Koon-toka-ho (a high-temperature saccharification method) (高温糖化法)
Koon-toka-ho is a Japanese sake-making method used today, in which the starch component of polished rice is gelatinized not by being steamed but by being heated at a high temperature, and then is fermented with the rice malt and yeast that is added at the next stage. This method allows the time and work necessary to be saved, but there exist arguments for and against the quality of sake produced in this way and the retail prices. This method is also called konetsu-ekika-jikomi (literally, making sake by means of liquefaction at a high temperature).
The method of making sake in Koon-toka-ho
First, rice is polished for Japanese sake.
In ordinary sake-making methods, the starch component of that rice is gelatinized by steaming the rice to make the enzyme contained in rice malt work more effectively. However, in this method, the starch component of rice is gelatinized by heating the rice at a high temperature.
However, Koon-toka-ho includes various techniques, and how to add heat at a high temperature depends on the technique used (refer to 'Baisho-Dukuri' and 'Yumai-Dukuri').
Move the gelatinized starch to a tank, together with sake rice malt and sake yeast, and wait until the fermentation there is completed. Compared with the traditional ways, this method makes it possible to make sake much more easily at lower costs using original materials and labor efficiently.
Although the term 'toka' (saccharification) is used, the state is actually 'ekika' (liquefaction) because only alpha amylase is effective in this method.
(Gelatinization alone is done in the 'Baisho-Dukuri' [the brewing method wherein rice is heated in hot air [about 200～400 degrees Celsius]])
Although,about the method, it is often misconceived that "No rice malt is necessary" or "Single fermentation is done, not multiple parallel fermentation," the multiple parallel fermentation is actually done, which requires saccharification with rice malt (the rice malt over 3% of the amount of the original rice is required).
In the sake-making process, lees (sake lees produced by liquefaction) is generated, but most of such lees cannot be used as edible "sake-kasu" (sake lees), and has been disposed of as industrial waste. But as prices of feed, such as corns, has risen steeply, the lees now has been more used as feed for livestock.
However, some sake manufacturers has been investigating the "lees" (sake lees produced by liquefaction) generated by sake brewing from liquefied-rice solution for use.
Koon-toka-moto (the high-temperature saccharification method of sake mash)
It is also called Koon-toka-shubo. This has similar name to Koon-toka-ho, but those two are totally different things. Because this type of moto (yeast mash) is generated at a higher temperature than Yamahaimoto (a manufacturing process of yeast mash) and Sokujomoto (fast brewing method of sake mash), the term of koon (high temperature) is used. Koon-toka-moto is made by culturing yeast in cooled Amazake (sweet mild sake), which is made by keeping steamed rice, rice malt and water at a temperature of 50 to 60 degrees C, with yeast and lactic acid added in it. Using this as syubo (yeast mash), they generate ordinary Japanese sake made from rice and rice molt. In the Kyushu region where it is difficult to produce Yamahaimoto or kimoto due to its air temperature, Koon-toka-moto is used as shubo for making junmaishu (sake made without added alcohol or sugar) and ginjoshu (high-quality sake brewed at low temperatures from rice grains polished to 60 % or less in weight). In the past, nimoto (a manufacturing process of yeast mash) was once made in the same way, in principal, as this moto.