Zha cai (榨菜, “pressed vegetable”) is a salted, pressed and fermented pickle made from the swollen stem of tuber mustard (Brassica juncea var. tumida). It’s crunchy, salty, savoury and mildly sour, usually seasoned with chili and Sichuan pepper, and eaten in small amounts with rice porridge, noodles and stir-fries. Its home is Fuling in Chongqing, on the Yangtze where the Wu River joins it; zha cai is also made in Yuyao (Zhejiang) and Xiapu (Fujian), but Fuling grows about 70% of China’s tuber mustard and is the largest production and export area (Li et al., 2023).
Where the Name Comes From
The usual account dates zha cai to 1898, when a Fuling pickle merchant, Qiu Shou’an, developed the method and named it for its pressing step, in which wood was used to squeeze the brine out of the tubers. Fuling had large-scale, industrial production by about 1910–1930 (Li et al., 2023, citing Chinese sources).
How It’s Made: Pickled and Pressed Three Times
The traditional industrial method is summed up as “three times pickled and pressed”. The fresh tubers go into brine in a cement pool three times, each time saltier: about 40 g of salt per litre for roughly a week, then 80 g per litre for 20–30 days, then 140–160 g per litre for 4–6 months. After each stage the tubers are taken out and pressed to remove brine. A newer, salt-reduced method uses four stages (about 30, 40, 80 and 100 g per litre), moves the tubers on when their acidity reaches set levels, and finishes in under four months. Either way, the salted tubers are then desalted before being seasoned and packed (Li et al., 2023; Yang et al., 2021).
That’s very different from a quick pickle: by the final stage zha cai has spent months in a brine of around 14–16% salt, which is why it keeps so well and why the commercial product is so salty.
What Ferments It
Zha cai ferments spontaneously, with the microbes coming from the tubers themselves. In a study of a 90-day fermentation at 12% salt, the bacteria after the first month were mainly salt-loving (halophilic) species such as Halomonas and Idiomarina plus lactic acid bacteria (Lactobacillus-related genera and Weissella), with the yeast Debaryomyces increasing as the pH fell and lactic and acetic acid, free amino acids such as glutamic acid, and aroma compounds built up (Zhang et al., 2021). In industrial three-stage pickling, Lactobacillus dominated all three stages, with Latilactobacillus sakei the main species early on (Yang et al., 2021); Lactiplantibacillus plantarum, L. sakei and Debaryomyces hansenii were dominant in the second pickling stage of traditional zha cai (Wang et al., 2026).
The mustard bite comes from the plant’s glucosinolates, mostly sinigrin. Pickling broke them down completely, into pungent isothiocyanates, which peaked around days 21–28, and nitriles (Liu et al., 2022).
Salt, Air and Biogenic Amines
Cutting the salt makes a ferment more vulnerable. Low-salt zha cai fermented with air around it built up 64–161 mg/kg of biogenic amines (compounds such as histamine and tyramine produced by spoilage microbes); fermented under carbon dioxide, which kept air out and favoured lactic acid bacteria, the same pickle had 2–25 mg/kg (Zhang et al., 2023). The home lesson: if you use less salt than a factory, pack the vegetable tightly, keep it covered by its own brine and keep air out.
Like other fermented brassicas, it can also make nitrite in its first days, before the acid builds up; in a fermented cabbage brine nitrite peaked early, at a pH of 4.7, and fell to almost nothing once the pH reached 3.6 (Xu et al., 2024). Eat it once it has turned evenly sour.
How to Use It
- With rice porridge (congee): finely sliced, with a drop of sesame oil.
- In noodles: chopped, as a salty, crunchy topping.
- Stir-fried with shredded pork (zha cai rou si), or in soup with pork and egg.
Rinse or briefly soak it if it’s very salty, and add little or no other salt to the dish. Zha cai sold in sealed pouches has usually been heat-treated, so don’t expect live cultures from it. It’s a cousin of Sichuan’s brine-fermented pao cai; for other fermented mustards see Vietnamese dưa muối and Nepali gundruk, and Sichuan’s other great ferment, doubanjiang.
Making It at Home
Fresh tuber mustard is hard to find outside China (Chinese grocers sometimes have it in winter). The card below uses kohlrabi, a crisp brassica stem that takes the same salting and pressing well; it won’t taste like Fuling zha cai, but it gives the same pressed, crunchy, salty result. It uses two weighed salt stages instead of three months-long brines, so treat it as a fridge pickle, not a shelf-stable one. If a batch goes soft or slimy or grows mould, see the troubleshooting guide. In China, zha cai is a classic side for rice congee, often next to century egg, which is cured rather than fermented.