The major aroma types of Chinese baijiu are divided into twelve categories. Regardless of the specific aroma type, all baijiu share a common characteristic: “the liquor is...”
Chen’s incense.


Chinese baijiu can be stored for over 100 years: Chinese baijiu can be stored for over a hundred years. On June 9, 1996, during the relocation of the former Jinzhou Lingchuan Brewing General Factory, construction workers accidentally unearthed a large wooden container while clearing the site. From the damaged part of the container, they discovered it was filled with a pale-yellow liquid and could still detect a strong aroma of liquor emanating from it. After being identified by senior masters from the distillery, it turned out to be a wooden wine cask—known as a "mujiuhai"—that had been used by the old distillery many years ago to store liquor. Word quickly spread that the distillery had uncovered a treasure, and archaeological experts promptly arrived at the scene. At that time, a total of four wooden wine casks were excavated. By examining the seals affixed to the inner-layer sealing paper of these casks, the archaeologists determined that the liquor had been sealed in the 25th year of the Daoguang reign of the Qing Dynasty—in other words, in 1845. By the time it was discovered in 1996, the liquor had already been preserved for 151 years. These four wooden wine casks, each capable of holding around one ton of liquor, collectively contained approximately four tons of original distilled spirit. Following an appraisal by the State Administration of Cultural Heritage, this batch of tribute liquor, which had been buried for a century and a half, was recognized as “a rare and precious national treasure, unparalleled in the world.” Experts named it “Daoguang Twenty-Fifth,” and it was officially designated as a cultural relic under Document No. [1998] 622 issued by the Administration of Cultural Relics, becoming the nation’s only liquid cultural relic. In 1999, the Daoguang Twenty-Fifth wooden wine cask along with 10 kilograms of its original liquor were added to the collection of the Museum of Chinese History as the last extraordinary national treasure of the previous century.

What changes occur when Chinese baijiu is stored? After baijiu is brewed, it must undergo a certain period of storage before its aroma and flavor become mellow, crisp, smooth, and harmonious, with a lingering, pleasant aftertaste. This is because during the storage process, baijiu undergoes complex physical and chemical changes that alter its taste profile, enhance its mellow character, and lay the foundation for blending and adjusting the finished product. Baijiu is a high-concentration alcohol-water solution containing aromatic compounds; more than 98% of its composition is an alcohol-water solution, while the less than 2% consists of trace aromatic substances—minuscule yet crucial components. These 2% trace components are made up of a diverse array of substances, including abundant alcohols, acids, aldehydes, and esters. The alcohol solution itself is the primary factor determining the stimulating and spicy sensations in the liquor, while the varying concentrations and proportions of these trace components differ from one type of baijiu to another. Coupled with their differing intensities of aroma and flavor, these factors give rise to the distinct aromas and styles characteristic of each variety of baijiu. During storage, both the main components and the trace components undergo different transformations, which is why there are significant differences in taste and style between new and aged baijiu.

[ Physical change 】

(1) Volatilization. During storage, ethanol molecules, water molecules, and aroma molecules form associated molecular clusters via hydrogen bonding. The greater the degree of association, the lower the freedom of ethanol molecules, resulting in a fuller flavor and improved smoothness of the liquor. The stability of these associated structures is influenced by the alcohol content and the duration of storage.

New or ordinary wines often contain certain low-boiling-point undesirable compounds that can cause a strong irritant sensation in the wine and result in an impure aroma and taste. Through prolonged aging, these compounds naturally volatilize, thereby enhancing the wine’s aroma and playing a role in removing impurities while intensifying its fragrance. The contribution of volatilization—changes in flavor compounds in new wines (using sauce-aroma baijiu as an example).

      (2) Binding effect. During the storage of Chinese baijiu, alcohol molecules form large molecular clusters by bonding with water molecules. When consumed, this reduces the harshness and sharpness of the liquor, resulting in a smoother and more mellow taste. Once inside the body, it also slows down the rate at which alcohol molecules are absorbed by the human body.

[ Chemical change 】

(1) Chemical change (redox reaction). Many components in baijiu possess either oxidizing or reducing properties, and during storage, a series of redox reactions take place. For example, alcohols can be oxidized to their corresponding aldehydes, and these aldehydes can further be oxidized to their corresponding acids, thereby causing the alcohol content in baijiu to decrease while the levels of aldehydes and acids increase.

(2) Chemical change (esterification reaction). During the storage of baijiu, alcohols and acids undergo esterification reactions to form corresponding esters. The higher the acid content in baijiu, the easier the esterification reaction proceeds. Compared to oxidation reactions, esterification reactions proceed at a slower rate.

(3) Chemical change (condensation reaction). A condensation reaction is a process in which two or more organic molecules interact and combine via covalent bonds to form a larger molecule, often accompanied by the elimination of a small molecule. For example, when an alcohol reacts with an aldehyde to form a hemiacetal, it can help reduce the harshness of alcoholic beverages.

(Four) Chemical change (hydrolysis reaction). During the storage of baijiu, hydrolysis reactions continuously occur, gradually breaking down esters in the liquor into their corresponding acids and alcohols, thereby causing the flavor of the liquor to change over time. For instance, some low-degree bottled liquors, after leaving the factory, may develop a sour taste, a weak mouthfeel, or even a watery sensation—this is precisely due to excessive hydrolysis of the liquor’s body.

During the storage of aged liquor, alongside changes in physicochemical indicators, there also occur transformations in its flavor profile, leading to significant alterations in its aroma and taste.


For more information, please follow the official WeChat account of Huacheng Wine Group.