Sun, Pits and Vats: Vinegar in Qingxu

Shanxi mature vinegar takes its name from the province, not from one town, but the county that became its centre is Qingxu, in the Taiyuan prefecture. The record runs back a long way: Jinyang, now Taiyuan, is considered the birthplace of Chinese vinegar, and historical records show a vinegar workshop there in the eighth century BC. The county's place in the modern trade is more recent and concrete. In 1956 the government of Qingxu County joined forces with twenty-one vinegar-making workshops, among them Meiheju, to set up a public-private vinegar factory; in 2011 the Shanxi Mature Vinegar Group became the only demonstration base for the productive protection of national intangible cultural heritage in the condiment industry in the province. In 2006 a traditional mature-vinegar brewing technique was entered in the national intangible cultural heritage list.

The making is a sequence of steps that repeatedly leaves the vat. Shanxi mature vinegar is made from sorghum, barley, peas and other grains through steaming, fermenting, smoking, pouring and drying, with the red starter, Hongqu, used as the koji that starts the fermentation. Two steps in that list carry the seasons. In 1368 the Meiheju workshop worked out the fumigation method, after which what had been white vinegar became black vinegar. In 1644 the same workshop added the method known as fishing for ice in winter and drying in summer - the mixture is worked through the warm months and the liquid is drawn off in the cold ones - and because that takes years to accumulate, the vinegar came to be called mature. The result is judged on five counts: colour, aroma, alcohol, concentration and sourness.

Age is the point of the whole method. Shanxi vinegar is aged with new vinegar rather than with fermented grains, and the aging period is generally nine to twelve months, though some varieties are aged for several years; the Zhenjiang and Baoning vinegars it is often compared with use fermented grains instead, for twenty to thirty days and about a year respectively. Over that time ester and acid convert, alcohols and aldehydes condense and the share of non-volatile acids rises, so an aged vinegar is less sharp than a new one. Winter does its own part: in the old method the ice that formed on the surface of the vat was fished out and the liquid below it drawn off, which is the fishing for ice that gives the method its name and the patience that makes the vinegar mature.