No. 026 — The astringency of tea

TSURU COLLECTION • N°026

The astringency of tea

Understanding what the cup really makes you feel

A sip of tea can leave the mouth feeling fresh, supple, and almost silky. Another seems to tighten the cheeks, slightly dry out the tongue, or leave a rough sensation on the gums. We then often say that tea is “bitter.” Yet, it is not necessarily bitterness. It is very often astringency.

Astringency is not simply a flavor: it is recognized above all by what the mouth feels after the sip.

◆ ◇ ◆

Learning to taste tea means gradually moving beyond the most immediate words: good, bad, strong, light, sweet, or bitter. Not because these words are useless, but because they sometimes group together very different sensations.

Astringency is probably one of the best examples.

It can be subtle or powerful, brief or persistent, fine or rough. In some cups, it provides structure and makes you want to take another sip. In others, it becomes overwhelming and masks the aromas.

It is therefore neither automatically a flaw nor automatically proof of a great tea.

To understand this sensation, we must look at the leaf, the chemistry of the infusion, our saliva, and our way of preparing tea.

I. What is astringency?

Take a small sip of a fairly bold tea. Swallow it, then gently pass your tongue against your teeth and the inside of your cheeks.

If the mouth feels slightly drier, less lubricated, or rougher, you are probably perceiving astringency.

The experience is different from that of a flavor in the classic sense. Sugar gives a sweet sensation. Certain compounds give a bitter sensation. Astringency, on the other hand, has a strong tactile dimension.

It is generally described by impressions such as:

• dryness;
• tightening;
• roughness;
• a decrease in the sensation of lubrication in the mouth;
• sometimes a slightly chalky or grippy impression.

This explains why the words used by two tasters can be different even though they are describing a similar experience.

◆ ◇ ◆

II. Why does tea become astringent?

Tea naturally contains many phenolic compounds, including polyphenols. Among them are notably catechins, which are particularly important in minimally oxidized tea leaves.

When we steep the leaves, some of these compounds pass into the water. They contribute to the color, structure, and sensations of the liquor.

A major part of the explanation of astringency then lies in their interaction with the mouth.

Saliva is not simply water. It contains various proteins and helps maintain the surfaces of the mouth lubricated.

Several polyphenols can interact with salivary proteins. These interactions contribute to the modification of lubrication and the sensations of dryness and friction that we group under the term astringency.

Research is also continuing to refine our understanding of this phenomenon: astringency does not depend on a single, simplistic mechanism. Molecular interactions, saliva, the surfaces of the mouth, and the physical properties of the beverage all contribute to perception.

Not all catechins produce exactly the same sensation

The different catechins present in tea do not all have the same sensory intensity. Experimental work shows, in particular, that certain gallated catechins present greater astringency than certain non-gallated forms.

Consequently, two teas containing different amounts and different profiles of phenolic compounds can produce very different sensations, even when prepared identically.

III. Bitterness and astringency: two sensations no longer to be confused

This is probably the most common confusion.

You prepare a green tea with very hot water and let it steep for a long time. Tasting becomes difficult. The reflex is often to say: “It is bitter.”

It can indeed be.

But it can also be very astringent—and often both sensations are present together.

Bitterness is identified primarily as a flavor. It belongs to the same broad family of gustatory perceptions as sweetness, sourness, saltiness, or umami, even if their biological mechanisms are different.

Astringency manifests itself more through touch: a dry mouth, a less slippery tongue, tissues that seem to tighten slightly.

This extremely simple exercise gradually allows you to separate the two sensations.

As your palate becomes accustomed, you may even discover teas that present a distinct astringency without excessive bitterness, or vice versa.

◆ ◇ ◆

IV. Is an astringent tea a bad tea?

No.

This answer, however, deserves to be immediately nuanced.

A harsh, drying, and unbalanced astringency can make a cup unpleasant. But a controlled astringency can, on the contrary, contribute to the personality of the tea.

It sometimes brings tension and structure. It prevents certain liquors from appearing weak or monotonous. It can also produce a dynamic sensation: the mouth tightens slightly, then salivation returns.

In an attentive tasting, it is therefore more useful to ask:

“Is this astringency balanced?”

rather than:

“Is there astringency?”

It is exactly like acidity in other beverages or foods: its mere presence is not enough to make a qualitative judgment.

A matter of balance

Imagine two cups.

The first has delicate aromatic notes, a supple texture, and a little final tension that cleanses the palate. This slight astringency can make the tasting more precise.

In the second, the mouth is so dry that the aromas disappear behind the roughness. Astringency then dominates the whole.

The word is identical.

The experience, however, is not.

THE TEA TRIBUNAL

“If my tea is astringent, it is of poor quality.”

Verdict: false.

Astringency is part of the natural sensory profile of many teas. Its presence alone does not allow you to determine their quality.

It depends on the composition of the leaf, but also on the quantity used, the water, the temperature, and the steeping time.

An interesting tea can present a marked but fine and balanced astringency. Conversely, poor preparation can make a tea excessively astringent that would have been much more harmonious with other parameters.

V. Water temperature changes the cup

When a leaf meets water, the infusion does not instantly and uniformly extract everything it contains.

Temperature strongly influences this extraction.

Generally, hotter water accelerates and increases the extraction of many soluble compounds from the leaf. Studies on infusion show, in particular, that temperature and duration conditions significantly modify the extraction of catechins and other substances.

This allows us to understand a very common experience: a mild green tea at a moderate temperature can become much bolder, more bitter, or more astringent when steeped very hot and for a long time.

However, it would be misleading to turn this observation into a rigid rule.

Not all green teas require exactly the same temperature. Not all black teas systematically require boiling water. The shape of the leaf, the manufacturing style, the quantity of tea, the size of the vessel, and the desired result also matter.

VI. Steeping time: a few seconds can count

Time constitutes the second major lever.

The longer the water remains in contact with the leaves, the longer the extraction can continue.

In some Western methods where leaves remain for several minutes in a large teapot, greatly exceeding the planned duration can make the infusion more intense and increase bitter or astringent sensations.

In short and repeated infusions, the reasoning is different: the times may be only a few seconds and evolve gradually over the infusions.

There is therefore no universal number of minutes valid for all teas.

The relevant parameter is the ratio between:

• the quantity of leaves;
• the volume of water;
• the temperature;
• the contact time;
• and the desired result.

The best way to progress remains to change only one parameter at a time.

If your cup is too astringent, reduce the time, for example, while keeping the rest identical. You will then be able to truly observe the influence of this change.

◆ ◇ ◆

VII. Why do two people not feel exactly the same astringency?

Tasting is not a laboratory instrument.

Two people can drink the same infusion and describe its intensity differently.

This does not necessarily mean that one of them is wrong.

Composition and salivary flow, tasting habits, the state of the mouth, foods consumed beforehand, and individual sensitivity can contribute to modifying perception.

This is particularly important for astringency because saliva directly participates in the phenomenon.

Tasting therefore always has two dimensions:

a physicochemical reality in the cup and an individual perception in the person who drinks it.

Learning does not consist in eliminating this subjectivity. It consists in acquiring enough vocabulary and landmarks to be able to describe it with greater precision.

VIII. “Tea tannins”: a shortcut to handle with caution

In everyday language, the astringency of tea is frequently attributed to its “tannins.”

The term can be practical, but it is often used in a very broad and imprecise way.

Tea chemistry includes many phenolic compounds whose nature and proportions evolve with the raw material and the processing of the leaves.

In green teas, catechins occupy an important place. During the manufacturing of black teas, enzymatic oxidation transforms some of these catechins and leads, notably, to the formation of molecules such as theaflavins and thearubigins.

The sensory profile evolves accordingly.

Reducing all astringency to “a lot of tannins” therefore does not allow us to account for the real richness of the leaf and its transformations.

IX. Can we learn to appreciate astringency?

Yes—but appreciating does not mean you have to like all astringent cups.

At the beginning of discovering tea, we often spontaneously seek sweetness. Very easy, round, or aromatic infusions are immediately accessible.

With experience, the palate can begin to seek something else: length, tension, texture, the aromatic return after swallowing, the transformation of the sensation over the seconds.

A fine astringency can then become interesting.

It can structure the liquor, accentuate the sensation of freshness, or cause a return of salivation that prolongs the experience.

The goal is not to turn tasting into an exam.

It is enough to start by observing.

THE BREATH RITUAL

Recognizing astringency in three sips

Prepare a tea you already know.

First sip—the taste.
Focus your attention on what you taste immediately: sweetness, bitterness, possible acidity, intensity.

Second sip—the texture.
After swallowing, wait a few seconds. Pass your tongue against your cheeks and your gums. Observe if the mouth feels as supple as before.

Third sip—the return.
Do not drink again for about ten seconds. Observe what happens: persistent dryness, return of salivation, freshness, aromas that return, or the rapid disappearance of the sensation.

You have just moved from a tasting based solely on taste to an observation of the texture and evolution of the cup.

X. How to correct a cup that is too astringent?

You prepared a tea and the mouth feels completely dry?

Before changing tea, change the infusion.

Several adjustments can be tested separately.

1. Reduce the time

This is often the first trial to make. A shorter infusion limits extraction and can make the result significantly more balanced.

2. Slightly lower the temperature

This method is particularly useful for certain delicate green teas. You don’t need to go from very hot water to lukewarm water: a moderate adjustment can already transform the cup.

3. Check your dosage

A large amount of leaves in a small volume of water generally requires more precise timing.

A recipe designed for short infusions should not be left for several minutes without adjustment.

4. Observe your water

Water makes up the vast majority of your cup. Its mineral content influences extraction and sensory perception.

If a tea consistently tastes harsh despite your adjustments, trying a different water can be an instructive experience.

5. Change only one variable at a time

This is the most important piece of advice.

If you change the dosage, temperature, water, and time all at once, you may get a better cup, but you won’t know why.

Tea becomes much easier to understand when you approach it as a small, reproducible experiment.

◆ ◇ ◆

XI. A sensation that also tells the story of the leaf

Astringency reminds us of something essential: tasting tea is not solely about seeking aromas.

An infusion has an architecture.

It can be thick or light, supple or sharp, smooth or biting, fluid or clinging.

The aroma often makes you want to bring the cup to your lips. But texture is one of the things that determines what happens next.

This is also why two teas with relatively similar aromas can offer radically different experiences.

As you learn to identify these sensations, the way you choose and prepare tea evolves.

You no longer search only for:

“What does this tea taste like?”

You begin to ask:

“What does it do in the mouth?”

This second question opens up a large part of the vocabulary of tasting.

KEY TAKEAWAYS

Astringency in five points

1. Astringency and bitterness are not the same sensation.

2. It manifests notably as a sensation of dryness, friction, or tightening in the mouth.

3. Tea polyphenols and their interactions with saliva play a major role in its perception.

4. Temperature, duration, dosage, and water influence the result of the infusion.

5. Astringency is not necessarily a flaw: what matters is its balance with the rest of the cup.

XII. What astringency teaches us

A cup of tea is never just a list of aromas.

It has a temperature, a density, a texture, an attack, an evolution, and a finish.

Astringency belongs to this invisible geography of the mouth.

At first, it is sometimes perceived as an indistinct flaw: “this tea is too strong.”

Then comes the moment when you begin to recognize it.

You then understand that a cup can be bitter without being extremely astringent, astringent without being unpleasantly bitter, or possess just enough tension to bring the infusion to life.

This distinction may seem modest.

Yet it profoundly changes the way you taste.

Because learning about tea is not about memorizing complicated words. It is about gradually putting precise words to sensations we already had.

The next time a cup seems too “strong” to you, do not judge it immediately.

Listen to what it does to your mouth.

◆ ◇ ◆

CONTINUE THE JOURNEY

To better understand what transforms a leaf into a cup, continue reading in the Tsuru Collection with the chapters dedicated to temperature and steeping time, tea tasting, and caffeine.

Each step adds a new landmark: the leaf, the water, the molecules, and then the sensations.