Value Village ／ Food & living
This answer is a draft. It stays unpublished until legal review and source verification are complete.
Arguments about how to brew coffee never end, in Japan as everywhere else. What is less well known is which variable matters first. The guidance published by Japanese roasters puts freshness ahead of technique.
| Variable | Guide |
|---|---|
| Brewing temperature | 90–95°C (194–203°F; about 95°C at the start of pouring, about 90°C at the end) |
| Storage as whole beans | About one month |
| Storage as ground coffee | About two weeks |
The speed of deterioration runs ground coffee > roasted beans > green (unroasted) beans. Grinding increases the surface area, so more of the coffee is exposed to oxygen and oxidation speeds up. The main cause of the loss of flavour is oxidation of the coffee oils that come to the surface of the bean during roasting.
[Verify] The figures are guides based on information published by major Japanese coffee companies. Check against the All Japan Coffee Association's materials or the makers' official materials before publication.
Water straight off the boil is generally described as bringing out bitterness and harsh notes. 90–95°C is the usual guide. Some people also brew light roasts hotter to lift the aroma, and dark roasts cooler to hold back bitterness.
A finer grind extracts more, but over-extraction can make astringency stand out. Adjusting strength with the amount of coffee is easier to control.
Freezing is an option if you cannot finish the beans within the period above. The conditions are an airtight container that keeps out oxygen, and avoiding the condensation caused by taking them in and out. First of all, seal them and keep them away from direct sunlight, heat and humidity.
As above, grinding shortens the storage guide from one month to two weeks.
Equipment improves repeatability, but getting the beans and the water right comes first.
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https://coffee.ajca.or.jp/column/category/howto/
https://www.keycoffee.co.jp/experience/knowledge/detail/coffee-storage-period/
https://www.fsc.go.jp/factsheets/index.data/factsheets_caffeine.pdf
⚠️ Editorial note: the source URLs above were identified by search. Our working environment cannot reach go.jp domains, so the contents have not been checked against the text. Verify every source before publication and record who checked it and when.
What we share here are ideas and everyday practices passed down among people living in Japan, together with general information drawn from public sources. They are not official recommendations, and they are not professional instruction. Practices vary between households and regions.
This is general information. Results vary from person to person and depend on your own conditions and surroundings.
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