Water is vital to sake (rice wine) production. As the saying goes, “Where there is good sake, there is always good water”. Likewise, where there is good sake, the pickles are also very good. Again, this is because of the water.

Similarly, water is important in tofu production, with the phrase “Water is the life of tofu” generally being accepted as the truth. Evidently, the relationship between good water and good food is a fundamental principle of nature.

The water in Kyoto

Since ancient times, Kyoto has been renowned for its delicious tofu. Water is of such vital importance that there are even records of a food connoisseur of the Meiji period (1868 - 1912) who went out of his way to transport water from Kyoto to Tokyo to make tofu. Since tofu is 90% water, water clearly is the life of tofu.
It is said that the water in Kyoto tastes good because it is soft water. The waters of the Soukun Spring in Ginkaku Temple, the well water of the Kamowake-Ikazuchi Shrine, and the waters of the kitchens of Iwashimizu-Hachiman have been venerated as “Reisen” (hallowed spring) or “Reisui” (hallowed waters) and renowned for the quality of the water since ancient times.

This soft water is ideal for tofu making and cooking. The numerical rating scale of calcium and magnesium content represents water hardness, and in terms of numerical values, the term “soft water” refers to water with a hardness of less than 100. Low mineral levels mean that soft water has no distinctive taste, and the Japanese typically find this type of water easier to drink.

The reason behind the transition of tofu production from Nara, where production initially thrived, to Kyoto is thought to be the better quality of water. Kyoto was ideal for tofu production.
On the other hand, hard water with high mineral content is better suited for sake production. This is because calcium salts and magnesium salts act on the yeast to promote the fermentation process.

Although ancient tofu production used well water, it is now practically impossible to use well water today due to regulations imposed by public health departments, etc. In order to make tasty tofu, it is important to remember to be fastidious in the selection of water as well as in the selection of soybeans.