Bloom
What is bloom in coffee?
The bloom is the first small pour of water in a brew, usually 2–3 times the weight of the coffee, followed by a 30–45 second pause. It lets carbon dioxide trapped in freshly roasted coffee escape so water can then extract the grounds evenly.
The fresher the coffee, the more it bubbles and swells during the bloom. Coffee that barely blooms is often stale. In espresso the equivalent step is called pre-infusion. Used in: V60, Chemex, Kalita Wave.