Dry hopping

Dry hopping means adding hops to beer that is fermenting or already finished, rather than during the boil, so their aromatic oils infuse into the beer without the heat that would otherwise convert hop compounds into bitterness. It is the technique behind the big, juicy hop aroma found in many modern pale ales and IPAs, layered on top of whatever bitterness was already set during the boil.

Brewers typically add hops either partway through active fermentation or after it settles down, sometimes in stages, and leave them in contact with the beer for several days before packaging. Hops can be added loose, in a mesh bag, or through a hop spider that makes straining easier later, and contact time along with hop quantity both shape how intense the final aroma comes through.

A common mistake is dry hopping for too long, which can pull grassy or vegetal notes from the hop matter alongside the desired aroma, or dry hopping too early before fermentation has calmed down, which can blow some aroma compounds out through the airlock along with escaping CO2. Storing hops properly beforehand also matters, since stale or warm-stored hops lose aromatic potency well before they lose bitterness.