Why Is Tofu White When Soybeans Are Green? (ANSWERED)

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Why Is Tofu White When Soybeans Are Green?

Why is tofu white when soybeans are green? This is a commonly asked question that requires a bit of education to answer. Tofu is white, and soy sauce is black, while soybeans are green due to the processes used to make soy sauce and tofu.

In this guide, we will explain how green soybeans give us:

  • White tofu.
  • Black soy sauce.

Let’s get started.

So, why is tofu white when soybeans are green?

soy milk

Tofu is white because it is made from soy milk not directly from soybeans. 

Whether you are vegan, vegetarian, health-conscious, or simply love Asian cuisine, soybeans are amazing. They are served fresh, used to make tofu, soy sauce, soy milk, and other products, such as TVP (textured vegetable protein). In short, soybeans are very versatile.

To understand why tofu is white, you first have to realize that it is not made directly from the soybean. You make tofu from soy milk.

Where does soy milk come from?

soy milk coagulants

You make soy milk by soaking dried mature soybeans, which are actually tan, until they are soft, grinding them into a paste, and then boiling the paste with water to free the milk from the fibrous part of the ground-up soybeans.

When you strain this mixture, you are left with pure soy milk and okara (soy pulp). It is this white soy milk people use to make tofu.

Tofu is the compressed white curd produced when soy milk is mixed with the coagulants calcium sulfate (gypsum), magnesium chloride, or nigari.

That is why tofu is white even though soybeans are green. Its color comes from soy milk,

Why is tofu white when soy sauce is black?

soy sauce

Tofu is white, and soy sauce is black because they are produced through very different processes. 

As detailed above, you get tofu when you separate the soy milk from the fibrous parts of the beans and then treat it chemically to form curds. This is much like the process used by cheesemakers. When the curds are pressed, the resulting cakes are tofu. Tofu gets its white color from soy milk.

Soy sauce is created through a very different process. Whether we are discussing: 

  • Shiro-shoyu, 
  • Tamari-shoyu, 
  • Koikuchi-shoyu, 
  • Usukuchi-shoyu, 
  • Saishikomi-shoyu,
  • any of the Chinese varieties.

They are all produced similarly. 

Soy sauce is made by mixing soybeans, wheat, soy sauce koji (Aspergillus oryzae mold) and allowing the brew to ferment for a minimum of 24 days. 

Chemical changes caused by the Aspergillus oryzae reacting with the amino acids in the grains during the fermentation process cause the sauce to darken. The longer the soy sauce is allowed to ferment, the darker its color and stronger its flavor will become. 

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