Baijiu production equipment has changed little over the years. What was once bamboo is now stainless steel, but the fundamentals remain the same. Learn more about the specialized tools of the baijiu trade below.
A Chinese fermentation vessel comes in many forms. In the olden days, long before baijiu came to the fore, Chinese brewers fermented all of their grain in stone jars. This is still how it’s done with rice-aroma baijiu, some light-aroma baijiu, and a handful of other spirits. Stone jars provide a neutral surface, take up relatively little space, and can be buried below surface level to insulate fermenting grains in cold climates.
Because of the cold climate in northern China, many distillers bury their fermenting mash jars in the ground to insulate them. Eventually some of them cut out the intermediary and began fermenting the grains in small stone holes in the ground. Fermentation pits can be larger than pots, and thus increase a distillery’s yield. Some modern light-aroma distilleries have even begun using stainless steel pits.
Strong-aroma baijiu distillers continually ferment their grains in mud pits. The earth can actually absorb some of the yeasts and bacteria from the qu and mash over time, becoming integral to the fermentation process. The grains are topped with rice husks and sealed with mud, which is continually mopped down to avoid cracking.
Sauce-aroma baijiu combines strong-aroma and light-aroma baijiu fermentation techniques. Distillers of this style kick off the fermentation process by piling grains until they begin fermenting and then shoveling them into pits lined with stone bricks to continually ferment grains.
Tianguo Pot Still
The tianguo, or “heavenly pot,” still is the older of the two models of traditional Chinese pot still. It consists of a pot of fermented mash with a slotted bottom set atop a cauldron of boiling water. Atop the pot of grain is a pan that collects liquids beneath a pot filled with cold water, the condenser. The water rises from the steaming cauldron into the mash. Once the ethanol begins to steam off the mash, it rises and condenses back into a liquid when it touches the pot filled with cold water. The liquid drips into the pan below and is funneled out of the tianguo as baijiu.
Beijing distillers realized that the baijiu produced during the second pot of cold water was of the best quality, and it is from them that we get the style of light-aroma baijiu known as erguotou, literally “second pot head.”
Chinese Pot Still
More commonly used today is the traditional Chinese pot still. In function and appearance, it resembles a giant dim sum steamer basket. The pot employs much the same design as the tianguo, holding fermented mash on a slotted surface over boiling water. The difference is that it is topped with a lid with a tube that carries the steam into a second compartment, the condenser, which contains a coil surrounded by cold water. The steam condenses back into liquid and emerges from a spout at the base of the condenser as baijiu.
Baijiu is usually aged in neutral surfaces, traditionally in terracotta clay jars. Clay is highly porous and allows plenty of interaction between the distillate and its surrounding environment. Some contemporary distillers also age their products in stainless steel tanks.