How to store it
Keep matcha airtight in its opaque tin, in the refrigerator, away from anything aromatic. Sealed and cold, an unopened tin holds well for a year or more from milling. Once opened, aim to finish it within four to eight weeks — that is when the difference is obvious in the bowl.
The one rule people break: bring the tin to room temperature before opening it. Cold powder pulls condensation straight out of warm air, and moisture clumps and dulls matcha faster than anything else. Ten minutes on the counter is enough.
The freezer works for long-term storage of sealed tins, but do not cycle a tin you are drinking daily in and out of it. Avoid clear jars, the cupboard above the stove, and decanting into a big container with lots of headroom air.
Is it still good?
Look and smell before you judge by date. Faded olive colour, a flat or hay-like smell, stubborn clumping, and thin foam that collapses immediately all point to matcha past its best. It is perfectly safe — move it to lattes, baking or an iced drink with milk, where sugar and dairy cover the loss, and open a fresh tin for plain bowls.
The four tools worth owning
Chasen · bamboo whisk
Eighty or a hundred prongs. Soak the tips in warm water for a minute before whisking so they soften and do not snap, rinse with water only, and dry upright on a chasen kusenaoki.
Chashaku · bamboo scoop
Two heaped scoops is roughly 2g — the standard bowl. Wipe it dry; never wash it in soap.
Sieve · furui
The cheapest tool and the biggest improvement. Any fine tea strainer works.
Chawan · bowl
Wide enough for the whisk to move and deep enough not to splash. Warm it with hot water first so the tea does not cool on contact.
An electric frother will make a drinkable bowl and a fine latte. It will not build the dense, fine crema a bamboo whisk does, and it cannot knead koicha at all.
Caring for bamboo
Water only, never soap or the dishwasher. Rinse the whisk immediately, shake it out, and let it dry prongs-up in open air. Treated kindly a chasen lasts a year of daily use; a few broken prongs is the signal to replace it.