Soy sauce isn't grown in the traditional agricultural sense; instead, it's produced through a fermentation process, similar to brewing beer or making wine. The key ingredient involved in its "growth" is a specific type of mold called Aspergillus.
Here's a breakdown of how soy sauce is made, focusing on the "growth" aspect:
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Preparation of Ingredients: Soybeans are steamed until cooked, and wheat is roasted and crushed. These are the primary ingredients that Aspergillus will act upon.
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Koji Production (The "Growth" Phase):
- Aspergillus mold (typically Aspergillus oryzae or Aspergillus sojae, specifically Kikkoman Aspergillus in the reference) is mixed with the steamed soybeans and roasted wheat.
- This mixture is then moved to a carefully controlled environment optimized for Aspergillus growth. Factors like temperature and humidity are precisely regulated.
- Over approximately three days, the Aspergillus proliferates, producing enzymes that break down the soybeans and wheat. This process is called koji making. Koji refers to the mold-inoculated grain mixture.
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Fermentation (Moromi):
- The koji is mixed with salt and water to create a mash called moromi.
- This moromi is then fermented for several months (typically 6 months to several years), allowing various bacteria and yeast to further break down the complex carbohydrates and proteins into flavorful compounds.
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Pressing and Pasteurization:
- After fermentation, the moromi is pressed to separate the liquid soy sauce from the solid remains.
- The raw soy sauce is then pasteurized to kill any remaining microorganisms and stabilize the flavor.
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Bottling: Finally, the soy sauce is filtered and bottled for consumption.
Therefore, while soybeans and wheat are grown as agricultural crops, soy sauce itself is produced through fermentation, where the "growth" refers to the propagation of Aspergillus mold in a controlled environment to create koji. This koji is then the basis for further fermentation and the eventual production of soy sauce.
