Alkalinity

What it is and what sets it apart: Alkalinity (often as KH / ppm CaCO₃) is not pH and not total hardness (GH). It’s the cushion that neutralizes coffee acids—tuned via water recipes or filters.

How it’s used or measured: Measure with a KH kit or compute from recipe salts. Typical aim: moderate alkalinity (e.g. ~40–70 ppm CaCO₃). Compare with GH—they can diverge.

Flavours and cup impact: Low alkalinity: brighter/sharper acidity; high: rounder or muted cup. Benefit: know if “acid” is bean or water.

Technical notes: Labs report CaCO₃. KH ≈ carbonate alkalinity for most home brew waters.

Common mistakes: Confusing alkalinity with pH or GH. Raising buffer until the cup is flat. Using pH alone as proxy.