Bitterness
One of the five basic tastes, and the one people most want less of. A little is structure and a lot is a brewing error, so the useful question is almost never whether a tea is bitter but whether it was made bitter.
- Sensed as
- taste
- Compounds
- caffeine, and the galloylated catechins EGCG and ECG
- Rises with
- hotter water, longer steeps, a cooling cup
- Falls with
- cooler water, shorter steeps, roasting, shading in the field
What it is
A taste, registered while the liquor is in your mouth and largely gone once you swallow. It sits at the back of the tongue for most people, though not because bitterness lives there. In tea it usually arrives with astringency, which is why the two get bundled into one complaint.
Where it comes from
Two families of compound, working together. Caffeine is the one people expect. The larger contribution comes from the galloylated catechins, EGCG and ECG, which are strongly bitter on their own and are made more so by the caffeine sitting beside them. Both extract faster in hotter water, which is why temperature is the first thing to change.
Which teas show it
Highest in unshaded green teas brewed too hot, in young sheng puer and in high-caffeine black teas pushed past their time. Shaded Japanese greens are lower despite their caffeine, because shading pushes the leaf toward amino acids and away from catechins. Roasting lowers it further, which is part of why a heavily roasted oolong reads as sweet.
How to turn it down
Drop the water temperature before touching anything else. Green tea at 80 degrees rather than boiling is often the whole fix. Then shorten the steep. If a tea is still bitter after both, use more leaf and less time rather than less leaf and more, because a short heavy steep pulls the aromatics before it pulls the catechins. And drink it while it is hot: bitterness genuinely increases as a cup cools.
How to turn it up
Rarely the goal, but hotter water and a longer steep will do it. Some drinkers want the bitterness of a young sheng or a strong Assam as a counterweight to milk or sugar.
What it gets confused with
Astringency, which is a texture rather than a taste and arrives after the swallow instead of during it. Bitterness fades; astringency builds. If you are unsure, wait thirty seconds. Also confused with the sharpness of a tea brewed with very soft water, which reads as thin and edgy without being bitter at all.
What people get wrong
Assuming a cooling cup is telling you the truth about the leaf. Detection thresholds for caffeine and the other methylxanthines are measurably lower at fifteen degrees than at twenty five or forty five, so the same cup genuinely gets more bitter as it cools. A tea that was balanced hot and harsh cold was not badly made. The other mistake is blaming caffeine for all of it. The catechins do more of the work, which is why a decaffeinated tea can still be punishingly bitter.
If this is your problem
Sources
- The main contributors to bitterness in tea infusion are the catechins ECG and EGCG, with caffeine enhancing them. Narukawa et al., 'Evaluation of the bitterness of green tea catechins by a cell-based assay with the human bitter taste receptor hTAS2R39', Biochem. Biophys. Res. Commun. (2011)
- Bitter detection thresholds are lower at 15 °C than at 25 °C or 45 °C, so a cup gets more bitter as it cools. 'Theacrine stabilizes the TAS2R14-EGCG complex to potentiate bitter taste signaling in a temperature-dependent manner', Food Chemistry (2026)