FERMENTED tofu, which is known in Chinese as furu or doufuru, is an intriguing condiment in Chinese cuisine.
The texture of fermented tofu is similar to blue cheese or feta cheese. In fact, the tofu is often referred to as “Chinese cheese.”
The origin of the technique used in fermenting tofu isn’t known, but the food was very popular in the Ming Dynasty (1368–1644). In that era, Shaoxing fermented tofu was exported to Southeast Asia.
The process for fermenting tofu begins with small cubes of fresh tofu, arranged in wooden boxes at a temperature of between 15 and 18 degrees Celsius. The mucor, or mold microbe, starts to form in two days. After five days, the tofu cubes are covered with hyphae — the branching filaments that comprise the mycelium of a fungus.
Modern production in a strict bacteria-free environment inoculates high-quality mucor directly onto the tofu to avoid cross-contamination by unwanted microbes.
Layers of salt are added above each layer of tofu, and the cubes are arranged in jars and sealed with a final thick layer of salt on top.
The jars are left to ferment for around eight days. The salt leeches out water from the tofu, hardening it for the next step and inhibiting the growth of unwanted microbes.
A brine is then prepared by mixing Chinese fermented wines or distilled liquor with spices like peppercorns, star anise, ginger, chili and cassia. The tofu cubes are placed in the brine to absorb the flavors, achieving different tastes from the various recipes.
Fermented tofu can be stored in the fridge for very long time. It is served not only as a direct condiment with congee and other foods, but it is also used as an ingredient in various dishes to impart a unique flavor.
There are a few distinctive varieties of fermented tofu. The original fermented tofu is called bai fang, or white cube, and it’s the product commonly referred to as furu in China.
Bai fang originated in the city of Guilin in Guangxi Zhuang Autonomous Region. It has been a popular local delicacy there since the Song Dynasty (AD 960–1279) and is known as one of the “three treasures of Guilin,” alongside Sanhua wine and Guilin chili paste.
This type of fermented tofu is small, soft and smooth. The salty condiment is often used to improve the appetite, especially in the humid climate of Guilin.
The brine used to make bai fang has an obvious aftertaste of alcohol. In addition to the original brine, the fermented tofu cubes are also available in chili or sesame oil for extra flavor.
Most fermented tofu doesn’t have a strong smell or taste. The exception is qing fang, the stinky tofu that is credited to Wang Zhihe in the Qing Dynasty (1644–1911).
According to the tale behind this invention, Wang stored some leftover tofu in a jar in hot weather and then forgot about it. When he opened the jar months later, the tofu cubes had a greenish-gray coating. But the taste wasn’t bad at all, and the texture was very creamy.
Wang became a tofu maker specializing in stinky fermented tofu. It’s said the Empress Dowager Cixi favored the condiment and named it qing fang, which translates as “green cube.”
Today, the most popular qing fang is still sold under the Wang Zhihe label across China. The brand also extends to the famous red fermented tofu, which uses red yeast rice in the brining liquor to achieve a deep color on the outside as well as a special flavor.
Red fermented tofu is often used in stir-fries, stews and braised dishes. It’s very salty but has a hint of sweetness, and it requires a longer aging period than bai fang.
The rose fermented tofu, a variation developed from red fermented tofu, is seasoned with sugared rose petals and is sweeter than the original red fermented tofu.
There are several lesser-known varieties of fermented tofu that are regional specialties.
Chinese cabbage fermented tofu (baicai furu) in Sichuan Province wraps the tofu cubes in cabbage leaves in a clay pot containing soybeans and lets the mixture ferment for around 10 days. This condiment allows one to enjoy pickled and fermented cabbage at the same time.
Tea oil fermented tofu is made by soaking tofu cubes in tea oil brine with spices. And zao fang refers to a fermented tofu that adds distilled grain to the fermentation process.
Ham fermented tofu is a specialty in Zhejiang Province. The fermented tofu is seasoned with Jinhua ham and is dark in color, with a rich flavor.
The most common way to enjoy various types of fermented tofu is as a condiment with light congee, fresh pancakes or noodles. Because of the high level of salt, fermented tofu is typically served in very small quantities.
Strong flavored fermented tofu is added to fatty meat dishes because it helps eliminate some of the greasiness. There is the famous pig trotters braised in red fermented tofu and braised pork belly with red fermented tofu. The tofu can also be used in some vegetable dishes, like fermented tofu flavored water spinach stir-fry.
White and red fermented tofu is popular ingredient in the dipping sauces for hot pots, used with bases of chili sauce, soy sauce or sesame paste sauce. Its saltiness and hint of alcohol complement the meats and veggies cooked in the broth.
Furu cake is a sweet, savory Cantonese-style mooncake pastry that uses peanut crumbs,
cooked glutinous rice flour, fatty pork, fermented tofu and candied winter melon as the filling. The pastry is intensely rich and quite greasy in texture and flavor.