The Fermented Foods of China: A Field Guide

Chinese food relies on fermentation at a structural level that visitors sometimes underestimate. It is not a subset of the cuisine — it is embedded in the seasoning, the sauces, the wine used in braising, the preserved vegetables, and in dishes that present themselves as ordinary stir-fries. Understanding the fermented products that appear in markets and on plates makes the flavour logic of Chinese cooking considerably clearer.

Historical context

Fermented grain products appear in Chinese texts from at least the Zhou Dynasty (1046–256 BCE) — early references to jiang (醬), the precursor to soy sauce, describe a grain-and-salt fermentation used both as flavouring and as a preserving agent. In a period without refrigeration, controlled fermentation was the primary technology for extending food safety across seasons, and this drove the development of fermented products across every province.

Modern Chinese cooking has largely shed the preservation necessity but retained the flavour — fermented products are kept in the kitchen because they taste better, not because refrigerators are unavailable.

Soy-based ferments

Light soy sauce (生抽, shēng chōu): the standard seasoning liquid across Chinese cooking — salted, thin, with a fermented umami quality. Used in marinades, stir-fries, dipping sauces, and braises. The basic flavouring agent in most Chinese savoury dishes.

Dark soy sauce (老抽, lǎo chōu): aged further and mixed with caramel or molasses, producing a thick, dark liquid with less saltiness but intense colour. Used in braised dishes and clay pot preparations for colour and a slight sweetness rather than as a primary seasoning.

Doubanjiang (豆瓣酱, Pixian fermented broad bean and chilli paste): the single most important condiment in Sichuan cooking. Broad beans are fermented with chilli over months to years — longer-fermented versions develop greater complexity. The Pixian county outside Chengdu is the production centre, and the paste is graded by fermentation duration. It is the base of mapo tofu, twice-cooked pork, Sichuan hot pot broth, and dozens of other preparations. The flavour is intensely savoury, moderately spicy, and deeply umami.

Fermented black beans (豆豉, dòu chǐ): dried soybeans fermented to a dense, salty, slightly funky black state. Used in Cantonese stir-fries — the combination of black bean, garlic, and ginger is one of the defining flavour profiles of Cantonese home cooking. Also used in Hunan pork dishes and as a table condiment.

Fermented tofu (腐乳, fǔ rǔ): silken tofu cubes inoculated with mould and fermented in wine or brine. White versions are mild and creamy — used as a condiment with congee or as a braising component. Red versions (红腐乳) are fermented with red yeast rice, producing a pungent, concentrated product used to flavour char siu and Sichuan hot pot broths. Stinky versions (臭腐乳) are what the name suggests — very strongly fermented, eaten in small quantities as a condiment, available at street stalls in Shanghai and Shaoxing.

Grain-based ferments

Shaoxing Hua Diao wine (花雕酒): aged Shaoxing rice wine, amber-coloured, dry and slightly sherry-like. Indispensable in Shanghainese and Zhejiang cooking — used in braising liquids, marinades, and dipping dressings. The standard bottle in a Chinese kitchen. Not the same as Chinese cooking wine (料酒, liaojiu), which is salted to prevent drinking and is an inferior substitute in most dishes.

Baijiu (白酒): grain spirits fermented and distilled to high alcohol (40–60%), made from sorghum or multi-grain mash with solid-state fermentation using a traditional starter called qu. Used in cooking occasionally but primarily consumed as a beverage. The fermentation character of premium baijiu — particularly the sauce-aroma (酱香, jiangxiang) style — involves similar microbial communities to aged vinegar and soy sauce.

Vegetable ferments

Sichuan paocai (泡菜, pào cài): brine-pickled vegetables — cabbage, radish, long bean, garlic, chilli — fermented in sealed clay jars for days to weeks. The result is crisp, sour, and lightly effervescent. Distinctly different from Korean kimchi, which uses dry-salting and chilli paste in a longer fermentation; Sichuan paocai is lighter and relies on natural lactic-acid fermentation in plain brine. Standard accompaniment to Sichuan meals.

Mei cai (梅菜, preserved mustard greens): sun-dried and salted mustard greens from Huizhou, Anhui. The resulting product is dark, concentrated, and intensely savoury — used to flavour steamed pork belly (mei cai kou rou) and to stuff certain baked pastries. The fermentation here is lactic but slow and low-moisture.

Zhacai (榨菜, Sichuan preserved mustable tuber): the knobbly stem of a particular mustard variety, salted, pressed, and fermented in chilli and seasonings. The result is salty, tangy, and crunchy. Sold in foil sachets and widely eaten shredded as a condiment with congee or mixed into noodles. The production centre is Fuling, Chongqing, where the product has GI status.

Zha cai and pickled long beans: similar lactic fermentation applied to green beans, producing a sour, crisp ingredient used as a flavouring agent in minced pork stir-fries (酸豆角炒肉末, a Hunan standard).

Fermented condiments and pastes

Hoisin sauce (海鲜酱, hǎixiān jiàng): a thick, dark, sweet-savoury sauce fermented from soy and wheat, sweetened with sugar and seasoned with garlic and five-spice. Used as a dipping sauce for Peking duck and as a barbecue glaze for Cantonese roast meats. Despite the name suggesting seafood (海鲜, hǎixiān), it contains no fish.

Yellow bean paste (黄酱, huáng jiàng): a fermented wheat and soybean paste used in northern cooking — the sauce for zha jiang mian (Beijing-style meat sauce noodles) is based on this product mixed with meat and reduced until thick.

The unusual end of the spectrum

Stinky tofu (臭豆腐, chòu dòufu): fresh tofu fermented for days to weeks in a brine containing fermented milk, vegetables, and other organic material. The smell is notable from some distance; the flavour is considerably milder than the aroma suggests. Eaten deep-fried from street stalls across Hunan, Shanghai, and Taiwan. A street food experience that some visitors pursue as a point of principle and others avoid entirely.

Century egg (皮蛋, pí dàn): duck or chicken eggs preserved in a mixture of clay, ash, salt, and quicklime for weeks to months. The result is a dark jelly-like egg with a green-grey yolk and distinctive ammonia aroma. Served sliced as a cold appetiser with pickled ginger, or added to congee. The flavour is concentrated and pungent rather than rotten — the process is a controlled alkaline transformation rather than putrefaction.