Doenjang

Many people often think soy sauce when Asian cuisine is in the conversation. But soy sauce is actually a byproduct of this soybean paste made from dried and fermented soybeans in a process too complicated to describe. 

Doenjang is the brown, textured paste that has an acquired taste popular among Koreans. To produce it, dried soybeans are boiled and stone-ground into coarse bits. This paste is then formed into blocks, which are called meju. The blocks are then exposed to sunlight or warmth. When exposed, dried rice plants are attached to the surface of the soybean blocks.

Dried rice plants are readily available in Korea and are a rich source of bacteria (Bacillus subtilis). The fermentation process begins at this stage. The Bacillus subtilis bacteria reproduce, consuming soybean protein and water in the meju.

The unique smell of the meju is mainly the ammonia produced by the bacteria. One to three months later, depending on the block size, the meju are put into large, opaque pottery jars with brine and left to further ferment, during which time various beneficial bacteria transform the mixture into a further vitamin-enriched substance (similar to the way milk ferments to become yogurt).

Liquids and solids are separated after the fermentation process, and the liquid becomes Korean soy sauce (Joseon ganjang). The solid, which is doenjang, is very salty and quite thick, often containing (unlike most miso) some whole, uncrushed soybeans.