Last November I found a 30g tin at the back of our cupboard. I had bought it in early March. Nine months. I twisted the lid, expected the grassy hit I get from a fresh tin, and got something closer to dry hay.
It still made tea. It just didn't make my tea.
That's the question I get most often from new customers, usually a week after their first order arrives. "How long do I have before this goes bad?" The honest answer is shorter than most people think, and longer than the bag label usually says.
The short answer
Opened matcha keeps its peak color and flavor for about four to eight weeks. It stays drinkable for up to six months. Past that, the chlorophyll oxidizes, the aroma flattens, and bitterness creeps in. Storage matters more than the unopened expiry date. Air, light, and heat, in that order, are what age it.
Three lines, that's the whole concept.
Why matcha ages so fast
Most teas are leaves. Matcha is a fine powder, which means every grain is a small surface area exposed to the air the moment you lift the lid. The pigment that gives matcha its jade color is chlorophyll, and chlorophyll is fragile. It breaks down under oxygen (turns brown), under UV light (turns yellow-olive), and under temperature swings (loses aroma compounds).
A 2020 study in the National Library of Medicine measured catechin degradation in matcha across storage temperatures and found that EGCG levels — the antioxidant most associated with green tea — drop noticeably faster as ambient temperature climbs. A kitchen counter that swings between 68°F and 78°F across the day is doing more damage than people realize.
The Japan Tea Central Association puts numbers on the color loss: properly stored matcha shows around 30% color deterioration after six months. Improperly stored (clear glass jar, sunny shelf), it can hit that point in eight weeks.
The timeline I actually tell customers
I prepare a daily cup. Most days. So I burn through a 54g tin in about six weeks. Here's the realistic timeline I share with our buyers:
- Week 1 to 4: peak. Color is electric jade. Foam stands up at thick edges. Sweetness on the finish.
- Week 5 to 12: still very good. Color softens a half-shade. Foam is rich. Sweetness is intact for most palates.
- Month 4 to 6: acceptable. Color drifts toward muted green. Astringency moves forward. Fine for lattes, harder to enjoy as straight usucha.
- After 6 months: drinkable but not what you bought. Best for baking or iced milk drinks where dairy masks the dulling.
This is for ceremonial grade. Culinary grade has the same chemistry but lower stakes — you're masking it anyway.
What actually destroys it
Four things, ranked by how much damage they do:
- Air. Every time you open the tin you let in a small amount of oxygen. A snug lid you close immediately is better than a perfect seal you leave off for ten minutes while scrolling.
- Light. Direct sun or fluorescent overhead light bleaches color and breaks flavor compounds. Clear glass jars look pretty on a shelf and cost you weeks of freshness.
- Heat. A spot above the oven, next to the kettle, or on a south-facing counter cooks the powder slowly.
- Humidity. Smaller factor, but it clumps the powder and accelerates the rest.
The fridge is a debated fix. Most Japanese vendors recommend it only for unopened tins. Once you've broken the seal, taking the tin in and out of cold air creates condensation each time, which is the worst kind of damage. Skip the fridge for daily-use tins. Cool, dark cupboard is the answer.
Why we ship our matcha in a tin, not a bag
The 54g Strabella tin is opaque, sealed, and stackable. There's a reason it costs us more than a foil pouch would. A bag re-seals badly — the zipper traps air against the powder each time you fold it. A tin compresses very little headspace and snaps shut to a flat plane every time.
Same logic on the size. 54g lands at roughly 27 servings, around six to eight weeks of daily use for one person. That's the freshness window we want you in. A 100g brick at $32 looks cheaper per gram on paper. It's not, if half of it goes flat before you finish.
Four signs your matcha is past its best
- The color shifted from spring jade toward olive or yellow-green.
- The smell is faint, hay-like, or papery, instead of grassy and slightly sweet.
- The foam doesn't hold. Bubbles collapse within seconds of whisking.
- The taste is bitter without the umami sweetness that usually balances it.
Two of four and it's time to use it up in lattes. Three of four and it's baking matcha. Four of four, compost.
FAQ
Does matcha actually expire?
Not in the sense of becoming unsafe. The powder is shelf-stable as long as it stays dry. What changes is quality, color, aroma, and sweetness, not safety.
Can I store matcha in the freezer?
For an unopened tin yes, for an opened one no. Each time you take it out, condensation forms on the powder. That's the fastest way to turn a six-month window into a six-week one.
Should the bamboo whisk live with the powder?
No. A whisk needs air to dry between uses, and humidity inside a sealed tin will mold its prongs. Store the chasen upright on its holder. I keep mine on the counter next to the Matcha Whisk Set chawan.
How do I tell which date I opened a tin?
I write the open date on a piece of masking tape and stick it to the bottom. Low-tech. Saves arguments with yourself five months later.
Is single-origin matcha worth the extra over a blend?
For daily drinkers, yes. Single-origin powder degrades the same way a blend does, but you start with more of the flavor you're trying to preserve. Our Newport Beach studio sources a single-origin Japanese tin for that reason.
A note from me
We've been making matcha at home since 2023, when our family started Strabella out of the Newport Beach studio. The thing I've learned, over hundreds of tins, is that the most expensive matcha in a clear jar on a sunny shelf is worse than a mid-grade tin in a cupboard. Storage compounds. Sourcing only matters if you protect what you sourced.
If you want to start from a good tin and store it well, our Ceremonial Matcha Powder is $49 for a 54g sealed tin, single-origin, opaque. Pair it with the Matcha Whisk Set ($55) if you don't already have a chasen and chawan you trust. Or browse the matcha ritual collection if you want the whole set.
The cup I'm drinking right now is from a tin I opened on May 14. It's still electric. That's the point.
— Lisa, Strabella
P.S. — If you want the longer version of all of this, the matcha guide covers grade differences, whisking technique, and equipment in one place. And the 60-second latte method is what I make when fresh matcha needs a hot day off.
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