Why Matcha Tastes Umami or Bitter: Theanine and Catechins Explained

Why does one matcha taste smooth, rounded, and deeply savory while another tastes bright, bitter, or drying?

The difference is sometimes explained as “high grade” versus “low grade.” But matcha flavor is more complex than a single ranking. The balance of naturally occurring compounds—including amino acids such as theanine and polyphenols such as catechins—helps shape how we perceive umami, bitterness, astringency, sweetness, and body.

That balance also explains why the most expensive matcha is not automatically the best matcha for every preparation. A delicate matcha that is beautiful with water may become difficult to appreciate in milk, while a more assertive matcha can produce a clearer, more satisfying latte or baked dessert.

The short answer

• Theanine and other amino acids contribute to savory, rounded, umami-rich qualities.
• Catechins contribute to bitterness and astringency, although different catechins do not taste identical.
• Caffeine also contributes bitterness.
• The interaction among compounds matters more than any single number.
• Cultivation, harvest, processing, storage, dosage, water, and temperature all influence the final cup.

In other words, matcha does not taste umami-rich simply because it contains theanine, nor bitter simply because it contains catechins. Flavor comes from balance.

What is theanine?

L-theanine is an amino acid naturally found in tea. Research has shown that it can activate the human T1R1/T1R3 umami taste receptor, helping explain its connection to the savory quality associated with fine green tea.

In sensory terms, theanine is commonly associated with a softer, rounder, more umami-forward impression. It does not act alone: glutamic acid, other amino acids, aroma compounds, caffeine, catechins, and the physical texture of matcha all contribute to the experience.

Matcha is produced from shade-grown tea leaves. Shading changes the chemistry of the developing leaves and helps preserve amino acids while affecting catechin development. This is one reason traditionally produced matcha can offer a distinctive balance of umami and pleasant bitterness.

What are catechins?

Catechins are naturally occurring polyphenols in tea. They are important contributors to the bitterness and astringency of green tea.

Bitterness and astringency are related but different sensations:

• Bitterness is a basic taste perceived by taste receptors.
• Astringency is the drying, tightening sensation felt in the mouth.

Studies comparing major green-tea catechins have found that their perceived bitterness and astringency increase with concentration, and that individual catechins contribute differently. This is why “more catechins” should not be treated as a complete prediction of flavor.

Flavor is an interaction, not a contest

It is tempting to imagine theanine and catechins as opposites: theanine creates umami while catechins create bitterness. The relationship is more interesting.

Research on major catechins and umami amino acids suggests that they interact with one another. Umami-related amino acids can reduce the presentation of bitterness from some catechins, while catechins can also affect perceived umami. The result is not simply one compound overpowering another; it is a combined sensory profile.

This helps explain why a well-balanced matcha can contain noticeable bitterness yet still taste refined. Pleasant bitterness can provide structure, clarity, and a clean finish—especially in a latte, where milk and sweetener soften the cup.

What Marukyu Koyamaen's representative data shows

Marukyu Koyamaen publishes a representative comparison of theanine and catechin levels for several of its matcha varieties. The figures below are examples measured by high-performance liquid chromatography and can vary by production lot.

Important: These values are representative examples published by Marukyu Koyamaen, not guaranteed specifications for every package or lot. The descriptive guidance in the final column is a practical interpretation for product selection, not a laboratory ranking. Towa appears in Marukyu Koyamaen's culinary range but is not included in the published comparison table.

What the numbers do—and do not—tell us

The table shows a broad progression: varieties with relatively more theanine and fewer catechins often feel smoother and more umami-forward, while varieties with stronger catechin presence can deliver more bitterness, astringency, and definition.

But the numbers do not mean:

• More theanine always means “better.”
• More catechins always means unpleasant bitterness.
• A higher-priced matcha is always better for a latte.
• Two matchas with similar percentages will taste the same.

Aroma, cultivar, harvest timing, shading, processing, particle size, freshness, storage, and preparation all matter. The comparison is most useful as a map—not a final verdict.

How this helps you choose matcha

For a smooth, elevated matcha latte

Isuzu offers a more rounded balance of umami and gentle bitterness. It is a Principal Matcha intended for traditional preparation, but it can also create a smoother, more refined latte.

For a bold matcha latte

Aoarashi has a brighter, crisper character that remains noticeable with milk. For everyday latte preparation or larger-volume use, Wakatake, Midorigi, Byakuren, and Rindo offer different balances of umami, color, bitterness, and intensity.

For baking, frozen desserts, and recipes

Suisen, Ayame, and Towa are designed for applications where matcha must remain present alongside flour, fats, sugar, dairy, or other ingredients. Their more assertive bitterness or astringency can be an advantage—not a defect—when used in the right recipe.

For usucha or koicha

Chemical percentages alone should not determine traditional preparation. Choose a Principal Matcha according to the producer's intended use and your preferred balance of aroma, umami, bitterness, and body. Fuller, more rounded varieties such as Kinrin, Unkaku, and Eiju are suitable for koicha as well as refined usucha.

Preparation can change what you taste

Even the same matcha can taste very different depending on how it is prepared.

• More matcha or less water increases concentration and makes both umami and bitterness more apparent.
• Very hot water can make bitterness feel more prominent.
• Milk and sweetener soften bitterness and astringency but can also cover delicate aroma and umami.
• Insufficient sifting or whisking can create clumps and an uneven texture that affects perceived flavor.
• Improper storage can diminish aroma, color, and freshness.

This is why choosing matcha by intended preparation is more useful than relying on a broad label such as “ceremonial grade.”

The best matcha is the one that fits the preparation

Theanine and catechins help explain why matcha varieties taste different, but they are not a quality score. A smooth, amino-acid-rich matcha may be ideal with water. A brighter and more assertive matcha may work better with milk. A more bitter or astringent culinary matcha may produce the clearest flavor in cakes, ice cream, or bread.

Understanding the balance allows you to choose intentionally—not simply by price, popularity, or an undefined grade.

---

Sources

• Marukyu Koyamaen: Matcha for Food Applications
• Narukawa et al. (2014): L-Theanine elicits umami taste via the T1R1/T1R3 umami taste receptor
• Liu et al. (2023): Interaction between major catechins and umami amino acids in green tea
• Nakagawa: Chemical Components and Taste of Green Tea

This article is intended for flavor education and product selection. It does not provide medical or nutritional advice.