Proper water for Japanese cooking

Proper water for Japanese cooking

I think the majority of people who read my blog are home chefs. Instead of using the ingredients from my recipes, it would be ok to prepare some ingredients that are available in your area. However, I would like to ask you to make a little effort to find some important ingredients which affect the taste of your dishes.

As you may guess based on the title of this article, one of the important ingredients is water. You sometimes see the name “soft water” on my blog. I wrote it in my recipes for some types of dashi and how to cook Japanese rice. Water is very important for those types of dishes and brewing Japanese green tea that I’m going to introduce in the future.

My Australian friend asked me before “why Japanese people always talk about water?”.  She told me that she often hears Japanese people talking about water when she watches NHK world. I’ve also noticed many Japanese people boasting about the importance of water. Especially farmers and chefs are particular about the quality of water used to spawn carp and make good dishes.

Hard water and Soft water

Rainwater soaks into the ground and during this time, the water absorbs minerals such as calcium and magnesium from the ground. The amount of minerals depends on the different types of ground and landform.

In volcanic soils and steep landforms, there are not as many minerals. This type of water is called “soft water”.
On the contrary, water in a region where there is coal underground has a lot of minerals. In the wide plain, water flows gently, slowly, and can take time to absorb minerals. This type of water is called “hard water”.

The hardness of water is determined by the amount of calcium carbonate which is generated through the conversion of calcium and magnesium. The standard on the classification of whether hard water or soft water seems different according to each country.

Here is the WHO standard.

Classification of waterHardness of water
SoftLess than 60 mg
Moderately hard60 mg -120 mg
Hard120 mg – 180 mg
Very hardMore than 180 mg
Hardness of water/ the amount of calcium carbonate milligram(mg) = Ca(mg)×2.5+Mg(mg)×4

How the water hardness affects cooking

Many people drink hard water to have the minerals they need for their health. Especially, when you sweat, you lose a lot of minerals and hard water is perfect for replenishing them.

When it comes to cooking, the calcium in hard water covers the surface of the ingredients and prevents them from absorbing water, also the calcium helps to seal the flavor in the ingredients. Hard water is good for making beef stew, risotto, paella, etc.

In contrast to that, soft water is easily absorbed into the ingredients. It is suitable for cooking fluffy, shiny, and delicious Japanese rice. It’s also easier for soft water to bring out the “umami” of the ingredients. Water softness is important when you make things like dashi/Japanese broth, 煮物(nimono)/ Japanese simmered dishes, or Japanese high-quality green tea.  

Japanese water

I can say Japanese water is generally soft. Although it’s different from region to region, the average hardness of water is around 50 mg in Japan.

There are many areas in Japan where the soil doesn’t have a lot of minerals. 70% of Japanese land is mountainous and hilly.  Japanese annual precipitation is high. So, the water flow is fast and doesn’t take time to absorb minerals. Japanese cuisine has developed thanks to the abundance of clean, soft water.

Japanese people often talk about the difference of water in each region. For example, Kyoto is a valley surrounded by mountains and the water is well known for being clean and soft. The hardness of the water is about 30 mg. This allows people to make delicate flavored dashi/ Japanese broth. With a historical background, the cuisine is very elegant. No wonder many people visit Kyoto to draw spring water. Compared to that, my area Tokyo is in the widest plain in Japan, called 関東平野(Kanto heiya). The hardness of our water is about 60 mg. So Tokyo style dashi and the flavor of the soups are thicker compared to Kyoto. As I described in these two examples above, the differences between the types of water in each region affects the flavor in each dish. It would be fun to explore regional differences when you visit Japan. 

When I was a child, Tokyo tap water had the smell of chlorine. Nowadays with advanced water purification technology, we hardly notice the smell. Most Japanese tap water is good enough to drink.

However, other kinds of water such as filtered and bottled water have been gaining popularity in Japan just like other countries. I’m not sure if it’s common in the world but the water hardness is usually written on the label of bottled water in Japan. 

Here is the hardness of several bottled waters of the world.

Name of bottled waterHardness of the waterCountries of origin
COURMAYEUR2146 mg/LFrance
Contrex1468 mg/LFrance
Gerolsteiner1302 mg/L (sparkling)Germany
S.pellegrino674 mg/LItaly
Perrier 417 mg/L (sparkling)France
evian 304 mg/LFrance
FiJI Water 106 mg/LFiji
CRYSTAL GYSER 67 mg/LAmerica
Volvic 60 mg/LFrance
Pere Ocean 60 mg/LMalaysia
VOSS 40 mg/LNorway
六甲のおいしい水 40 mg/LJapan
サントリー南アルプスの天然水30 mg/LJapan
いろはす27.7 mg/LJapan
ICE FIELD27.5 mg/LCanada
Dasani13 mg/LAmerica
温泉水991.7 mg/LJapan
Aquafine 0 mg/LIndia

There are many different kinds of bottled water. I’m sorry if I didn’t include yours.

Thank you for reading! I hope you find something interesting in this article.

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