Baoyuan Vinegar Workshop in Qingxu county, North China's Shanxi province, employs a unique technology of making Shanxi mature vinegar, which is an intangible cultural heritage.

Related: Tech of making Shanxi mature vinegar on display

With more than 3,000 years of history, Qingxu is known as the origin of mature vinegar, one of the four famous vinegars in China, made from sorghum, barley, peas, and other raw ingredients.

First, the raw ingredients must be mixed and braised. Then, it must go through fermentation and solid-state acetic fermentation. Then it's fumigated under high temperatures and leached from a tall crock to a short crock. Finally, the brewing of high-standard Shanxi mature vinegar is finished.

The whole process of making such a vinegar involves only pure natural fermentation, without any chemical catalysts.

Raw ingredients used to make Shanxi mature vinegar at Baoyuan Vinegar Workshop in Qingxu county, North China's Shanxi province, Sept 5, 2013. [Photo by Guo Rong/chinadaily.com.cn]

The stone mill used to grind raw ingredients at Baoyuan Vinegar Workshop in Qingxu county, North China's Shanxi province, Sept 5, 2013. [Photo by Guo Rong/chinadaily.com.cn]