Matcha shelves are full of tins labelled "Ceremonial Grade", "Premium AAA", or "Restaurant Quality". None of these terms are legally defined — not in Japan, not in the EU, not in the US. No authority checks whether a Matcha actually deserves the claim. Which means: if you want to buy quality Matcha, you cannot rely on labels. You have to be able to judge for yourself.
This guide shows you how — through concrete tests anyone can run at home, and a few numbers that explain why the quality differences are so significant.
The colour test: what the powder reveals on white paper
Dust a small amount of Matcha onto a sheet of white paper. In daylight, you'll know immediately what you're dealing with.
Neon green to vivid jade green — that's the target. This colour comes from a high chlorophyll content built up during the shading period. Tencha plants are shaded to ten to twenty percent of normal light levels for three to four weeks before harvest. The plant responds by increasing chlorophyll production. That process is what makes this intense green possible.
Olive, yellow-green, or dull — the powder is old, oxidised, or came from inadequately shaded plants. Chlorophyll converts to pheophytin — a brownish-olive compound — when exposed to heat and light. This process begins at around 40 °C and continues slowly at room temperature if the Matcha is stored incorrectly.
A brown tinge — a sign of heat damage during milling, or of Tencha processed in impact mills rather than stone mills. Impact mills work quickly and generate localised heat that damages the chlorophyll.
The colour test is not a guarantee, but it immediately eliminates the bottom half of the quality range.
The foam test: making particle size visible
Weigh out 2 g of Matcha, place it in a Chawan, and add 70 ml of water at 80 °C. Whisk with a Chasen using quick M-shaped strokes until foam forms. Then wait and observe.
Good Matcha forms a dense, fine microfoam that holds for 60 seconds or longer. The bubbles are so small they're barely visible — the foam looks almost creamy.
Poor Matcha forms large, irregular bubbles that collapse within ten seconds. The powder starts settling to the bottom.
Why the difference? It all comes down to particle size. Quality Matcha is ground in granite stone mills running at 30 to 40 rpm — slow enough to stay below 40 °C. One mill produces 30 to 40 grams per hour. The result is particles of 5 to 10 micrometres in diameter — finer than icing sugar (roughly 25–40 μm). These particles stay suspended in water and form stable foam.
Industrially milled Matcha from impact or air-jet mills comes in at 15 to 20 micrometres or coarser. Coarser particles sink faster, and the foam breaks down.
The aroma test: what your nose tells you before your mouth does
Open a fresh tin and hold it directly under your nose. The first impression matters.
What you should smell: marine, sweetly vegetal, lightly grassy with a clean freshness — similar to freshly cut grass after rain, but rounder and less sharp. Some describe it as "sea air with a sweet finish".
What signals a problem: musty, hay-like, flat, or a faintly rancid undertone. These off-aromas develop when volatile aromatic compounds — including dimethyl sulphide and linalool, responsible for the marine freshness and sweetness — have broken down through oxidation.
These aromatic compounds are extremely sensitive. Degradation begins within weeks of milling if the powder is not kept under a protective atmosphere (nitrogen or vacuum) and cool storage. A Matcha that has sat on a shelf for months — open, at room temperature — has largely lost its aromatic potential, even if it still looks green.
Why Matcha cannot be cheap: the arithmetic
Quality stone-ground Matcha costs at least €15 to €20 for 30 g. That's not a marketing premium — it's physics and arithmetic.
A stone mill produces 30 to 40 g of Matcha per hour. Thirty grams therefore requires roughly one hour of milling time — plus maintenance, energy, and quality control. Add the cost of Tencha: the dried and de-stemmed tea leaves that are carefully sorted before milling. And before that: the shading infrastructure (nets or traditional straw mats), which must be set up and monitored over several weeks. Hand-picking, steaming, drying, de-stemming — every step is labour-intensive.
Matcha under €10 for 30 g is almost inevitably either industrially milled, made from low-grade Tencha, from an older harvest year, or some combination of all three. That doesn't make it worthless — for baking or latte preparation with plenty of milk, culinary grade is perfectly adequate. But as a cold-brew or classically prepared Usucha, the difference is substantial.
For reference: Japan's JAS standards officially distinguish between 特上 (tokujo, top quality), 上 (jo, superior quality), 中級 (churyu, mid-grade), and 業務用 (gyomukyo, industrial grade). These classifications appear on the Japanese domestic market — European consumers rarely see them on retail labels. "Ceremonial Grade", by contrast, is not a Japanese category at all; it's a Western marketing invention with no standardisation behind it.
Storage: why Matcha ages faster than any other tea
No other tea ages as quickly as Matcha — and there's a structural reason for that. When a tea leaf is ground, its surface area increases dramatically. One gram of Matcha, through its fine particles, has a total surface area of several thousand square centimetres. Oxygen, light, and heat can act on every one of those surfaces simultaneously. Oxidation therefore proceeds far faster than with whole leaves or coarse tea.
What this means in practice:
- Unopened, nitrogen-flushed, in the fridge: keeps until the printed date, typically 12 to 18 months after production.
- Opened, in the fridge, well sealed: optimal quality for 4 to 8 weeks. After that, colour and aroma decline noticeably.
- Opened, at room temperature: quality loss begins within 2 weeks.
Buy 20 g fresh rather than 100 g in reserve. More on the daily routine in the article on everyday Matcha. Good Matcha suppliers state the milling date or harvest year — not just the best-before date. A Matcha that is technically still within shelf life but was milled eight months ago and stored at room temperature ever since is organoleptically stale regardless.
One practical note: when you take Matcha out of the fridge, wait a few minutes before opening the tin. This prevents moisture from condensing on the cold powder — which would accelerate oxidation.
Summary: four questions before you buy
- Colour: Is the powder a vivid green, or does it lean towards olive and yellow?
- Milling: Does the packaging state "stone-ground" (石臼挽き, ishiusu-biki) — and is that claim made credible by provenance information?
- Freshness: Does the supplier give a milling date or harvest year? "Harvest 2024" on a tin being sold in 2026 is not a good sign.
- Price: Below €15 for 30 g, stone-ground quality is structurally almost impossible. That's not a rule of thumb — it's cost accounting.
Anyone who asks these four questions is already making significantly better purchasing decisions than most — regardless of what the tin says. The tests with paper, a Chasen, and your nose cost nothing and deliver more information in a few minutes than any label.
At UNEARTHED, we carry only stone-ground Matchas with a documented harvest year — including the Marukyu-Koyamaen line with Soju, Meiju, and Oju (欧寿), which we taste regularly ourselves and whose quality we can assess directly. Questions about provenance or preparation are always welcome in the gallery or by email.
