Storage, shelf life & stock
Matcha Shelf Life: Best-Before Date vs Freshness After Opening
Matcha has two clocks. The best-before date on the pack applies to the unopened product stored as the label says; the moment you open the bag, a second clock starts, and that one depends on how you store and use it. The date on the pack tells you the latest point for unopened stock; your own "use within X weeks after opening" rule protects the quality guests actually taste. This guide explains both and how to set that rule.
Clock one: the best-before date
A best-before date is a quality date, set by the producer or packer, for the unopened product under the stated storage conditions. It is not a promise that the matcha will taste the same on the last day as on the first, and it does not cover an opened bag.
For Yumi products, check the date printed on the packaging. For questions about the best-before period of a specific product, or how much shelf life remains when stock arrives, see the B2B FAQ or ask Yumi. This article does not state a period, because it can differ by product and batch.
What to do with the date in practice:
- Write it on your stock list when a delivery comes in.
- Rotate so the earliest date is used first; FIFO for matcha sets out the routine.
- Plan order sizes so stock is used well before the date, not right up to it.
Clock two: freshness after opening
Once a bag is open, air and moisture can reach the powder every time it is opened again. Research on matcha storage found that quality declined faster at higher temperatures and linked the decline to oxygen (Tea Research Journal, 2002); a 2020 study found colour brightness and greenness fell with storage temperature and time. Neither tested light or moisture.
The practical point is that an opened bag kept cool, closed and dry will stay at its best longer than one kept warm and opened often. The storage side is covered in how to store matcha in a café.
Setting your own "use within" rule
No single number fits every café, because it depends on storage, bag size and how fast you use the matcha. You can set a sensible rule in four steps.
Step 1: Calculate how long an opened bag lasts at your pace
Use the formulas for usable quantity and stock duration:
- Usable quantity = purchased × (1 − loss %)
- Theoretical stock duration = usable quantity ÷ daily use
Worked example. One 1 kg bag, 5% loss, 40 lattes a day at 2 g:
- Usable quantity = 1,000 g × (1 − 0.05) = 950 g
- Daily use = 40 × 2 g = 80 g
- Stock duration = 950 ÷ 80 ≈ 11.9 days, so roughly 12 days
| Daily use | Days to use 950 g |
|---|---|
| 40 g (20 lattes × 2 g) | 950 ÷ 40 ≈ 23.8 days |
| 80 g (40 lattes × 2 g) | 950 ÷ 80 ≈ 11.9 days |
| 10 g (5 pure serves × 2 g) | 950 ÷ 10 = 95 days |
The last row shows why slow-moving products need extra attention.
Step 2: Run a quality check over time
When you open a new bag, record a reference: a photo of the powder on white paper, a short note on aroma, and a test drink at your standard recipe. Repeat the same check at fixed intervals, for example weekly, and compare. Signs your matcha stock has degraded lists what to look for.
Step 3: Choose the rule
Set your "use within X weeks after opening" at the point where you consistently start to notice a difference, minus a margin. If an opened bag lasts much longer than that at your pace, the bag is too big for that product at the bar: decant into smaller, sealed portions or reconsider the pack size.
Step 4: Write it down
- Date of opening on the bag.
- "Use by" date on the bag, calculated from your rule.
- The earlier of that date and the printed best-before date is the one that counts.
Rule worksheet
| Item | Your figure |
|---|---|
| Product | |
| Best-before date on pack | |
| Date opened | |
| Daily use (g) | |
| Usable quantity (g) | |
| Expected days to finish | |
| Your use-within rule (weeks) | |
| Use-by date for this bag | |
| Earlier of use-by and best-before |
What to do when a bag passes your rule
- Check it against your reference photo and a test drink.
- If it still meets your standard, you may decide to use it in drinks where it is less exposed, or adjust your rule after several bags of evidence.
- If it does not, take it out of service. Record it as waste so your ordering reflects reality.
Next step
Start the reference-and-check routine on your next opened bag of Ceremonial Barista Matcha or Ceremonial Matcha, and set your first use-within rule after two or three bags.