Matcha has a reputation for being “grassy” but this is a misunderstanding and usually a sign of poor-quality, low-grade, or improperly processed matcha.
High-grade ceremonial matcha has a very different flavor + aroma profile, shaped by shading, grinding, and the chemistry of tea aroma molecules. Here’s what matcha smell and taste is supposed to be like – based on real scientific research.

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The True Smellof Matcha: Sweet, Umami, Roasted, Herbal, Marine

Researchers describe matcha’s aroma using these sensory descriptors:

✔ Umami & Seaweed-like (key characteristic)

✔ Sweet

✔ Floral

✔ Roasted

✔ Leafy / Green

✔ Woody

✔ Hay / Herbal (in balance, NOT dominant)

This multi-layered aroma comes from dozens of volatile compounds formed by shading, leaf chemistry, enzymatic activity, and stone milling.

High-grade matcha → sweet, roasted, seaweed-like aroma
Low-grade matcha → grassy, harsh, high-fired aroma

Let’s explore why.

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1. Seaweed-like notes → Dimethyl Sulfide, Hexanal, 1-octen-3-ol, 2-pentyl-furan

These compounds contribute to the marine, oceanic, seaweed-like aroma — which is a signature of high-quality matcha.

• Also found in seafood aroma
• Found in Pu’er tea
• Naturally present in shaded green tea leaves

This is why true matcha smells slightly like nori or the ocean — clean and fresh, not fishy. It should be noted that Dimethyl Sulfide is so potent that even trace amounts change aroma quality dramatically.

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2. Sweet, fruity & floral notes → β-glucosidase activity

Shading enhances β-glucosidase, an enzyme that releases aromatic alcohols that smell:

• fruity
• floral
• sweet

This is why good matcha smells a little like spring flowers or fresh fruit beneath the marine layer.

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3. Roasted, nutty notes → Heterocyclic compounds / Maillard products

Stone-milling increases pyrazines, giving high-grade matcha subtle:

• roasted
• nutty
• warm
• toasty

notes, which balance the sweetness and seaweed aroma.

Stone milling = higher roasted notes
Cyclone or bead milling = less aroma complexity

This roasting dimension is a hallmark of good matcha aroma.

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4. Carotenoid degradation → α-ionone, β-ionone, β-damascone

Shading increases carotenoids, which later break down to form:

• fruity
• floral
• elegant
• sweet-green

aromas that make matcha smell soft and rounded, not rough.

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5. Sulfur compounds → aroma enhancers in high-grade matcha

Even in trace amounts, sulfur compounds dramatically enhance aroma:

• Dimethyl sulfide (DMS) — creates the iconic seaweed note
• 1-p-menthene-8-thiol — one of the most powerful aroma compounds known

High-grade matcha contains more sulfur compounds → richer aroma
Low-grade matcha contains fewer → duller, flatter scent

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Why Some Matcha Smells Grassy or Harsh

Medium- and low-grade matcha often shows:

• grassy
• hay-like
• fatty
• high-fired
• woody

notes because:

❌ Less shading → fewer amino acids, more bitterness

❌ Lower carotenoid levels → fewer sweet/floral notes

❌ Less sulfur chemistry → loss of seaweed aroma

❌ Different grinding methods → harsher roasted/off aromas

❌ Lower-quality tencha → higher fatty / rough compounds

These chemical differences explain why cheap matcha tastes “like grass,” while high-grade matcha tastes sweet, deep, and umami.

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What High-Grade Matcha Should Taste and Smell Like

Aroma

• sweet
• roasted
• seaweed-like
• floral
• fresh
• umami-rich
• warmed green leaves
• slight nuttiness
• elegant marine tone

Taste

• sweet (naturally)
• smooth umami
• creamy
• zero bitterness
• velvety mouthfeel
• warm roasted aftertaste

Mouthfeel

• soft
• silky
• no harsh edges
• no dryness
• no astringency

If your matcha tastes bitter or smells grassy, it is not ceremonial quality, regardless of label.

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Athanasios Gerasopoulos, Chemist BSc., MSc. / Founder of Thessmatcha

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Sources:

Luo, Y.; Zhang, Y.; Qu, F.; Wang, P.; Gao, J.; Zhang, X.; Hu, J. Characterization of the Key Aroma Compounds of Shandong Matcha Using HS-SPME-GC/MS and SAFE-GC/MS. Foods 2022, 11, 2964. https://doi.org/10.3390/foods11192964

Zhang, Y., Wu, X., Shi, Y., Qu, F., Qi, D., Qian, W., Zhang, X., & Hu, J. (2025). Identification of key odorants responsible for the seaweed-like aroma quality of Shandong matcha. Food Research International, 204, 115945. https://doi.org/10.1016/j.foodres.2025.115945