Here, for anyone who doesn't know them, are the beans pre-fermentation.
It is important to note that they must be soy beans. American black beans, Spanish: frijoles negros as used in Latin American cuisine are not suitable. However, although black soy beans are used to prepare fermented beans, not always. Any soy bean can be used and will turn black as a result of the fermentation process.
Traditionally, the beans are salted and left under high heat to ferment in their own enzymes. Industrially produced types are often soaked in brine or salted rice wine to speed up the process. Irrespective of how they are made, they are then dried. Those I saw this week and showed in the previous post are the traditional type.
Here, I usually see the beans in bags like below, but I know they come canned in the west, too.
These umami laden beans have been used in China for over 2,000 years, predating soy sauce. Archeologists have found remains of douchi in Hunan dating back to the 2nd century BCE. The preparation method was first described by Jia Sixie around 540 CE in his 齐民要术 (qí mín yào shù) "Essential Techniques for the Welfare of the People".
