Jiang is one of the most basic types of traditional Chinese condiments; yet it is not very well known outside East Asia.
Jiang was probably the predecessor of soy sauce, which is called jiangyou (jiang oil) in Chinese. While soy sauce is liquid, jiang is a paste.
The production process of jiang also resembles that of soy sauce. The main ingredients are soybeans and a starch source: rice, wheat, etc. The starch source is hydrolyzed with a mould, resulting in a very basic type of koji (qu) that is also used for the production of traditional Chinese liquors (baijiu) or the Japanese sake.
Soybeans are soaked and boiled, after which the koji and the boiled soybeans are mixed with salt and water added. That mixture is fermented until a black salty paste is formed.
There are many types of jiang. Some are sweet, while others are fragrant because of the formation of alcohols (produced by added yeast).
Various spices can be added as well. A very famous type is the spicy doubanjiang of Pixian in Sichuan. The sweet jiang used with Peking Duck is made of wheat flour, without using soybeans.
Jiang is presently undergoing a process of modernization. Each type of jiang has its typical flavour (unique mix of the Five Flavours), smell, consistency, colour, etc. Additives are needed to guarantee a mass produced product of consistent quality. Moreover, the time and distance between production and consumption of jiang is also longer and farther than before. This calls for sufficient preservation methods.
Industrial production of jiang is an interesting new market for enzymes. The first enzymatic processes used a single enzyme: a-amylase. Some of the companies produced the enzymes in-house. Later multi-enzyme processes were adopted as well, using a mix of a- and b-amylases and neutral protease.
The following video introduces the industrial production of jiang. It is in Chinese, but food technologists will be able to get the gist.
A major trend is the development of special jiangs for specific dishes. Now you can buy ready to use Peking Duck jiang, dandan noodles jiang (a typical Sichuan type of spicy noodles), huiguo pork jiang (a spicy dish, again from Sichuan), jiang for cooking fish, etc.
You can stir fry some pickled vegetables, add a spoon of dandan noodles jiang, poor it over a bowl of cooked noodles and eat your dandan noodles.
With the proper packaging and marketing campaign introducing these modern jiangs to the Western consumer, these products could mean lucrative business for an astute entrepreneur.
Peter Peverelli is active in and with China since 1975 and regularly travels to the remotest corners of that vast nation. He is a co-author of a major book introducing the cultural drivers behind China’s economic success.