Taste is a much smaller category than flavour
The word taste in ordinary use covers everything a mouthful of tea produces, and it is worth reserving it for the narrow thing: the small set of qualities registered on the tongue itself. That set is conventionally sweet, bitter, sour, salty and umami. Everything else in the experience of tea belongs to two other categories — aroma, which is smell and supplies most of what people call flavour, and mouthfeel, which is touch and includes astringency, body and texture. Keeping the three apart is the whole basis of useful tasting, because they have different causes and different remedies. A cup that is too bitter and a cup that is too drying are two different problems, and a cup that is aromatically flat is a third. Sorting first and describing second is the order that works. The conventional list of five is itself a simplification of a longer scientific argument, and other qualities have been proposed as basic tastes over the years. For describing tea the five are more than adequate, because four of them are prominent and the fifth is contested in this context anyway. What matters for a taster is not the exact length of the list but the discipline of asking, for each thing noticed in a cup, whether it was tasted, smelled or felt. Almost every confused tasting note in circulation is a note that never asked.
Bitterness
The most prominent taste in tea and the most misunderstood, because two quite different groups of compounds contribute to it. Caffeine, a purine alkaloid, is intensely bitter in isolation and is present in every true tea. The catechins — the flavan-3-ols that dominate the polyphenol fraction of green tea — are bitter as well as astringent, and the galloylated ones are more so. Since caffeine and catechins are both highly water-soluble and both extract readily, bitterness in a cup is nearly always a combination rather than one compound acting alone, and the balance between them shifts with temperature and with how far oxidation had proceeded before firing. Bitterness is also not automatically a defect: young sheng pu-erh from Bulang is aggressively bitter by design, matcha’s bitterness is structural, and Dan Cong is deliberately brewed close to its bitter edge because that is where its aroma sits. Bitterness also changes across a session in a way worth noticing. It is prominent early, because the compounds carrying it are among the fastest to dissolve, and later infusions of the same leaf are usually markedly less bitter and more sweet — which is why a tea judged on its first steep alone is being judged at its harshest moment. Anyone finding a tea too bitter should therefore try the second infusion before drawing a conclusion, since the difference between the two is frequently larger than the difference between two temperatures.
Sweetness, which is mostly not sugar
TeaHQ's own reading of well-attested general knowledge, with no single source behind it.
Tea contains only small quantities of simple sugars, so the sweetness a good tea shows is largely constructed from other things. Free amino acids, theanine most abundantly among them, read as a soft sweetness alongside their savoury quality. Some of the perception is contrast: remove or reduce bitterness and astringency and the remaining impression reads sweeter, which is why a cooler steep of a shaded green tea tastes sweet without anything sweet having been added. And a substantial share is aromatic, arriving through the nose rather than the tongue — the honeyed, malty and dried-fruit notes of a black tea or an aged white are smelled and attributed to taste. This is why sweetness in tea is so responsive to brewing: it is an emergent property of a balance rather than a quantity of one ingredient. There is a fourth source that experienced drinkers rate above all the others, which is sweetness that arrives after swallowing rather than during the sip. Chinese tea vocabulary names it directly as a returning sweetness, and it is treated as an evaluative criterion in its own right rather than as part of the taste of the liquor. Because it depends on a sequence rather than on a level, it is invisible to anyone who does not pause after swallowing, and it is the single most commonly missed dimension in tea tasting.
Sourness
Present at low levels in most tea from organic acids in the leaf, and normally a background rather than a feature. It becomes noticeable in three situations, each of which is diagnostic. A lightly oxidised, unroasted oolong that has taken up atmospheric moisture in storage turns sour, and so does a roasted oolong that has gone too long without re-firing — this is the single most common storage fault with a sour signature. Some dark and post-fermented teas carry a genuine acidity from microbial activity, which is part of their character rather than a fault. And a few teas are deliberately sour-adjacent: certain aged whites and some Liu Bao show a plum-like acidity that drinkers value. Sourness that appears in a tea that did not have it before is almost always a storage message rather than a brewing one. Brewing can produce a mild sourness of its own in teas that had none. A very long cold steep, or hot tea left standing for hours, will develop a flat acidity, and lemon or other additions obviously supply it directly. What distinguishes a brewing sourness from a storage one is that the first appears only under a particular preparation and the second is present in every cup and often detectable in the dry leaf. Establishing which you have takes a single differently brewed cup.
Saltiness, and how honest to be about it
TeaHQ's own reading of well-attested general knowledge, with no single source behind it.
The rarest of the five in tea and the most likely to be over-claimed. Tasting notes occasionally describe a saline or briny quality — in some deep-steamed Japanese greens, in gyokuro, in certain mineral-heavy rock teas — and it is worth being careful about what is being reported. A genuine sodium-driven saltiness is not something the tea catalogue has evidence for, and the more plausible readings are that the impression comes from the marine aromatics of shaded and steamed leaf, from mineral content in the water, or from an interaction with the savoury umami character rather than from salt. TeaHQ records marine as an aroma descriptor and does not record saltiness as a sensory axis, which is a deliberate decision rather than an omission: a descriptor that is reported rarely and explained uncertainly does not earn a place in a controlled vocabulary. The water is worth eliminating before attributing a saline impression to the leaf. Mineral content varies enormously between supplies and between bottled waters, and a water with a noticeable mineral character contributes it to every tea brewed with it — which is a common and under-diagnosed source of impressions attributed to particular teas. Anyone who finds several unrelated teas sharing a mineral or briny edge is probably describing their water, and brewing one of them with a different water settles the question in ten minutes.
Umami, which tea has more of than almost any other drink
The savoury, brothy, mouth-filling quality associated with glutamate and, in tea, with the free amino acids generally — theanine most abundantly. It is the defining character of shaded Japanese teas, where the agronomy is arranged specifically to favour it, and it is present to varying degrees across green tea, in some white teas and in the first infusions of a good oolong. Umami is also the quality most sensitive to brewing temperature, because the amino acids extract readily at low temperatures while the bitter and astringent fractions gain proportionally more from heat. That single asymmetry is the reason gyokuro is brewed at temperatures that would seem absurdly low for any other tea: the low temperature is not gentleness, it is selection. Umami is what is being selected for. Matcha and koicha are the extreme expression of it, and for a structural reason rather than a chemical one: the leaf is suspended rather than infused, so nothing is left behind in a filter and the whole amino acid content of the powder is delivered. That is why koicha is so thick and so savoury, and why it reads as a different kind of drink from even a very good gyokuro. The same fact explains why a poor matcha is unpleasant in a way a poor sencha is not, since the bitterness is delivered as completely as the sweetness.
Why the five never arrive separately
The tastes interact, and the interactions are as important as the components. Sweetness suppresses the perception of bitterness and bitterness suppresses the perception of sweetness, so a tea with more amino acids reads as less bitter at the same caffeine level. Umami and sweetness reinforce each other. Astringency, which is not a taste at all, sharpens the impression of bitterness because both arrive at once and the mouth does not naturally separate them. This is why a single-compound account of any tea is misleading: what a cup tastes like is a ratio and a sequence, not an inventory. It is also why brewing changes flavour so dramatically without changing the leaf. Every brewing decision is a decision about which fractions arrive in what proportion, and the tongue reports the balance rather than the contents. Temperature is the other variable that changes what the tongue reports without changing the liquid. The same tea tastes noticeably different hot, warm and cool — bitterness generally reads as less prominent as a drink cools, sweetness as more — which is why professional evaluation standardises the temperature at which liquors are assessed and why letting a cup cool a little is such a reliable way to find sweetness in a tea that seemed harsh. Tasting the same cup at three temperatures is a free and unusually informative exercise.