preservation has become an essential part of the cuisine. Rather than yeast, some foods like sauerkraut and pickles are fermented by bacteria, which converts the sugar into lactic acid and gives it a sour taste.
Benefits of eating fermented foods include preservation, an improvement in flavor and B vitamin content and also in digestion of those foods. For example, lactose in milk is broken down by bacteria when yogurt is produced, so people who are lactose-intolerant can often safely eat yogurt. When bacteria or yeast have already partially digested the foods, they are typically easier on the human digestive tract. Care must be taken during fermentation not to create an anaerobic environment where deadly Clostridium botulinum bacteria can flourish. Eating fermented rice also restores healthy bacteria to the gut, where they keep the digestive system functioning and help extract nutrition from foods.