An Introduction to Chinese Vinegars

Fermentation Barrels (Image:Pixabay)

Dr Trevor Ng, Managing Director, Pat-Chun International Limited

Traditionally fermented Chinese vinegar is a delectable condiment with a complex palette of taste. This is well understood by ancient Chinese philosophers who often use vinegar as a metaphor for life itself, as evident in the numerous depictions of “The Vinegar Tasters”. The reaction to the flavors in vinegar is a reflection of their world beliefs:

  • Confucius believes that human behavior should be regulated by traditions, etiquettes and rules, not surprisingly his senses are dominated by the Acetic acids that give vinegar its characteristic sour taste.
  • The Buddha on the hand believes that human life is a form of ethereal suffering, hence he is mostly concerned with the volatile bitterness in the alcohol produced from fermentation.
  • The Taoist tries to find harmony and joy in life and hence their founder Laotzu happily savors the sweetness in the sugars from enzymatic breakdown of grains.

Sourness, bitterness and sweetness are all results from the complex fermentation process of Chinese vinegars. Starch (typically from local grains) are first converted into sugars, they are then converted into alcohol through the action of yeast (like the production of wine and other forms of drinking alcohol), and finally transformed into acetic acid through the action of a bacteria known as Acetobacter.

Chinese vinegars are mostly made through fermentation of grains and cereals. They can be broadly divided into two types – liquid state fermentation (LSF) where the fermentation occurs with the grains submerged in water, and solid state fermentation (SSF) where the fermentation occurs directly on the surfaces of the grain.

Liquid State fermentation – Grains are submerged during fermentation. Yeasts and enzymes are first introduced to breakdown the starches into sugars and alcohol, forming a heady amber colored wine. The wine is then transferred into another fermentation vessel and mixed with a previous batch of vinegar which contains a healthy colony of Acetobacter (sometimes known as the “mother”). The fermentation continues in the second vessel for one to three months, turning the rice wine into vinegar. This is similar to typical western vinegar production techniques.

The vinegar obtained this way is pale amber, with a smooth fruity aroma. The higher acetic acid content makes them ideal for sweet and sour dishes and for pickling vegetables. They generally work well in stir-fries too. The base vinegar of the famous Cantonese Sweet Vinegar is a rice vinegar fermented in liquid state.

Vinegars commonly made from LSF: rice vinegar, Cantonese sweet vinegar, Zhejiang Red vinegar

Solid State Fermentation – A single stage fermentation where enzymes, yeasts and Acetobacter are introduced directly onto moistened grains that is exposed to air. The fermentation happens on the surface of the grains. Progress is continuously monitored, and fermentation halted when the acidity reaches a suitable level by adding salt or heat. The final vinegar is “flushed out” of the grains by pouring hot water over them. Since the fermentation occurs directly on the grain, the vinegar picks up a lot of the smoky/roasted flavors of the fermenting grains and is most suitable for dipping (e.g. spiced vinegar for xiaolongbao dumplings) or marinating vegetables (cucumbers in aged sorghum vinegar).

Vinegars commonly made from SSF: Aged sorghum vinegar, spiced vinegar

Like wine, many types of vinegars can benefit from aging. Fresh vinegar has a sharp flavor, and the aging process allows the chemical compounds created to mature and the flavors to develop. Chinese vinegars can be aged from a few months (rice vinegar) to decades (aged sorghum vinegar) Though all vinegars have the basic aroma and pungency of acetic acid, each is distinctive because they have different levels of acidity, are made with a different starting source of starch/sugars, and are fermented with different strains of micro-organism. This gives naturally fermented vinegars a complexity not present in the manufactured variety. Next time, when you are presented with a plate of vinegar, think of “The Vinegar Tasters”, appreciate the wonderful bouquet of flavors, and contemplate the wonders of natural fermentation.

About the author

Dr Trevor Ng is third generation at the helm of Pat-Chun International Limited. He graduated from Cambridge University, UK, and obtained a doctorate in Mechanical Engineering from Massachusetts Institute of Technology (MIT), America. The Zero Carbon Building in Kowloon Bay is one of his masterpieces.