Shochu (Japanese distilled liquor) / Beer

Shochu (Japanese distilled liquor)

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.

See page 3, Shochu, in 'The Alcoholic Drink Story', Volume 16. In Japanese only. English version is preparing.

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.

*1 Alcohol and aroma compounds vaporize and become gas when heated. The boiling point varies with each substance. In general, the higher the temperature of the mash or solution, the more compounds will become gas.

*2 Sweet potato shochu contains 35% to 40% alcohol after distillation. Water is added to Shochu before shipment.

See page 3, Shochu, in 'The Alcoholic Drink Story'', Volume 2. In Japanese only. English version is preparing.

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.


1. What types of grain are used for brewing beer?

At present, barley, wheat, rye, and oats are used for producing beers. Barley is the most-used grain for producing beer. Normally, it is assumed that beer is made from barley. The Reinheitsgebot (an act concerning the purity of beer) was enacted in Germany in the 16th century. It defined only barley malt, hops, and water as the raw materials for beer brewing. Thus, barley has been recognized since ancient times as the most important raw material for beer. On the other hand, wheat is now also an important raw material for a kind of beer, though it is not used as extensively as barley. Even in the age of the Reinheitsgebot, people also made beer from wheat. Even now, beers with great individuality are produced and beloved, such as Weizenbier and Berliner Weisse.

See page 3, Beer II, in 'The Alcoholic Drink Story', Volume 13. In Japanese only. English version is preparing.

2. What the color of beer comes from?

Beer has many colors, such as gold, reddish-brown, and even black. The difference in colors is caused by the type and amount of malt used. Beer malt is made by drying and scorching green malt (sprouted grains). This process is referred to the 'roast & dry process'. Reddish-brown malt (caramel malt) and black malt (chocolate malt) are produced at a high temperature during the 'roast & dry process'. Various colors of beer can be produced by blending these malts.

See page 2 - 3, Beer II, in 'The Alcoholic Drink Story', Volume 13. In Japanese only. English version is preparing.

2. What are the differences between beer, low-malt beer, and malt-free beer?

The Liquor Tax Law in Japan specifies beer as an alcoholic beverage fermented using specified raw materials: malt, hops, water and grains (wheat, rice, corn, or potatoes). Low-malt beer is made from the same materials as beer. However, less malt is used. Beer is made from 67% or more malt in raw materials. Low-malt beer is made from less than 67% malt.

Malt-free beer (which we refer to as the 3rd beer) does not use malt at all. It is a beer-flavored beverage fermented using sugar, hops, water, corn, green pea protein, soybean protein, soybean peptides, etc. The Liquor Tax Law categorizes malt-free beer as 'other fermented alcoholic beverages.' The 4th beer is a beer-flavored beverage in which spirit derived from barley is added to low-malt beer. Because spirit is added, this beverage is categorized as a liqueur.

See page 6, Beer II, in 'The Alcoholic Drink Story', Volume 13. In Japanese only. English version is preparing.