What Tannins Do to Your Tea (And Why 'Astringent' Is Not the Same as 'Bitter')
There is a word that gets used for tea more than any other, and it is usually used wrong. People say their tea is "tannic" when they mean it is bitter, and they say their tea is "bitter" when they mean it is drying and sharp. Those are two different things, they come from two different parts of the plant, and they get fixed in two different ways.
Here is the difference, what is actually in your cup, and how to take the edge off.
The dry feeling is not a taste
Start with the mouth.
Bitterness is a taste. It registers on your tongue the same way sweet or sour does. You can taste it with your eyes closed, and you can taste it in a tea that has no sharpness in it at all.
Astringency is a texture. It is the drying, puckering, tightening feeling across the sides of your mouth and the roof of your mouth, the feeling of your cheeks pulling in slightly. It is not a taste. If you drink something astringent and hold it in your mouth, you will struggle to name it as anything except "dry."
The chemical that causes the drying is called a tannin. Strictly speaking, tannin is a class of compound — in tea, a group of polyphenols, mostly a family of molecules called catechins. When they bind to the proteins in your saliva, they pull the proteins together and everything gets tighter. That is the same basic mechanism that makes an unripe persimmon feel chalky in your mouth.
Tea is one of the richest sources of these compounds in the plant world. Coffee has its own version of the problem, which we cover in why coffee tastes sour or bitter.
Where the tannin actually comes from
This is the part worth knowing: tannins are brewed out of the leaf. They are not added, and they are not mostly in the dust.
They live in the leaf's cell walls, bound up with the plant's other structural material. Hot water over a leaf breaks those walls down and pulls the polyphenols into the cup. Which means the amount of tannin in your tea is decided almost entirely by three things:
How long you steep. More time, more extraction. This is the big one. We wrote about the mechanics in why oversteeped tea tastes harsh.
How hot the water is. Hotter water extracts faster and pulls more of the compound families you do not want in large amounts.
How broken up the leaf is. Whole leaf takes longer to give up its contents. Broken leaf, dust, and fannings — the fine material that settles at the bottom of a teabag or a tin — release far more tannin in a short time, which is why dust tea can taste sharp in two minutes while the same plant in whole-leaf form is fine at four.
That last point is why a good loose-leaf tea and a cheap teabag of fannings are not the same drink, and it is why the leaf-size terms on a label matter. We covered what is actually printed on a tea bag in what the terms on your tea bag actually mean.
Why green tea is more astringent than black tea
Counterintuitive, but true. Black tea is more oxidized than green tea, and it has more total polyphenol content by weight. It is also, in a normal cup, much less astringent.
Here is why. When a tea leaf oxidizes, the catechins — the astringent ones — react with each other and convert into different compounds called theaflavins and thearubigins. Those give black tea its color and its body. They are also far less binding, so they do not make your mouth dry.
Green tea is not oxidized. It is heated quickly after picking to stop the reaction, which preserves the catechins exactly as they were in the leaf. So the astringency stays intact, and green tea is the more tannic drink, even though black tea has more polyphenols on paper.
That is also why black tea and milk have been a tradition for so long. Milk proteins bind tannins, which is why adding milk to tea takes the edge off. We wrote about the whole argument in how to brew a proper British cup of tea, and about the chemistry in does milk change how black tea tastes — milk does more than dilute.
We are not against milk. We are against putting milk in before you have tasted something.
Not every sharp tea is tannic
Here is the part that trips people up, and it matters for the teas we sell.
Hibiscus is not tannic. The drying, puckering feeling in hibiscus comes from its acidity, not from tea polyphenols. Hibiscus is deep red because of anthocyanins, and it is tart the way lemon is tart. That is a different sensation from tannin, even though the two can feel similar on the tongue.
Rooibos is not tannic either, and it is naturally sweet. Rooibos has essentially no tannins at all. Its sweetness comes from a compound called aspalathin, which tastes sweet all on its own. That is why rooibos is the base of so many caffeine-free blends that people drink as a treat rather than as a medicine.
Rosehips are tart, not tannic — and they carry their own polyphenols, but not the binding kind.
So a cup can be sharp, drying, and sweet all at once, and none of those three words mean the same thing. Getting that vocabulary straight is most of what it takes to brew tea well. We touched on the difference between a tea and a tisane in tea, tisane, and herbal infusion.
How this applies to what we sell
Our Jasmine is a green tea base, so it behaves like a green tea: moderate astringency, which is exactly why our brewing spec says 170 to 180°F for 2 to 3 minutes, and why the multi-steep method works so well on it. The first 30 seconds pulls aroma and sweetness, and the tannins are still locked in the leaf. We wrote the full method in how to brew jasmine green tea.
Our Hibiscus Berry blend — hibiscus, rosehips, orange peel, and rooibos, with blueberry, passionfruit, and mango flavoring — scores low on astringency and high on sweetness and body. That means you can give it boiling water and five to ten minutes and it will not turn sharp, which you do not get with a tannic leaf. The spec is in how to brew hibiscus berry tea, and the cold-brew version holds the sweetness even better.
Our Mango Treat and Peach Paradise are fruit-forward herbal blends with no tea leaf in them at all, so there are no tea tannins to over-extract. Mango Treat — mango, hibiscus, rosehips — is naturally sweet enough that you do not reach for honey. Peach Paradise gets its sweetness from dried peach and cranberry with rose. Both are 0 mg caffeine. The methods are in how to brew Mango Treat herbal tea and how to brew Peach Paradise herbal tea.
If your tea tastes sharp, here is the order of fixes
Work down this list and stop when the cup tastes right.
Shorten the steep. This is the single most effective change. If you steeped for four minutes and it is sharp, try three. Then two and a half. We have more on the mechanics in what second steeping does to your tea.
Drop the temperature. A few degrees less means less extraction of the compounds you do not want. If you do not have a thermometer, how to brew tea without a thermometer has the cold-start method, and the full range is in water temperature by tea type.
Use less leaf. More leaf in the same water means a lower concentration of anything you extract. If you are using a rounded teaspoon for a large mug, try a level one and a half.
Take the leaf out on time. Do not just leave a mug of tea sitting on the counter to steep itself into a state. This is the most common cause of a sharp cup, and it is worth one sentence because we have to say it constantly: a timer is the difference between tea and a mistake.
Add milk, if it is black tea. The proteins bind the tannin and pull the drying right down. Just do not add it before you have decided you like the cup.
One more thing worth knowing
Tea tannins bind non-heme iron, which is the iron in plants and the iron in most supplements, and they bind it well enough that drinking tea with a meal reduces how much of that iron you absorb. This is why nutrition guidance in a lot of places suggests drinking tea between meals rather than with them.
It is not a reason to give up tea. It is a reason to stop treating the last three hours of the afternoon as a coffee refill schedule. We wrote about that in how to choose between tea and coffee in the afternoon and in what to drink when cutting back on caffeine.
Try it this week
Brew one tea two ways. Same leaf, same water, same leaf-to-water ratio. One steep for two minutes, one for five. Taste them side by side, and pay attention to the difference between the bitter on the tongue and the drying across the mouth.
The five-minute cup will be more bitter. The two-minute cup will be more astringent, because the tannin is the first thing to arrive and it keeps coming.
Then the third cup, at seven minutes, where you have let the leaf sit in water that has cooled to warm. That is the cup most people throw away, and it is usually the smoothest one of the three.
P.S. If you are new to loose-leaf tea, the fastest way in is a tea that will not punish you, which is exactly how we would start. How to brew hibiscus berry tea and hibiscus iced tea are the two we send people to first, and neither of them needs a thermometer or a scale.
Steep slow.
Sip slow.
— Seraphina