six leaves · water, time, number of steepings
Built as a memo rather than a table: the thing worth hanging it up for reads across the room, with the full reference in smaller type below it.
Three sizes in one archive — from a sheet on the fridge to a poster on the wall.
Times are for the first steeping. Each next one is the same or shorter: the leaf is already open and gives faster.
Two groups of compounds in the leaf pull in opposite directions. Catechins and caffeine give bitterness and astringency; amino acids, theanine above all, give sweetness and body. The first come out faster the hotter the water is; the second come out in warm water too.
So the same leaf is sweet at 80 °C and bitter at 95 °C over exactly the same time. Gyokuro is brewed at 50–60 °C for that reason: it spent three weeks under shade precisely to build theanine, and boiling water would undo the work.
No thermometer is needed for this. Boiling water poured into a cup and from there into the pot cools noticeably at each transfer — two of them are enough to turn a kettle into sencha water.
Why the numbers can be trusted. Every countable number here is computed from data rather than typed in, and the sheet must pass 7 independent checks before it is allowed to build — how many items there are, the order they come in, and the claim in the highlighted box itself. If one fails, there is no file.
