The art of steaming tea
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Terminology: Fukamushi + Asamushi
Unique to Japan, nearly all green teas are steamed during processing (as opposed to pan firing often done in china). A term you often see associated with Japanese tea is ”prefix + Mushi”. This refers the style of steaming the tea has undergone. The prefixes are generally “asa” or light, “chuu”, medium, and finally “fuka”, meaning deep. Whats the difference?
Well, in terms of actual processing asamushi teas are generally steamed anywhere from 15-30 seconds, chuumushi is steamed 30-45 seconds, and anything beyond usually results in Fukamushi. Steaming the tea serves as the main process in halting metabolization in the fresh tea leaf and stops the process of oxidation (oolong and black tea by comparison are allowed to oxidize to varying levels). Steaming is also an important component in the flavor profile of a tea. A general rule is the deeper the steaming, the thicker the brewed tea will become. Quick steamed teas tend to be much lighter in color in the cup - often skewing towards a golden yellow hue as opposed to the deep neon green of chuumushi and fukamushi.
Why? As the tea is steamed it begins to break down. The longer the leaf is in contact with the steam, the leaf becomes more broken with smaller and more abundant particles being produced. When brewing teas that are steamed longer, these particles pass through even the finest strainer, ending up in your cup. The small pieces of floating tea are what constitute the viscous, often soupy appearance and taste of fukamushi tea. Conversely, light steamed asamhushi remains intact and much less, if any, tea passes into the cup.
Steaming practices are often regional. Uji, for example, primarily produces Asamushi, or light steamed teas. This is one reason Uji tea is known for its golden, clear liquor. In Shizuoka prefecture, in the mountainous areas of Kawane is where you’ll likely find Asamushi style teas while down at sea level in the towns like Kanaya and Makinohara, there are many producers making deep steamed fukamushi.
Keep an eye out for these terms when shopping for tea - its a lot of fun to taste the difference steaming makes, even in teas from the same region.