What is the role of the coffee "bloom" during brewing?

The role of the coffee "bloom" during brewing is primarily to allow gases to escape, which enhances the extraction process. When coffee grounds are initially saturated with water, carbon dioxide that has built up during the roasting process is released. This phenomenon, known as blooming, creates a formation of frothy bubbles on the surface of the coffee grounds.

This release of gas is crucial because it helps to improve extraction by making it easier for water to permeate the coffee grounds more efficiently. If the gases are not allowed to escape, they can create a barrier that prevents water from fully saturating the grounds, leading to uneven extraction and a less flavorful cup of coffee. Hence, blooming is an essential step in various brewing methods as it optimizes flavor extraction and ensures that the coffee is brewed uniformly and effectively.