Foam is a friend, not an unwelcome guest taking up too much space in our glass. Today on Beer Notes we will discuss the head on your beer and why it is desirable.
Beer head, foam, kräusen or froth, all names for the bubbles at the top of your beer. This foam is produced by nucleation. One protein found in barley, largely responsible for the creation of bubbles is Lipid Transfer Protein 1 or LTP1. This protein doesn’t like water so it grabs hold of a CO2 or Nitrogen bubble and rises to the surface of your beer. LTP1 then coats the surface of the bubble and helps to create a head that is more stable. Other proteins in grains also contribute to the head on your beer. Temperature, detergent residue and the alcohol content also contribute to the production of these bubbles.
A thick capping of foam is essential. The foam carries the aromatics which contribute significantly to your taste and perception of flavor. The foam also adds to the creamy texture while drinking. Nitrogen produces smaller bubbles and “feels” more creamy. In addition, the head protects the beer from oxygen which degrades the flavor of the beer.
“If a beer is poured to the brim with no foam, all of those aromatics are just kind of going away,” said Neil Witte, the owner of Craft Quality Solutions, a Kansas City consulting firm focused on beer service. He generally recommends a one-inch collar of foam, though some highly carbonated beers, such as German weissbier, can be poured with a larger head.
The next time you pour your beer make sure it has a 1” layer of foam; you’ll be glad you did.