Green tea turns astringent when brewed with boiling water
#0065 Food & cooking
Fact rank
A
That different components dissolve at different temperatures was confirmed by measurements from a national research institute (primary)
Wow rank
A
The opposite of the assumption that tea should be made with the hottest water
Usefulness
S
You can try it every day just by letting the water cool a little
Verification: Supported by evidence
AI verification reports the evidence it found; it does not guarantee that a claim is true.
Green tea tends to turn astringent when brewed with boiling water. Water below 80°C gives a tea with more noticeable umami.
Why
The source of umami (amino acids such as theanine) dissolves even at low temperatures, while the sources of astringency (catechins) and bitterness (caffeine) dissolve more the hotter the water. Brewed in 10°C water, theanine comes out about as much as in 80°C water, but the strongly astringent catechin comes out only about one fifth as much.Evidence
Primary MAFF "Latest agricultural technologies 2021": cold-brewed green tea (research by NARO, the national agriculture and food research organization). Taking the amount extracted at 80°C for 2 minutes as 100%, in water at about 10°C the umami compound theanine and the mildly astringent catechin EGC hardly change, while bitter caffeine falls to about half and the strongly astringent catechin EGCG to about one fifth, giving a tea with more noticeable umami link
Secondary MAFF public-relations magazine aff (April 2017), green tea feature. Amino acids such as theanine, the umami components, come out even at low temperatures of 50°C or more, while catechins and caffeine, the astringent and bitter components, come out at high temperatures of 80°C or more. To bring out umami, brew with water below 80°C link
Secondary Shizuoka Tea Merchants and Manufacturers Cooperative. Umami at low temperature, aroma at high temperature: use cooler water for high-grade sencha and gyokuro to hold back astringency and bring out umami, and hot water for hojicha and bancha to enjoy the aroma link
Notes and limits
Hojicha and bancha are better brewed with boiling water to bring out their aroma.
Derivations
Derived from: アツアツより少し冷ました時の方がうまい
Derived facts: —