THE CHEMISTRY OF SAKE BREWING. 



209 



t'2) Koji. 



Although the preparation of koji lias been described by 

 several authors as Korschelt^''^ Atkinson,^'^^ and Kcllner,^^^ some 

 remarks may still be made here, as certain points require some 

 further discussion. My own observations of the koji chamber at 

 Toyohashi are the following. The air of this chamber, whose 

 walls are constructed of two layers,'^' has a very mouldy smell 

 and is saturated with moisture The temperature is kept at 

 23-28°C. while of that of the air ranges at that time of the year 

 (December) from about 3° to I0°C. The higher temperature 

 of the koji chamber is at first produced by wooden vats containing 

 hot water, '^^ but later on the respiration of the fungus produces 

 so much heat that it suffices for the start of the next charge. 



In the preparation of koji projaer about 100 grams'^' of tane- 

 -^'^V to 200 litres of steamed rice arc well mixed at 28-35^0. In 

 some factories the rice is not immediately infected after it has 

 cooled down to 28-35°C. but is at first placed in the koji 

 room,''' collected into a heap, and left to stand for 6 hours 

 covered with 2 or 3 layers of mats before the infection takes 

 place. The mixing is accomplished by turning over the rice and 

 spreading it repeatedly. Thus the spores are not only well dis- 

 tributed, but also a most intimate contact of the rice grain with 

 the rice straw mats is accomplished, which is very important. 

 These straw mats, and also the air in the koji room and factory 

 contain numerous yeast cells as I have ascertained by exposing 

 a Petri dish containing sterilised nourishing gelatin to the air of 

 the koji room for 10 minutes and also to the air of the factory. 



(1) Mitthg. (1. deutsch. Ges. Ostasiens Heft 16 (1878). 



(2) Memoirs of the Science Department, Tokio D.iigaku. 1881. 



(3) Bulletin I., No. 5, Agricultural College, Imperial University. Tokio. 



(4) The chambers arc sometimes constructed entirely underground, generally, how- 

 ever, only the lower part is built into the earth. The walls and ceiling consist of 2 

 layers, viz., of rice straw and clay material. The inner wall consists of a layer of rice 

 straw 3 cm. thick which on the outside is covered with a layer of clay 2-3 cm. thick. 

 These chambers built of planks are mostly 2 ni. high, 3-4 m. long and 2-3 m. wide, 

 contain one small window and a door about 1 m. high and 70 cm. wide. The floor is 

 covered with husks of rice upon which is a layer of rice straw (about 3 c. m.) and 

 finally straw mats are spread over it. 



(5) Such I;oji chambers as serve for the manufacture of miso are heated not by hot 

 water but simply by a direct charcoal fire upon the paved floor. 



(6) The quantities vary in different factories. In some factories instead of tane 

 koji the spores alone (about 1-2 c c. to 200 litres of rice) are taken. 



