About Shochu (Japanese distilled liquor)

A booklet detailing the history, manufacturing process, related product information, etc is available in English.

• The Story of Shochu (Shochu 1)(Revised edition)

1. What kinds of potato are used to make imo-shochu (Japanese distilled liquor made from potato)?

Shochu can be made from sweet potatoes, white potatoes, Chinese yams, Japanese yams, taro, yacon, etc. Usually, sweet potatoes are used to produce shochu; thus 'imo-shochu' means shochu made from sweet potatoes. A lot of sweet potato shochu is produced in Kagoshima and Miyazaki prefectures, because good sweet potatoes are harvested there. Recently, other prefectures have begun to produce it. The next most used material for making shochu is the white potato. This shochu is produced mainly in Hokkaido and Nagasaki. In the world, there are distilled liquors made from cassavas, taro, yams and other roots.

2. What are the differences between black koji and white koji?

Koji is used to convert the starch from rice and sweet potatoes to sugars. Originally, yellow koji was used for producing shochu, like that used for Japanese sake. At the end of Meiji era (1868-1912), people started to use black koji that had been used for making awamori (shochu from Okinawa). Black koji makes more citric acid than yellow koji. Citric acid prevents the growth of contaminating bacteria that will spoil shochu mash . Using black koji, manufacturers become able to ferment shochu mash safely in warm districts and the quality of the shochu was improved. Then, a variant of black koji, white koji with white spores was found. The use of this white koji spread rapidly for shochu koji. Shochu made with black koji has a more complex aroma. A study has reported that shochu made with black koji has higher characteristics of the sweet potatoes than that made with white koji.

3. What are vacuum distillation and atmospheric distillation?

Distilled liquor is made by vaporizing*1 the alcohol from a liquid or mash, and then cooling down this vapor to condensation in a different vessel. After distillation, the resultant liquor contains 40% or more of alcohol*2.

In atmospheric distillation, the temperature of the mash rises to almost 100℃, so many compounds are vaporized. Because the mash's temperature rises during distillation, the substances in the mash undergo chemical reactions, and new compounds are created. Some of them are distilled and contained in the distilled liquor.

On the other hand, in vacuum distillation, the pressure in a chamber containing the mash is reduced, If you boil water on the top of Mt. Fuji, the water will boil at 85℃, because the atmospheric pressure there is low. Using this principle, vacuum distillation results in distillation at a lower temperature than atmospheric distillation does. Chemical reactions are slower at low temperatures, so the components in the mash will not change as much. Thus, the atmospheric distillation develops a rich and strong flavor. Vacuum distillation brings about a lighter taste.

4. When rice and barley are used to make shochu are the grains polished?

Rice and barley are polished for Shochu making, as they are for sake making. The rice and barley are polished to make it easier to process them; when they are immersed they absorb water better, enzymes can reach the starch more easily, and koji mold grows better. There is no need to lower the polishing ratio of rice or barley, because these ratios do not affect the flavor of shochu.

Honkaku Shochu and Awamori Contests

Honkaku shochu and Awamori are the Japanese distilled liquor made with a pot still. We hold a Honkaku Shochu and Awamori contest annually with the aim of clarifying the current manufacturing technology and trends in liquor quality, as well as sharing this information with the manufacturers.

The Results of Sake and Shochu Awards (website of National Tax Agency)

Each regional taxation bureau in Japan holds a sake award to raise the technical level of sake manufacturers in each region and these awards contribute to the sound development of the sake brewing industry in Japan.