On the Diastase of Koji. 



301 



still possesses a thin adhering skin which is removed by a very rough 

 process of beating with wooden hammers, the grain being contained 

 in a wooden mortar.* By this operation a large proportion of the 

 grain becomes broken, and is thus rendered unfit for many, purposes, as 

 for eating, and for sake brewing. In the koji manufactory these 

 broken grains, mixed with the thin skin, are converted into koji in the 

 same way as the cleaned and whole grains,, but the product is- inferior 

 in colour, and is put to other uses. Besides the loss of the skin the 

 grains are incomplete, one end of each being sharply curved inward 

 owing to the complete removal of the embryo- from the rough treat- 

 ment it has received.. This alone shows-, that the change which the 

 rice grains undergo in being made into koji cannot resemble a process 

 of germination. 



The rice thus cleaned is next soaked, in water all night, and, on the 

 following morning, it is heated in a current of steam until each grain 

 is just soft enough to be elastic, an operation which takes from four 

 to five hours. After this it is thrown upon mats laid upon the ground, 

 and turned over continuously by the workmen until it is quite cool, 

 the temperature taken on three different occasions being 84°, 86°, and 

 84° F. By this constant working the grains are prevented from 

 cohering into lumps, and the mass feels to the hand quite dry. 



To every two bushels the foreman adds three salt spoonfuls of the 

 spores of a fungus, described by the late~ Mr. Ahlburg as JEurotiurn 

 oxyzece (Ahlb.).f The whole of these spores is mixed with a small 

 portion of the rice, and the mixture is then scattered over the rest of the 

 rice as a husbandman scatters seed over the ground. The mats are 

 folded over at each corner, and the rice thoroughly worked again to 

 ensure a uniform distribution of the spores. After this the rice is 

 gathered into baskets,, and carried into the coolest part of the " growing 

 chamber." This is done about 2 p.m. on the first day. 



In the sake breweries, where koji is made for brewing purposes, the 

 "growing chamber" is of a somewhat rough construction, being 

 formed near the surface of the ground, built up with timber, coated 

 with mud, and covered with straw mats to avoid as much as possible 

 loss of heat. In the koji manufactory proper, however, it is a much 

 more satisfactory place. It consists of a long arched passage, cut in 

 the thick bed of clay which underlies T6ki6 at a depth below the 

 surface of from 15 to 20 feet. In the manufactory at Yushima, in 

 Tokio, with which I am best acquainted, there are in all four of these 



* It is a fact of some interest that if the skin be allowed to remain, the sake pro- 

 duced from such koji is more liable to spoil than when the skin is removed. This 

 is probably connected with the large percentage of albuminoids contained in the 

 skin. 



f " Mittheilungen der Deutschen Gesellschaft fur Natur- und Vplkerkundo Ost- 

 asieus-." 16ter Heft. December, 1878, p. 252. 



