Bavarian lager hops grown in Germany, used to make Samuel Adams Boston Lager. Bavaria's Hallertau region has only 400 acres of hop growing land with the perfect soil and climate for growing Mittelfrueh hops. The foam at the top of a beer. The head is the protein which is pushed out of suspension by the bubbles. The flower of a perennial vine, and one of the four ingredients of beer.
Hops are the universal spice of beer.
Hops, like grapes used in wine, are varietal. Some varieties contribute mainly bitterness, while others are prized for their fine aromas.