Water Is the Ingredient You Keep Ignoring

A brewed cup is somewhere north of ninety-eight percent water. We obsess over the two percent and pour municipal tap water over it without a second thought.

Minerals in water are what actually bind to and carry flavor compounds out of the grounds. Too soft and the cup reads flat and hollow, like someone described coffee to you instead of making it. Too hard and the magnesium and calcium fight the extraction, muting acidity and leaving scale in your machine.

You do not need a laboratory. Filtered water with a moderate mineral content, somewhere near 150 parts per million of total dissolved solids, will outperform both distilled water and whatever comes out of your kitchen faucet.