Why Does My Matcha Taste Bitter, Grassy or Fishy?
Sep 30, 2026
If your matcha tastes unpleasantly bitter, aggressively grassy or strangely fishy, do not assume that all matcha tastes that way. Some bitterness, vegetal character and savory umami are normal. Harshness usually comes from a combination of the tea itself, the ratio, water temperature, freshness and what style of matcha you are trying to make.
Quick diagnosis
| What you taste | Possible causes | Try first |
|---|---|---|
| Very bitter or harsh | Too much powder, too little water, water too hot, more astringent matcha | Use less powder or more water and let boiling water cool before whisking |
| Very grassy | Normal vegetal character, strong/young profile, matcha intended for mixing | Compare another matcha or prepare it slightly lighter |
| Seaweed-like or marine | Strong umami/savory aroma, cultivar or blend character | Compare it side by side with another matcha before calling it defective |
| Fishy, stale or musty | Storage, age, moisture or simply a flavor you strongly dislike | Check freshness and storage; compare with a newly opened matcha |
| Flat and dull | Old/opened powder, heat/light exposure, too much water | Use fresher matcha and a more concentrated ratio |
Start with the ratio
Matcha is easy to make too strong by accident. A heaped kitchen teaspoon can contain much more powder than a small tea scoop, and a large mug can tempt you to treat matcha like brewed tea.
As practical reference points, Ippodo commonly prepares usucha with about 2 g matcha and 60 ml water at 80°C. Marukyu Koyamaen gives a guideline of roughly 1.5 g with 70 ml water, generally using water cooled to around 70–85°C depending on season and preference.
These are examples, not laws. If your matcha is harsh, change one variable at a time: slightly less powder, slightly more water or slightly cooler water.
Water that is too hot can emphasize sharpness
Boiling water is not automatically “wrong,” but many Japanese tea makers recommend boiling the water first and then cooling it before preparing matcha. Cooler water can make sweetness and umami easier to notice in some matchas, while very hot water can make a bitter or sharp profile feel more obvious.
A useful starting point is around 75–80°C, then adjust according to the matcha and your taste.
Not every matcha is designed to taste gentle when drunk straight
Some matcha is selected for cooking, lattes or mixing with other ingredients. A powder with noticeable bitterness and astringency can work very well through milk or sweets because the stronger character remains recognizable.
That does not make it “bad matcha.” It may simply be the wrong matcha for the drink you are trying to make.
If you want to drink matcha as usucha with only water, look for a product the maker specifically recommends for straight preparation.
What does “grassy” mean?
Matcha is made from tea leaves, so green, vegetal aromas are normal. People describe them in very different ways: fresh grass, spinach, young peas, steamed greens, seaweed or herbs.
Whether that seems pleasant depends on the tea and the drinker. A fresh vegetal note is not the same thing as a stale, swampy or musty flavor.
Why can matcha taste marine or “fishy”?
High-umami Japanese teas can have savory aromas that some people interpret as seaweed, broth or the sea. One drinker may call that “umami”; another may call it “fishy.”
Before deciding that something is wrong, compare the same matcha at a lighter ratio and a second matcha from another producer. If the unpleasant smell remains unusually stale, musty or rancid, storage or freshness may be the issue instead.
Freshness matters
Matcha has a huge surface area because the leaf has been ground into fine powder. Once opened, it is exposed quickly to air, moisture, light and odors.
Keep the container tightly closed and follow the producer's storage instructions. Avoid repeatedly leaving an open tin near steam, a hot stove or strong-smelling foods.
For broader storage guidance, read our guide to storing Japanese green tea.
Should good matcha be completely sweet?
No. Good matcha can include sweetness, umami, bitterness and astringency in different proportions. The useful question is whether those elements feel balanced for the style of tea and preparation.
A small refreshing bitterness can be desirable. An overwhelmingly harsh cup that masks everything else may indicate a mismatch between product, ratio and preparation.
Milk changes the problem
Matcha that feels too sharp when drunk with water may work well in a latte. Milk and sweeteners soften bitterness and can mute delicate aromas, which is why a very subtle matcha is not always the most efficient choice for a milk drink.
Conversely, if you want to understand how a new matcha actually tastes, try it at least once with water before deciding how to use it.
A simple troubleshooting sequence
- Sift the matcha.
- Try about 1.5–2 g with 60–70 ml water.
- Let boiled water cool to roughly 75–80°C.
- Whisk and drink promptly.
- If it is still harsh, reduce the powder slightly or try cooler water.
- If it still tastes unpleasant, compare a fresher or differently positioned matcha.
For preparation fundamentals, continue with How to Choose a Matcha Set and What Matcha Tools Do You Actually Need?.
