2 BULLETIN 1152, U. S. DEPARTMENT OF AGRICULTURE. 
The process of manufacture which produces soy-bean sauce, or, as 
it is called in Japan, shoyu, begins with the preparation of the in- 
gredients and includes a preliminary mold fermentation, followed 
by a ripening in brine. The soy beans, having been cooked and 
mixed with prepared wheat, are inoculated with the shoyu mold or 
ferment. This mold is procured commercially in Japan under the 
name of " tane-koji," in which form it consists of starchy rice par- 
ticles overgrown with the vegetative and yellow-green fruiting por- 
tions of the fungus! The action of the shoyu mold and its enzymes 
on a mixture of cooked soy beans and crushed roasted wheat, under 
specific conditions of temperature and moisture, produces in from 
three to four days a mold-fermented product known in Japan as 
" shoyu-koji." 
The mold-fermented material is emptied into a strong brine, thus 
producing a mash. ■ Constant daily attention is given to aeration, 
even distribution, and stirring of the solid ingredients. Progressive 
changes take place over a period of from six months to several years, 
until at last mature " moromi," as the mash is designated by the Jap- 
anese, is produced. These changes are due partially to the activity 
of bacteria and yeasts, but chiefly to the enzymes of the mold intro- 
duced into the mash with the koji. Purely chemical alterations in the 
ingredients also appear probable. 
The rather thick, dark-brown mash resulting is siphoned or pressed 
to produce the soy sauce, which is brought to a boil, filtered, and in 
the more modern of the Japanese factories processed or partially pas- 
teurized. The completed sauce is distributed in casks or bottles. 
WORK OF PREVIOUS INVESTIGATORS. 
The first experiments in the Bureau of Chemistry were based on a 
study of available European literature. The principal aim of the 
early reports consulted was not to outline a process of manufacture. 
Rein (17) and Hoffmann (5) give a few pages of directions for 
making soy-bean sauce. Kellner (6) and Prinsen Geerligs (16) deal 
with chemical analyses of soy sauce and related products. The proper 
measures of soy beans and wheat to use in making soy sauce may be 
roughly estimated from a comparison of such analyses. 
Yukawa (27) discusses the carbohydrates of the soy bean in their 
relation to the ripening of shoyu. Suzuki and Furuya (21) discuss 
the chemical changes which occur during shoyu fermentation. Mit- 
suda (13) has published a report on the carbohydrates in soy sauce. 
The organisms concerned in the ripening of the mash or moromi 
are not well known, although attempts to gain this information have 
been made (£, 9, 19, 23). Kita (10) discusses the whole process of 
making soy sauce. The more recent technical literature of Japan 
contains several references of importance to the shoyu industry, in- 
cluding a very practical piece of work on factory coefficients of shoyu 
by Kinoshita (7) and an elaborate manual for shoyu manufacture 
by Togano (25). 
A report on soy manufacture in Kwangtung, China, has been 
published by Groff (It), and data prepared by Shin Chi Yien (26) 
have been made available to the department by Miss Cora D. Reeves 
of Ginling College, Nankin. 
