Japanese tea

Why Umami Became the Standard for Japanese Tea

Many people who have enjoyed tea for decades tell me they cannot forget the sencha they drank long ago. In fact, Japanese tea before 1950 was grown in a very different way. From the Meiji era to the early Showa era, nitrogen fertilizer was applied at about 10 kg per 10 ares (1,000 m²) a year. From the late 1940s, in pursuit of umami, the amount rose quickly and reached 120 kg per 10 ares in the 1950s, twelve times the earlier level, according to a document published by Japan's Ministry of Agriculture, Forestry and Fisheries.

Nitrogen fertilizer makes tea leaves accumulate amino acids, mainly theanine. Theanine was discovered in tea in 1950, so amino acid content only became a measure of quality after that. The character of Japanese tea changed with it, from a rich aftertaste and a clear flavor to a light, mellow taste with the flavor typical of amino acids. Tea came to be fired more strongly to bring out that flavor, and brewing at very low temperatures to draw out the amino acids became the norm.

However, umami does not equal deliciousness. Umami is the taste of amino acids, the same taste as monosodium glutamate or dashi stock. Theanine-rich sencha is one style of tea, but I do not think it should be the standard of quality.

High-Grade Tea Elsewhere in Asia Is Grown Without Nitrogen Fertilizer

In India, China and Taiwan, farmers and producers who make top-quality tea do not apply nitrogen fertilizer. At the high end, Longjing, Junshan Yinzhen, Phoenix Dan Cong, Tieguanyin and Lishan oolong are grown this way, while lower grades for export are heavily fertilized. For high-grade tea, slow growth in conditions close to nature matters more than speeding up growth with fertilizer.

Teas grown with little or no fertilizer contain few amino acids, so brew them at a high temperature (90 to 95°C) for a short time, from a few seconds up to 10 seconds.