How Do You Firm Up Tofu? – What Exactly Is Nigari?

When you think about how tofu is made, I believe a coagulant is one of the most curious topic in it.

Although there are several types of coagulants when making tofu, nigari is the most common material to use in Japan.

Here, I would like to introduce the mystery of nigari, and why Japanese people always use them.

To understand the details of how tofu is made, please check here:
What’s the Difference Between Firm Tofu and Silken Tofu


Table of Contents

What Exactly Is Nigari?
Why Tofu Can Be Firmed Up with Nigari (Bittern)?
Why Not Use Other Coagulants?


What Exactly Is Nigari?

Nigari (にがり) can be translated to “bittern” in English.
It’s a food additive containing magnesium chloride as the main component, which can be obtained from seawater.

Nigari is usually liquid (sometimes powder) that contains a lot of excess minerals made when making salt from seawater.

It is used as a coagulant that turns soy milk into tofu in traditional manufacturing method.


Why Tofu Can Be Firmed Up with Nigari (Bittern)?

You can make tofu by putting nigari in soy milk after making soy milk with soybeans and boiled water.

But, why nigari (bittern) can turn soy milk into tofu?

As I mentioned above, nigari is a type of coagulant, and liquid remaining after removing salt crystals when boiling seawater to make salt.

So, the answer is this:
The main component, magnesium chloride contained in nigari reacts with soy milk protein and hardens.


Why Not Use Other Coagulants?

Comparing nigari (bittern) with other coagulants, you would need higher skills for handling nigari to firm up tofu properly.

However, why this method has been used for a long time?

The answer is the followings:
The main component in nigari, magnesium chloride is easy to dissolve in water. And, coagulation reaction of soy milk would be quick by using nigari.

In terms of the taste of tofu, it can bring out the sweetness of soybeans so well.

If you are interested in other types of coagulants, please check below!
4 Types of Coagulant for Tofu


How was the mystery of nigari?

I hope you enjoyed learning how tofu is made, and feel happy and safe to eat tofu!

As you may know, there are many nutritious soy foods in Japan besides tofu.
If you are interested in other soy product, please check here:
A Guide to Japanese Soy Food

If you are interested in the recipe of homemade tofu, please check here:
How to Make Tofu at Home