Storage, shelf life & stock
Signs Your Matcha Stock Has Degraded
Matcha rarely "goes off" overnight; it fades. Colour turns from bright green towards olive or yellow-green, the aroma flattens, and drinks taste duller or more bitter at the same recipe. The most reliable way to spot degraded matcha is to compare it with a reference you recorded when the bag was opened, not to judge it from memory. Below are the checks, a scoring sheet and what to do with the result.
Set a reference first
When you open a new bag, take two minutes to record:
- A photo of about 1 g of powder spread on white paper, under your normal bar lighting.
- A short note on aroma: fresh, grassy, sweet, vegetal, or whatever words your team uses.
- One drink at your standard recipe, tasted by the shift lead.
Keep the photo with the bag log. Without it, every check is a guess.
The four checks on the powder
1. Colour
Spread a small amount of powder on white paper next to your reference photo, under the same light. Look for a shift from vivid green towards dull olive, yellow-green or brownish. A 2020 study in Food Science and Biotechnology found brightness and greenness of matcha fell as storage temperature and time increased, so colour is a useful visible sign to check first.
2. Aroma
Open the container and smell straight away. Fresh matcha smells clearly of tea. Warning signs are a flat, dusty or hay-like smell, or a smell that is not tea at all, such as coffee, spices or cleaning products picked up in storage.
3. Texture
Press a little powder between your fingers. It should be fine and soft. Small, soft clumps that break easily are normal. Hard clumps, or clumps that feel damp, point to moisture, often from condensation or a wet scoop.
4. Taste
Make a small usucha (powder and water only) rather than a latte, because milk hides changes. Compare with your reference note. Watch for loss of sweetness and depth, a flatter flavour, or bitterness that was not there before.
Scoring sheet
Score each check against the reference: 0 = same as reference, 1 = slight difference, 2 = clear difference.
| Check | Score (0–2) | Notes |
|---|---|---|
| Colour | ||
| Aroma | ||
| Texture | ||
| Taste (usucha) | ||
| Total |
A suggested reading:
- 0–2: In line with reference. Carry on.
- 3–4: Noticeable change. Use it soon, review storage, and check again in a few days.
- 5 or more, or any 2 for aroma or texture: Take it out of service and investigate.
Adjust the thresholds once you have a few bags of experience.
Is it the matcha or the method?
A dull or bitter drink is not always degraded powder. Before you blame the stock, rule out the recipe.
| What you notice | Points to the powder | Points to the method |
|---|---|---|
| Dull colour | Powder itself looks dull against reference | Powder looks fine, but paste stands before serving; see why matcha drinks turn dull |
| Bitterness | Usucha is bitter at standard parameters | Water too hot or dose too high; see why a matcha latte tastes bitter |
| Lumps | Hard or damp clumps in the tin | Not sieved; too little paste water |
| Off aroma | Container smells of other products | — |
Test with a fresh bag or a sample next to the suspect stock, same recipe, same day. If both drinks look and taste the same, the problem is the method.
What to do with degraded stock
- Take it out of service and label it clearly so it is not used by mistake.
- Record it as waste with the reason, the bag's opening date and the batch number.
- Find the cause. Was it stored near heat, opened too often, exposed to moisture, or simply open too long? Storage principles are in how to store matcha in a café.
- Adjust your rule. If bags regularly degrade before they are finished, shorten your "use within" period or use smaller portions. Best-before date vs freshness after opening explains how to set that rule.
- If you suspect an issue with a delivery rather than your storage, keep the bag, note the batch and contact Yumi.
Build the check into routine
- Reference record at every new bag.
- Quick colour and aroma check at every refill of the working tin.
- Full four-point check weekly for any opened bag, and for slow-moving products such as Ceremonial Matcha.
Next step
Set up the reference record on your next opened bag of Ceremonial Barista Matcha or Ceremonial Matcha and add the weekly four-point check to your stock routine.