Temperature & your kettle

Temperature is an honest variable: it does one thing, predictably. Hotter water extracts faster — every compound dissolves more readily — and it slightly favours the heavy, bitter compounds that arrive late in a brew. Cooler water extracts slower and leaves more of that tail behind. That is nearly the whole story; there is no temperature at which brewing water burns coffee.

Boiling water is not an act of violence. Dense light roasts often need 94–100°C to extract fully, and brewing them straight off the boil is standard practice among people who win competitions. The old fear of boiling water comes from dark-roast days.