Japanese-style soy sauce, known as shoyu, is usually made from an even ratio of soybeans and wheat, koji bacteria and salted water (brine), it is different from traditional Chinese soy sauces that are made with 100% soybeans, koji bacteria and salted water. Japanese-style shoyu tends to be sweeter, clearer and thinner than Chinese soy sauces.
600g Dry Soybean 乾黃豆
600g Wheat 小麥
1.5g Shoyu Koji Bacteria (shoyu koji starter) 醬油麴菌
620g Sea Salt 海鹽
2 liters Water 水
Late evening, January 25, 2015
Preparing the soy beans. Rinse dry soybeans and soak them for 12-16 hours.
Noon, January 26, 2015
Drain the soybeans and steam (or boil) them for 1.5 hours, or until soybeans can be crushed easily between thumb and index finger.
Preparing the wheat. Stir the soft wheat over medium heat in a heavy skillet until golden brown, about 10 minutes. Then grind it coarsely in a grain mill or meat grinder to break the kernel to pieces.
Drain the cooked soybeans. I crush my soybeans to make soybean paste as I want a shorter fermentation period.
In a large mixing bowl, mix the soybean paste with the roasted cracked wheat well. Allow to cool to 30c (85F).
Sprinkle the shoyu koji starter over the soybean-and-wheat mixture and mix very thoroughly.
Transfer the shoyu koji mixture to a shallow tray (I used a large wooden shallow tray). The spread mixture should not be deeper than 2 inches in order to reduce the possibility of hot spots as the mold begins producing its own heat.
Cover the koji tray with towels or cheese clothes and incubate at a temperature range between 27-35c (80-95F).
January 27, 2015
Check the shoyu koji mixture temperature every 4 hours. It should not be higher than 40c (104F) for a long time as it will encourage spoilage bacteria that causes a bad odor. Stir the shoyu koji mixture carefully each time when checking the temperature.
Noon, NJanuary 28, 2015
During 44 hours of fermentation (fermentation period could be shorter or longer, usually between 36~72 hours), there is white and brownish yellow mold appearing on the shoyu koji mixture . The temperature dropped to 25C (77F), which means the fermentation stopped. It's ready to go to the next step.
In a 1 gallon container, combine the salt with water, stir it until salt is dissolved.
Stir in the shoyu koji mixture, mix it very thoroughly. Now the mixture in the container is called Moromi, the fermentation mash of koji, slat and water mixture.
Cover the moromi with a close fitting lid to keep out dust and label it.
Stir it daily for two weeks at warm room temperature, around 25C (77F). Then stir it once a week for six months. The Japanese style shoyu will be ready after six months. Crossed my fingers.
Last Updated on January 28, 2015