Tea Education
Tea Tannins Explained: The Source of Astringency
That dry, puckering feeling from over-steeped tea comes from tannins. Here's what they are and how to keep them in check.
Key takeaways
- Tannins (mainly catechins in tea) are plant compounds responsible for astringency, that dry, puckering feeling.
- Longer steeps, hotter water, and more leaf all extract more tannin, not just more flavor.
- A little tannin gives tea structure and body; too much makes it taste harsh and bitter.
What tannins actually are
In tea, the term 'tannin' is used loosely to describe a group of polyphenols, mainly catechins in green tea and their oxidized cousins, theaflavins and thearubigins, in black tea. Chemically they're related to the tannins found in red wine and unripe fruit.
They're responsible for the dry, mouth-puckering sensation called astringency — the feeling, not really a taste, that makes your tongue feel slightly rough after a strong cup.
Recommended products
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The Tea Book: Beginner Guide
An illustrated guide to tea origins, processing and brewing method.
Why we recommend it: A good reference to keep next to the kettle while your palate develops.
Single-origin loose-leaf tea, 3.5 oz
A 100 g pouch of single-origin leaf with harvest and region on the label.
Why we recommend it: One good tea, drunk often, teaches more than twelve mystery pouches.
Why over-steeped tea tastes harsh
Tannins extract more slowly than the compounds responsible for aroma and sweetness, so a short steep captures mostly the pleasant notes. Leave the leaves in too long, brew too hot, or use too much leaf, and tannins flood the cup, tipping it from balanced to bitter and drying.
Controlling tannin in your cup
The good news is tannin extraction is very controllable once you know what drives it.
- Lower the water temperature for delicate teas like green and white
- Shorten the steep time rather than adding more leaf to compensate for weakness
- Remove the leaves or infuser once the steep is done — don't let them sit
- Add a splash of milk, which binds to some tannins and softens the dry feeling
Also worth having
Variable-temperature gooseneck kettle
Electric gooseneck kettle with presets from 160°F to boiling and a hold-temp setting.
Why we recommend it: Green and white tea scorch above 180°F — presets take the guesswork out of every steep.
Tannins aren't all bad
A moderate amount of tannin gives tea its structure and 'grip' — the difference between a thin, watery cup and one with real body. The goal isn't to eliminate tannin, just to keep it in balance with sweetness and aroma.
Recommended products to get started
Beginner Green Tea Sampler
Sencha, gyokuro, dragon well and gunpowder in single-session pouches.
Why we recommend it: The cheapest way to find out which green tea style you actually like.
Airtight opaque tea tin
Double-lid steel tin that blocks light, air and moisture.
Why we recommend it: Light and oxygen stale leaf faster than anything else in your kitchen.
Frequently asked questions
- Do tannins cause tea stains on cups and teeth?
- Yes, tannins are largely responsible for the brownish stains tea can leave on mugs and teeth over time, similar to how red wine stains a glass.
- Does milk really reduce astringency?
- Many people find it does — the proteins in milk bind to some tannins, which is part of why milky black teas taste smoother than the same tea brewed strong and black.
- Are tannins the same as caffeine?
- No, they're entirely different compounds. Tannins affect texture and astringency, while caffeine is the stimulant. A tea can be high in one and moderate in the other.
Related reading
The Six Types of Tea Explained
White, green, yellow, oolong, black and dark tea all come from one plant. Oxidation explains the rest.
7 min read
Tea Origins: How Region Shapes Flavor
China, Japan, India, Taiwan and Sri Lanka each produce a recognizable style. Knowing which helps you shop with confidence.
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Tea Flavor Profiles: Building Your Vocabulary
Words like brisk, malty, umami and astringent are useful, not pretentious. Here is what each actually describes.
6 min readMore in Tea Education, browse all tea guides, or use the tea converter to scale this recipe to your teapot.