Baijiu can be produced from a number of different grains though sorghum is the most common. Sorghum is a very hardy plant, able to withstand many drought conditions, and with a number of defenses against insects and other animals. It can grow in places where most other grains cannot and is a common grain in parts of Africa too. Regions with high amounts of sorghum often made beer from that grain, and sorghum beer is still made in many parts of the world. In China, sorghum also became the dominant grain for distillation.
In the U.S., though other grains, from rye to corn, dominated the spirits industry, sorghum was still used by some to make beer, wine and spirits. For example, in 1950, about 789,000 tons of sorghum were used to make spirits though that significantly decreased to 88,000 tons by the 1970s. And during that 20+ year period, more sorghum was used to create spirits than rye. Currently, the U.S. is the world's largest producer of sorghum and it is fascinating that about 95% of that crop is exported to China!
Other grains that are commonly used for Baijiu, sometimes in blends, include rice, glutinous rice, corn and wheat. Some distilleries have their own secret blend recipes while others freely reveal the proportions in their blends. After the grain or blend has been selected, it is then cooked.
There is an intriguing preparatory step prior to the fermentation phase, the creation of the qu, (pronounced "chew"), a starter culture that is very similar in some ways to the koji used to produce Japanese Sake. To make qu, which was invented around 2000 years ago, they leave a packed brick or ball of damp grains out in a warm place for a month or longer, allowing all sorts of yeasts, fungi and other microorganisms to grow on it. The role of qu is to saccharify the starches in the grain so that yeast can turn the sugars into alcohol. Once ready, the qu is crushed and the powder is mixed in with the grain blend for fermentation.
Most spirits undergo a two step process, where the grains are first saccharified and then fermentation occurs. With Baijiu though, the process entails multiple parallel fermentation, where the saccharification of the starches and the fermentation of the sugars occurs simultaneously. That is similar to the production of Sake, one of the only other alcohols made through multiple parallel fermentation. Within the Sake fermentation vat, there is koji which helps to break the starches down into sugar at the same times as the yeast turns the sugars into alcohol.
In addition, Baijiu is produced through solid-state fermentation, meaning that it occurs without adding water to the grain and qu mix. The fermentation of nearly every other spirit requires the addition of water, making Baijiu more unique. Again though, Sake is one of the few other alcohols which conducts solid-state fermentation, with the creation of koji, though later in the process, additional fermentation does occur with the addition of water.
Once fermentation is complete, you might have remaining either a large pile of grains or a mash which has some liquid which needs to be separated from the liquid. The liquid is referred to as huangjiu, "yellow wine." The mash is not wasted and is commonly returned to the mud pit, kind of like a solera method. Some old mud pits thus end up with some mash that could be over 100 years old or more. This recycled mash may also make some slight changes to the grain proportions of the blend so what you see on the label might not be fully accurate. The fermented solids or liquid is then distilled and steam is often used to heat it. The number of distillations will vary from producer to producer and it is alleged that Kweichow Moutai is distilled forty times, though that doesn't seem credible.
Due to the complexities and diversity of Baijiu, the Chinese government worked at classifying Baijiu, to make it a bit easier to categorize. As such, Baijiu is now generally divided into four main categories, identified by their aroma, which is another thing that makes Baijiu unique. Do you know any other spirit that is categorized by smell? I don't. The four basic categories include mi xiang (rice aroma), qing xiang (light aroma), nong xiang (strong aroma), and jiang xiang (sauce aroma).
Rice aroma is the mildest of the group, with a sweeter flavor and often floral notes. Americans who are starting out with Baijiu might want to begin with this category, the same that if you were getting into Scotch you would start with a mild type first, like Glenmorangie, rather than just jumping in with a highly peaty Scotch like Laphroaig. Light aroma is also relatively mild and smooth, and generally are the least expensive to make.
Strong aroma, the most commonly consumed style, is commonly spicy, pungent and fruity with a strong taste on the finish. Some of these Baijiu can be very expensive. Sauce aroma is full-bodied, with a very strong and savory aroma that might remind you of soy sauce or blue cheese, a very earthy, gamey smell. Generally, these Baijiu undergo numerous distillations and lengthier aging. The strong aromas and flavors are akin in some respects to a peaty Scotch, a profile that isn't for everyone but which aficionados greatly enjoy. To me, the Sauce style reminds me more of Kimoto/Yamahai Sake, which also possesses gamey/earthy flavors and plenty of umami.
Beside these four main categories, you will find a variety of other smaller categories such as Phoenix Aroma, Mixed Aroma, Sesame Aroma and more. There are also flavored varieties, some infused with various medicinal herbs and spices, and even one type that is flavored with pork fat. For example, the Kiukiang Distillery specializes in pork-fat infused rice Baijiu (and I really need to try this style of Baijiu.)
To be continued...