The Oxford Companion to Spirits and Cocktails Definition of qu

qu , pronounced similarly to the English “chew,” is a compound of mashed grains containing molds, yeasts, bacteria, and other naturally occurring microorganisms that is used in the production of fermented Chinese foods and beverages. Qu has no ready equivalent in Western winemaking tradition, let alone the English language, but it is the single most important innovation in East Asian winemaking and the distillation that is derived from it.

Qu can be thought of as an all-in-one Chinese alcohol starter kit. Creation of Western grain alcohol relies on a two-step process of converting starches to sugars (saccharification) and then adding yeast to convert sugar to ethanol (fermentation). See saccharification and fermentation. Qu allows Chinese winemakers to simplify the process to a single step: mixing qu directly with steamed grains kicks off simultaneous saccharification and fermentation, creating a fermented beverage known as huangjiu (“yellow wine”), or, in distilled form, baijiu (“white wine”; like most Western languages before the eighteenth century, Chinese uses “wine” to cover spirits as well). See baijiu.

To produce qu, moistened grains are mashed into a paste, which is then formed into a clump or pressed in a mold and allowed to incubate in a carefully manipulated environment—typically a dark, dank room. The process takes up to a month from start to finish and results in a solid grain mass, saturated with fungi, enzymes, and all manner of airborne microorganisms, which is then dried. Before qu is mixed with steamed grains to initiate fermentation, it is crushed into a fine powder.

Because each qu is essentially an ecosystem unto itself, no two qus are alike. The specific admixture of microorganisms that qu harvests from the air depends on geography and climate, so qu lends to Chinese winemaking something akin to the Western notion of terroir: even a slight difference in scenery can produce surprisingly unique results. See terroir.

Qu production has changed little over the years, but the full-scale industrialization of the Chinese alcohol industry in the twentieth century has introduced a few modern twists, the most important of which is the inoculation of grains. By taking samples of the previous batch of mature qu and adding it to the fresh qu during the production process, baijiu distillers are able to ensure greater consistency of flavor over time. As a result, qu recipes are among the most closely guarded trade secrets in the baijiu industry. Visitors to Chinese distilleries will seldom be allowed anywhere near the qu production facilities for fear that a sample of the meticulously cultivated culture might be replicated in a competitor’s laboratory.

History

The earliest historical reference to qu comes from the Book of Records, compiled around the fifth century bce, which states that in prehistoric times there were two popular strains of Chinese alcohol. One was a type of beer made with sprouted grains known as li, and the other was a rice wine made with qu known as jiu. Though we know precious little about these primitive brews, later historians would note that the qu-based drinks were more potent and flavorful, and thus they quickly rendered their competitors obsolete. This is plain enough from the fact that all modern Chinese alcoholic drinks are fermented with qu and that today jiu simply means “alcoholic beverage” in Mandarin Chinese.

Qu became an essential element not only of Chinese winemaking but of the greater Chinese culinary tradition, used in the creation of all-important staples like rice vinegar and soy sauce. As the technique for qu fermentation spread throughout the empire and beyond, it became the basis of winemaking traditions in Japan, Korea, Vietnam, Thailand, and other East Asian lands.

Medicinal qu is qu that incorporates ingredients used in traditional Chinese medicine—herbs, spices, and more exotic additions like deer antlers—into its recipe. This is thought to add depth of flavor and complexity to the resulting alcohol while imparting various holistic benefits upon the tippler. The technique is still used by some contemporary brewers and distillers. Leading rice-baijiu distillery Guilin Sanhua uses a qu that contains a secret medicinal ingredient, and Dongjiu, the innovative distillery behind so-called medicine-aroma baijiu, employs as many as a hundred in its qu recipe. See health and spirits.

Today qu is divided into countless categories and subcategories depending on raw ingredients and production techniques, but there are two principle types: small qu and big qu.

Small Qu

Small qu is a fermentation agent molded into tiny balls or cakes. It can be made from long-grain rice, glutinous rice, or rice flour. Often herbs and spices are added to small qu to enhance an alcohol’s flavor or holistic benefits. It is commonly used as a starter for huangjiu and other rice-based Chinese wines and spirits.

The older of the two principle qus, rice-based small qu was first mentioned in the fourth century horticultural guide Nanfang Caomu Zhuang. It is produced by mashing rice into a paste, forming the paste into balls or cakes, and allowing them to dry on a bamboo sieve. Sometimes qu powder from an earlier batch is added to the surface to further inoculate a strain. See xiao (“small”) qu.

Big Qu

Big qu is a solid-state fermentation agent formed into large bricks. Most big qu is wheat-based, though it can also be made from wheat bran or a combination of wheat, barley, and peas. It is the preferred starter for most popular styles of baijiu.

Mass production of big qu, the last major qu milestone, is believed to have occurred within the last five centuries. To make it, laborers poured grain paste into wooden molds and used their feet to stamp them into dense bricks. Today this is sometimes simulated using a machine press, though some distilleries still employ the classic method. The bricks are partially dried in the sun before being moved into a dark incubation room, where they will be stacked on straw mats with some room left between bricks to encourage growth of microorganisms. Workers will also regularly adjust the moisture levels and position of the bricks to ensure that the growth is evenly distributed. During this incubation period the core temperature of these bricks will rise rapidly, peaking at around 46° C (115° F) to 63° C (145° F), depending on the variety of big qu, which are sometimes classified by core temperature. After some weeks the qu begins to cool down and is allowed to fully dry into its mature form. It is then stored separately for at least a few months to further develop flavor. See da qu.

qu

History

Small Qu

Big Qu

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