A bamboo strainer breaks every clump, so the froth lifts even and pale-green — never grainy at the rim.
Around 70 °C keeps the catechins sweet; boiling water scorches the leaf and turns the bowl bitter.
A brisk wrist tracing the letter M for forty seconds folds air through the tea instead of just stirring it.
The foam settles fast — past a minute and a half the surface flattens, the aroma fades, the bowl forgets.