Judging Chai by Its Colour Is a Habit That Misleads

Most people decide a chai is ready by looking at it. Colour is a fast signal and an unreliable one, because the things that darken a pan are not the things that strengthen it.

Leaf grade dominates the colour

Small, hard-processed leaf gives up colouring compounds very quickly, so a modest quantity of dust-grade CTC produces a deep red-brown within a minute or two.

Larger orthodox leaf colours far more slowly at the same strength, which makes a properly brewed pot look weak by comparison at the moment it is actually ready.

Judging both by the same visual standard therefore over-brews one and under-brews the other, in opposite directions.

Milk changes the reading entirely

Once milk goes in, the colour is a function of the milk proportion at least as much as the tea. A milkier cup is lighter regardless of how strong the decoction was.

Cooks who wait for a familiar shade after adding milk will boil far longer in a milk-heavy cup, which changes the milk more than it changes the tea.

Fat content shifts it again, since full-cream milk lightens a cup more than a skimmed one at the same volume.

Colour and strength come apart with time

Reused leaf, long standing and prolonged heat all continue adding colour after the aromatic extraction has finished, so appearance keeps improving while the cup does not.

This is exactly the failure that makes second-boil chai look convincing, and it operates in a first boil too once it has gone on too long.

A dark pan is therefore evidence of either strength or over-extraction, and colour alone cannot distinguish them.

Better signals are available

Smell is the most useful check. A pot at the right point smells of tea and spice together; one that has gone too far smells increasingly of boiled milk alone.

The behaviour of the boil helps as well, since a decoction thickens slightly and its foam changes character as extraction progresses.

A taste from a spoon, unsweetened, settles it in a second and is the only method that measures the thing you actually care about.

Calibrating your eye rather than abandoning it

Colour is not useless; it is uncalibrated. Anyone using one leaf and one milk consistently can learn what the right shade looks like for that combination.

The rule fails at the moment the leaf, the milk or the ratio changes, which is precisely when a cook is most likely to be relying on it.

Treating a change of any ingredient as a reason to taste rather than look is enough to remove most of the error.