Dassai 23 polishes each grain of rice down to just 23% of its original size — removing 77% of each grain to create one of the world's most refined sakes. This extraordinary attention to detail defines Japanese sake brewing, a tradition spanning over 2,000 years. From the magic of koji mold to the precision of the toji master brewer, sake is one of the most complex beverages on Earth.
Each question explores a different aspect of sake — from the science of koji fermentation to the regional styles of Niigata and Nada, from the grading system based on rice polishing to the traditional serving temperatures and vessels. You will be tested on 50 questions covering the full depth of sake knowledge.
You will understand why sake rice is polished, how parallel multiple fermentation achieves the highest ABV of any brewed beverage, what distinguishes junmai from honjozo, and the cultural rituals that surround this ancient drink. Whether you are new to sake or a seasoned enthusiast, there is something to discover.
Koji is steamed rice that has been inoculated with the mold Aspergillus oryzae. The mold produces enzymes that convert the rice's starches into sugars, which yeast can then ferment into alcohol. Koji is the essential ingredient that makes sake brewing possible — without it, rice starch cannot be fermented. The koji-making process takes about 48 hours and requires constant monitoring of temperature and humidity. Koji is also used to make miso, soy sauce, and mirin.
The key difference is that junmai is made with only rice, water, koji, and yeast — no added alcohol. Honjozo has a small amount of distilled alcohol (brewers' alcohol) added during the brewing process, which lightens the flavor and enhances aroma. Junmai tends to be fuller-bodied with richer umami flavors, while honjozo is typically lighter and more fragrant. Both require a minimum rice polishing ratio of 70% (at least 30% of the grain removed). Neither style is inherently superior — they simply offer different flavor profiles.
Sake rice is polished to remove the outer layers of each grain, which contain fats, proteins, and minerals that can create off-flavors during fermentation. The starchy core of the grain produces cleaner, more refined sake. The more rice is polished, the more delicate and aromatic the sake becomes — but also the more expensive, since more raw material is wasted. Daiginjo sake requires polishing to at least 50%, meaning half or more of each grain is removed before brewing begins.
Last updated: April 2026