Steam

Although steam is too hot for brewing coffee, the power of steam is used in certain coffee brewing methods to create pressure. Pressure in turn improves the extraction.

Steam is the technical term for water vapor, the gaseous phase of water, which is formed when water boils. Water vapor cannot be seen, though in common language it is often used to refer to the visible mist of water droplets formed as this water vapor condenses in the presence of cooler air. Strictly speaking, in terms of the chemistry and physics, true steam is invisible.

Two examples of brewing methods that use pressure are Moka pot, and steam espresso machines.