Bitterness is a taste; astringency is primarily a mouthfeel.
Bitterness may taste sharp or unpleasant, while astringency makes the mouth feel dry, rough, tight or puckered.
In matcha, caffeine and catechins contribute to bitterness, while catechins and other polyphenols play an important role in astringency.
The two sensations often occur together, which is why many drinkers describe an astringent matcha as simply u201cbitter.u201d
Neither is automatically a defect: quality depends on how well they balance with umami, sweetness, aroma and texture.
In one sentence: Bitterness is a taste detected by receptors, while astringency is mainly a drying, rough or puckering sensation felt across the mouth.
People often describe an unpleasant matcha as “bitter.” Sometimes that is accurate. At other times, the sensation they are trying to describe is astringency: the dry, grippy feeling that can make the tongue, gums or inside of the cheeks feel less lubricated.
The confusion is understandable. Bitterness and astringency often occur together, some tea compounds can contribute to both, and both can linger after swallowing. Yet they are not interchangeable. Learning to separate them makes it easier to understand a matcha’s sensory profile, compare products and diagnose what happened during preparation.
This guide focuses on that distinction. If your main concern is making an unpleasant bowl taste better, read our practical guide to why matcha tastes bitter and how to fix it.
Astringency vs bitterness at a glance
| Feature | Bitterness | Astringency |
|---|---|---|
| What it is | A basic taste | Primarily an oral sensation or mouthfeel |
| How it feels | Bitter, sharp or medicinal | Drying, rough, tightening, puckering or grippy |
| Where you notice it | As a taste in the mouth | Across the tongue, gums, cheeks and other oral surfaces |
| Main sensory pathway | Bitter taste receptors, including TAS2Rs | Complex oral and trigeminal mechanisms involving friction, saliva and tissue sensation |
| Important matcha contributors | Caffeine and several catechins | Polyphenols, including catechins and flavonoids |
| Can it occur alone? | Yes | Yes |
| Can the two occur together? | Very often |
This table is deliberately simplified. The molecular picture is more complicated: individual polyphenols may produce both bitterness and astringency, and researchers are still investigating exactly how different forms of astringency are detected.[1][2][3]
What is bitterness?
Bitterness is one of the basic tastes, alongside sweetness, sourness, saltiness and umami. Bitter molecules activate a family of receptors known as type 2 taste receptors, or TAS2Rs. That receptor activity is converted into neural signals that the brain interprets as bitter taste.[1]
In matcha, caffeine is an important contributor to bitterness. Catechins, including EGCG, EGC, ECG and EC, may also contribute, but not all catechins produce the same sensory intensity. Research on matcha quality commonly associates caffeine with bitterness and tea polyphenols with both bitterness and astringency.[6][7]
Bitterness is not automatically a defect. A mild bitter edge can create structure and contrast with sweetness and umami. The problem is balance: when bitterness overwhelms the sweeter, savoury and aromatic dimensions of the tea, the bowl can feel harsh or one-dimensional.
What is astringency?
Astringency is the dry, rough, tightening or puckering sensation that can develop after consuming tea, red wine, cocoa, certain fruits or other polyphenol-rich foods. An underripe persimmon or banana offers a particularly clear reference point.
Unlike bitterness, astringency is not generally classified as one of the basic tastes. It is primarily understood as an oral somatosensory experience: a physical sensation involving the surfaces of the mouth and the trigeminal sensory system.[2][3]
A traditional explanation is that astringent polyphenols interact with salivary proteins, particularly proline-rich proteins. This can alter the lubricating film in the mouth, increase friction between oral surfaces and create the familiar dry or grippy feeling.[1][3]
That explanation is useful, but it should not be presented as the entire story. Current research also examines interactions with mucins and epithelial cells, as well as direct activation of sensory pathways. Astringency may therefore arise through several overlapping mechanisms rather than one universal reaction.[1][2][3]
Why are bitterness and astringency so easy to confuse?
They frequently arrive in the same sip
Tea contains a complex mixture of caffeine, amino acids, catechins, flavonol glycosides and other compounds. Some are associated mainly with one sensation; others can influence both. Gallated catechins, for example, can be strongly astringent while also contributing bitterness.[1][6]
Both can persist after swallowing
A bitter compound may leave a lingering taste. Astringency can also develop gradually and remain as a dry or rough feeling after the liquid has gone. In sensory research, the timing of the two perceptions can overlap, which makes them harder for an untrained drinker to label correctly.[3]
Everyday language favours “bitter”
Most people learn the word bitter early. Far fewer are taught to identify astringency as a separate sensation. “Bitter” therefore becomes a catch-all term for sharpness, dryness, roughness and other forms of sensory discomfort.
Matcha is a suspension, not a filtered infusion
With matcha, the powdered leaf remains in the drink. Particle size, milling and dispersion can affect texture and the way the beverage coats the mouth. A rough or poorly dispersed matcha may therefore feel harsher even when the sensation is not caused entirely by bitter taste. Research comparing milling methods has found measurable differences in matcha’s sensory properties, including astringency, richness and bitterness.
Which matcha compounds contribute to each sensation?
It is tempting to say “caffeine equals bitterness” and “catechins equal astringency,” but that is too neat.
Caffeine
Caffeine is an important bitter compound in matcha and green tea. Its concentration varies with the plant material, cultivar, growing conditions and processing.[5][6]
Catechins
Catechins are tea polyphenols. They include EGCG, EGC, ECG and EC, among others. They are strongly associated with tea’s bitterness and astringency, with gallated and ester-type catechins often producing greater sensory intensity than non-gallated forms.[1][6]
Other flavonoids and polyphenols
Matcha astringency cannot be reduced to EGCG alone. Recent cultivar research identified several flavonoids, including quercetin and kaempferol glycosides, as important contributors to astringency, alongside EGCG.[8]
Amino acids
Free amino acids such as theanine and glutamate contribute to sweetness, mellowness and umami. They do not simply erase bitter or astringent compounds, but their presence changes the overall balance and can make those sensations feel less dominant.[5][6]
The sensory quality of matcha is therefore better understood as a ratio and interaction, not as the concentration of a single molecule. A bowl can contain caffeine and catechins yet still taste balanced when sweetness, umami, aroma and texture provide enough counterweight.
A simple tasting exercise
You do not need laboratory equipment to start separating the two sensations. Try this exercise with a matcha you know well.
1. Prepare a familiar bowl
Use your normal ratio and record the amount of powder, water temperature and volume. Consistency matters more than chasing one supposedly perfect recipe.
2. Identify the taste during the sip
While the liquid is in your mouth, ask:
- Is there a distinctly bitter taste?
- Does it resemble unsweetened cocoa, tonic water, coffee or bitter greens?
- Is it balanced by sweetness or umami?
Do not rely on the outdated idea that bitterness is sensed only at the back of the tongue. Taste receptors are not arranged according to the classic “tongue map.”
3. Swallow, then wait
After swallowing, move your tongue gently against the roof of your mouth and inside your cheeks.
Ask:
- Do the surfaces feel less slippery?
- Does the mouth feel dry, rough, tightened or puckered?
- Does the sensation build over repeated sips?
Those physical clues point towards astringency.
4. Use separate ratings
Rate bitterness and astringency independently from 0 to 5. A matcha can be:
- low in both;
- bitter but only mildly astringent;
- astringent without intense bitterness;
- high in both;
- moderate in both but well balanced by umami and sweetness.
This is more informative than giving the drink one general “harshness” score.
Is astringency always bad in matcha?
No. A small or moderate amount of astringency can add structure, freshness and a clean finish. Removing every trace of it would not necessarily produce a more complex or higher-quality drink.
The character matters as much as the intensity. Fine, controlled astringency may feel clean or softly grippy. Excessive astringency can feel coarse, drying, puckering or persistent. Sensory scientists also use multiple sub-descriptors, such as drying, roughing and puckering, because astringency is not one uniform sensation.[1][3]
Personal physiology matters too. Saliva composition, oral sensitivity, previous exposure and other individual differences can influence how strongly a person perceives astringency and bitterness.[1][3] Two people can taste the same bowl and give honestly different descriptions.
Does high-quality matcha have no bitterness?
High-quality matcha is usually valued for balance, not for the absolute absence of bitterness. Shading before harvest changes the leaf’s composition, generally increasing amino-acid-related savoury qualities while limiting some of the catechin development associated with sun exposure.[4][5]
Cultivar and processing also matter. Research comparing matcha varieties shows that tea polyphenols, catechins, caffeine and amino acids interact to shape sensory quality. Cultivar can be a major driver of astringency, and differences remain even when teas are produced under similar conditions.[6][8]
A good matcha may therefore have a gentle bitter note or some astringent structure. Warning signs are more likely to be:
- bitterness that overwhelms every other taste;
- coarse, persistent dryness;
- an unpleasant combination of bitterness and stale aroma;
- a thin profile with no sweetness or umami to create balance.
Can preparation change bitterness and astringency?
Yes, but this topic deserves a separate practical treatment. Water temperature, concentration, powder dispersion and the condition of the matcha can all change the drinking experience. Higher extraction temperatures generally release more caffeine and gallated catechins from tea, while a very concentrated ratio increases the dose of every sensory compound in each sip.[9]
However, preparation cannot completely rewrite the raw material. If a matcha is intrinsically very bitter, highly astringent, stale or poorly balanced, cooler water may soften the experience without turning it into a different tea.
For a diagnostic process and practical adjustments, continue with Why Does Matcha Taste Bitter? Causes and How to Fix It.
The distinction to remember
Bitterness is something you taste. Astringency is something you primarily feel.
In real matcha, they overlap. Caffeine, catechins, other flavonoids, amino acids, cultivar, cultivation and preparation all shape the final perception. Separating the two sensations will not make tasting entirely objective, but it gives you a clearer vocabulary, and a more useful way to understand why one matcha feels smooth and balanced while another seems harsh.
Sources
[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC7321337 – Tannins in Food: Molecular Perception of Astringency and Bitter Taste
[2] https://pmc.ncbi.nlm.nih.gov/articles/PMC4064959 – Astringency: A More Stringent Definition
[3] https://www.mdpi.com/2304-8158/9/8/1124 – Sensorial Perception of Astringency
[4] https://pmc.ncbi.nlm.nih.gov/articles/PMC7796401 – Health Benefits and Chemical Composition of Matcha Green Tea
[5] https://pmc.ncbi.nlm.nih.gov/articles/PMC11049459 – Matcha Green Tea: Chemical Composition
[6] https://pmc.ncbi.nlm.nih.gov/articles/PMC10900760 – Metabolomics of Matcha from Different Tea Varieties
[7] https://pubmed.ncbi.nlm.nih.gov/34537612 – Physicochemical Indicators for Matcha Sensory Quality
[8] https://pubmed.ncbi.nlm.nih.gov/39986794 – Effect of Cultivar and Process on Matcha Astringency
[9] https://pubmed.ncbi.nlm.nih.gov/37316075 – Review on Matcha Quality Control
