A curve, not a fade
The intuitive model of repeated steeping is a diminishing series: each infusion takes some of what is left, so each must be weaker than the one before it. Sessions do not behave that way, and anyone who has run a rolled oolong through eight steeps knows it — the second or third is unmistakably bigger than the first, and the most interesting part of the session frequently sits somewhere in the middle rather than at the start. The reason is that the first steep is not competing on equal terms with the ones that follow. It spends a large share of its time wetting dry, folded, sometimes compressed material rather than extracting from it, so its result reflects the outside of the leaf rather than the leaf. Only once the material is open does the tea show what it actually has. Recognising the session as a curve with a peak somewhere in it changes what you do about a disappointing first cup, which is usually nothing at all, and it stops a good tea being written off on the evidence of its least representative infusion.
The first steep is partly plumbing
Dry tea is a folded, water-repellent structure that water has to penetrate before it can dissolve anything from the interior, and how long that takes depends entirely on the form rather than on the quality. An open, unrolled leaf is wetted through in seconds. A needle-rolled leaf takes appreciably longer. A tightly rolled ball can take a minute or more, and a compressed chunk several. Throughout that period, extraction is happening only at the outer surfaces, so the liquor is both weaker and different in composition from what the same leaf gives once it has opened — it is not a dilute version of the later cups, it is a sample of a different part of the leaf. This is the single reason the first steep of a rolled tea underrepresents it, and it is why a rinse makes such a difference to what follows: a rinse is a wetting step that has been given a hygienic justification, and the wetting is what it is actually accomplishing.
Where the peak sits, and what moves it
Unrolled and open-leaf teas peak early, often on the first steep, because there is no opening phase to get through and the leaf is fully available immediately. Strip-rolled oolong and most whole-leaf black tea peak on the first or second. Ball-rolled oolong typically peaks on the second or third, which is exactly why the convention of a long opening steep exists and why a schedule that starts short and then drops shorter looks so strange until it is explained. Compressed dark tea peaks later still and can keep climbing through four or five infusions, and the same tea broken into smaller pieces peaks sooner. The variable is not quality, age or price but how long the material takes to open, which means the peak is predictable from the dry leaf before any water is boiled. Looking at the leaf and asking how long it will take to unfurl is a better guide to how to run the session than any category rule, and it takes no equipment.
The long tail, and what is in it
After the peak the liquor changes character as well as intensity, and the change is more interesting than the decline. The aromatic top notes go first, because they are volatile and are also the fraction that comes out fastest, so a late infusion of a fragrant tea smells much less than an early one. What remains for the later steeps is sweetness, mineral texture and body — the slow-dissolving fraction that was never going to appear early. A well-made dark tea or a good rock oolong can run a long way into this, and those late cups are not failures but a different part of the same tea, often the part regular drinkers value most. This is also the part most frequently thrown away by people who stop when the colour lightens, which is a decision made on the wrong evidence entirely: colour tracks a fraction that leaves early, so it drops away well before the body does.
Reading the arc as information
The shape of a session tells you things that no single cup can. A tea that peaks hard on the first steep and drops sharply afterwards is usually made of small or broken material regardless of what the packaging says about whole leaf. One that climbs slowly and then holds a long plateau has substantial, intact leaf and has probably been stored well. A session that is intensely aromatic for two infusions and then empty by the fourth has usually been scented rather than being naturally fragrant, or has lost its volatiles to poor storage. And a tea whose second steep is markedly harsher than its first was over-steeped on the second — not by the schedule but by the person following it, since the leaf is now open and extracting faster than it was. That last one is the commonest reading error of all, and it is a timing correction rather than evidence of a fault in the tea.
Why a schedule is a starting point
Every authored schedule in this catalogue describes a curve that someone expected, and the leaf in front of you may have a different one. Compression, storage conditions, how finely a cake was broken, how much dust came with it and how completely the previous steep was drained all move the peak around, sometimes by two or three infusions. The useful habit is to hold the schedule for the first two steeps, which establishes a reference, and then start adjusting from what the cup is actually telling you: if the third is bigger than the second, hold the time rather than extending it; if it has dropped away sharply, extend more than the schedule suggests rather than less. Following a printed sequence past the point where it stopped matching the tea is one of the most reliable ways to get a bad session out of a good tea, and it happens because the schedule feels like an authority rather than a hypothesis.
The one habit that flattens every arc
Leaving liquor in the vessel. Whatever stays behind carries on extracting between steeps, at whatever temperature the vessel is holding, and joins the next infusion already over-extracted and already carrying the later fraction. The effect compounds across a session and it flattens the curve in a specific and recognisable way: the peak arrives lower than it should, the harshness arrives sooner, and the tail is noticeably shorter. Nothing else in technique costs so much for so little effort to correct, and the correction is simply to pour for another second or two and to tip the vessel further than feels necessary. It is why every parameter set in this catalogue describing a multi-infusion method says to pour to the last drop, and why vessels that cannot be emptied completely are a poor choice for short-steep brewing however good they are in other respects.