Cold brew

Cold brew is coffee made by steeping grounds in cold or room-temperature water for a long time, typically 12 to 24 hours, then filtering out the grounds. It is an immersion method: time replaces heat as the thing that drives extraction.

Why it matters: brewing without heat changes what dissolves. Many of the acids and aromatic compounds that hot water pulls out quickly come across more slowly or barely at all in cold water, so cold brew tastes smooth, sweet, and low in perceived acidity, with a heavier body. People who find hot coffee too sharp on the stomach often prefer it. Note that “low acid” is about taste and not a large change in pH.

How it shows up: most recipes make a concentrate, often around a 1:5 to 1:8 coffee-to-water ratio, which you dilute with water, milk, or ice to taste. Use a coarse grind, similar to French press, to keep the long steep from over-extracting. Do not confuse it with flash brew, which is hot-brewed straight onto ice. If yours comes out thin, see why your cold brew is weak.