Why weigh everything

A coffee scoop measures volume. Coffee, unfortunately, is roasted, sold, and brewed by mass — and the two drift apart the moment the roast changes. Dark-roasted beans puff up and shed water in the roaster, so a level tablespoon of a dark roast can weigh 30% less than the same spoon of a dense light roast. Same scoop, wildly different dose.

That drift is why scooped coffee feels inconsistent even when you do everything else identically. A two-gram swing on a 15 g dose moves your ratio by more than a full point — the difference between a balanced cup and a thin one, before you have touched the kettle.