What can go wrong in the soy sauce making process?
The most common problem is that it can get infected with the wrong kinds of mold or bacteria, the way wine does. The solution is to be very clean about the process, and to get the aspergillus in at the same time as you introduce the water. Sometimes the apsergillus packet was mis-handled, though the molds are pretty tough. Make sure that the temperature is controlled (between 10C and 20C, or whatever it tells you on your aspergillus). That helps balance the growth. Follow the recipe. Salt concentration is important. Make sure that the container is not sealed, or it can develop botulism. Make sure that the water level is topped up, or it can evaporate too much. All of these are relatively rare concerns. For the most part, once you’ve made the initial soy-flour “bread”, and innoculated it with the mold, the soy sauce makes itself.
