Basic 2: Why Japanese tea is completely different from other teas

Even the same group of tea plants (Camellia sinensis), Japanese tea is completely different drinks from black tea or Chinese tea, and their handling and purpose are completely different.

Of course, Japanese tea varieties are unique to Japan. Currently, there are more than 120 varieties unique to Japan. This is a characteristic of Japanese tea, which has a lot of rainfall and is rich in organic soil.

However, the biggest difference is whether the tea leaves are oxidatively fermented or not oxidatively fermented. Japanese tea is the only tea product that does not undergo oxidative fermentation. Therefore, the best-by date is stricter than other tea products.

The work of heating and drying the harvested tea leaves is also different between Japanese tea and fermented tea. Japanese tea is steamed to stop oxidative fermentation and then stored away from oxygen. Black tea and Chinese tea are roasted in an iron pot to stop oxidation, but after that, they are exposed to the air to promote oxidation.

Oxidizing tea leaves changes catechin, a type of polyphenol, into a scent component. This is the factor of the unique aroma of black tea and Chinese tea. Catechin has an antioxidant effect that is also suitable for aging care, and has excellent health effects such as a diet effect that breaks down fat and an antiviral effect. However, in oxidatively fermented black tea and Chinese tea, catechins disappear in return for obtaining aroma.

The other is theanine, an umami ingredient. This umami ingredient is the most important factor that determines the value of Japanese tea. The first harvesting tea leaves contains the most theanine, and the umami component decreases with each second and third tea leaves. This is why the first harvesting tea leaves of the year is the most expensive and the subsequent bancha is cheaper. Also, the reason why tea grown in highlands such as mountains is more expensive than that grown in lowlands is that it contains a large amount of theanine, which is an umami ingredient. Theanine not only regulates the autonomic nerves and brings relaxation, but also has the effect of enhancing autoimmune power, and is attracting worldwide attention.

This theanine is a type of protein that is produced in the roots and transferred to tea leaves for use in the growth of tea trees. Generally, all kinds of proteins are altered at about 130 °C. Therefore, theanine is completely lost in black tea and Chinese tea roasted in an iron pot. However, because Japanese tea leaves are steamed, the heating temperature does not exceed 100˚C, and many proteins including theanine are preserved.

This is why I have been offering sencha with water at overseas exhibitions for a long time. Theanine is temperature sensitive and the extraction efficiency varies greatly depending on the extraction temperature. In fact, cold water brewing is the most effective. Since it is served with soft water using the finest sencha such as ZENJIRO Sencha, it must not be delicious. However, hot water is OK for hojicha (roasted green tea). In other words, the optimum temperature depends on the type of tea.

In Japan, soft water is used tapped water naturally in all regions, but there are many countries with hard water overseas such as Europe. When brewed in hard water, it becomes difficult to extract healthy ingredients. Therefore, the required brewing time may differ. In the case of hard water, it is better to boil it once to remove calcium etc. and then use cold water. Volvic is the most famous soft water on the market, and Perrier is the hard water. I often used Volvic when I was on a business trip in Europe.

Summary

• Japanese tea leaves has different and unique varieties
• Japanese tea is the only tea that enjoys the ingredients without being oxidatively fermented.
• The optimum extraction temperature for Japanese tea is different.
• The biggest risk of Japanese tea leaves is oxidation. Therefore, it is important to manage the best before date after opening.