Wendeng Xuejiu is very popular in Weihai and has a good reputation. When you walk into the factory area of ​​Yiyang Wine Company, a special aroma different from the aroma of wine will hit your nose and refresh your heart. Making koji by yourself using traditional methods is a major feature of Wendeng Xuejiu.

What is koji? The word "koji" in "Ciyuan" means yeast, a fermented product for making wine or sauce. In layman's terms, koji is like the "starter" or "yeast" we use when steaming steamed buns. The quality of wine has a great relationship with koji. More than 4,000 years ago, the Chinese began to use mold to saccharify grains for winemaking. The koji invented by the Chinese working people is a great contribution to the world's winemaking industry. "If you make wine, you only need koji and yeast", which shows that winemaking must rely on the role of koji. "It is better to look at koji than rice, it is better to look at wine than koji, and it is better to look at pulp than wine, because pulp is the yeast." This is exactly the truth. From this point of view, Wendeng Xuejiu insists on making koji by traditional methods, which is not only the inheritance of traditional Chinese winemaking technology, but also fundamentally lays the foundation for the eternal quality of Wendeng Xuejiu.

According to relevant technical personnel, koji is a large aggregation of multiple microorganisms and is the driving force of wine fermentation. To make wine, koji must be made. Making koji is actually the process of expanding the cultivation of winemaking microorganisms. Generally, grains are used as raw materials to enrich microorganisms to make koji, and then koji is used to promote more grains to be brewed into wine through saccharification and fermentation. The quality of koji directly affects the quality and output of wine, so good koji must be used to make good wine. Under the introduction of relevant personnel, the author initially understood the process of making koji in Wendeng Xuejiu. Surprisingly, the entire koji making process, from wheat grinding to finished koji, has 13 processes, and they are closely linked and indispensable.

Stepping on koji, as an important part of koji making, is a hard and complicated job, which is quite particular. The first is its strict organizational form and mutually coordinated working method. There is a "supervisor" in the koji making workshop, who is an experienced person in the company. The koji makers have a strict division of labor. Some are specialized in measuring raw materials and water, some are specialized in mixing materials, and some are specialized in handling. The koji surface is put into the wooden mold and compacted by the koji tampers. There are more than a dozen or even dozens of koji tampers. Each person is required to tread a certain number of times. For example, the first person treads three times in a row, the second person takes over and turns the koji over, treads three times again, and the third person takes over. At most, a block of koji needs to be treaded by 10 people. Then a special person takes out the wooden mold, and there are special people who tread the edges and corners of the koji block, and a special person is responsible for repairing the koji to make it smooth. "Winemaking is a difficult process, and every drop of winemaking knowledge in Wendeng is hard-won." Yu Haixian said. The technicians told the author that the purpose of such a strict koji treading organization system is to tread high-quality koji blocks. The most important thing about treading koji is to make the koji block compact. On the one hand, it is to reduce the breakage of the koji block during transportation, and more importantly, the compactness of the koji block directly or indirectly affects the microorganisms that breed in the koji.

The mold used for making koji blocks is in the shape of a brick, which is also the result of decades of experience accumulated by Yiyang Wine Company. Yiyang people believe that this is the best geometric shape. After years of experiments, they determined it based on the viscosity of the surface, the need for evaporation of koji water, the need for heat dissipation, the strength of the treading, the need for koji block stacking, and the need for transportation. This ancient and traditional method of treading koji has been used by Wendeng wine school for many years. According to the technicians, they also invested in the purchase of mechanical koji pressing in the past few years, but the effect was not ideal. Stepping on koji is a feeling and an experience that cannot be achieved by machines. In a sense, the more traditional and ancient it is, the more vitality and attraction it has. After the koji blocks are formed, they are sent to the koji room for cultivation. In the closed koji room, microorganisms begin to multiply and emit heat. The increase in temperature accelerates the evaporation of water, causing the temperature and humidity in the entire koji room to rise. As soon as the author followed the workers into the koji room, a wave of heat hit him. After staying in it for only a short while, he was already sweating profusely. Master Liu, a shirtless worker, told me that the cultivation temperature of Wendeng Jiuqu can reach 50~60℃. This is the best temperature for making koji.