What is the difference between koji and yeast

The koji we often hear about now is a kind of bacteria used in the winemaking process, and it is the same yeast we use when steaming buns. So, the wine koji and our yeast are both fermentation principle substances. What are the differences between them? How can we use the koji and yeast correctly? Let us introduce it in detail below.

First of all, yeast: It is a single-celled eukaryotic organism with a cell wall but cannot be autotrophic. When there is sufficient oxygen, it performs aerobic respiration to produce carbon dioxide and water. When there is insufficient oxygen, it performs anaerobic respiration. It is a facultative anaerobic organism. When making wine, it uses anaerobic respiration of yeast to produce alcohol. Aspergillus: It is also a eukaryotic organism and belongs to a type of mold. Of course, mold is also a fungus (it has a cell wall and is heterotrophic), but it is not a single-celled organism. Instead, it is a multicellular filament that remains a loose filament even after maturity. (If after maturity, the filaments grow tightly together to form a "body", which will eventually produce spores, it is also called a fruiting body. It is called a large fungus, such as a very small mushroom.

The second is that the origin of our koji is no longer traceable. The earliest text about koji may be the Zhou Dynasty work "Book of Documents·Shuoming Chapter" which says "If you make wine, you should use koji and yeast." From a scientific perspective, koji actually evolved from moldy grains. The production technology of koji was first comprehensively summarized in the "Qimin Yaoshu" of the Northern Wei Dynasty, and it had reached a very high level in the Song Dynasty.

With the current excellent production technology, due to our proficient mastery of microorganisms and brewing theory, the development of koji has reached a new level in recent years. Our original koji was made from moldy or sprouted grains, which were slowly made into koji suitable for brewing wine. However, different raw materials can now be used to make koji, so the koji and wine can now have different flavors.