The Science and Art of Beer Foam
What is Beer Foam?
Beer foam, also known as the head, is the frothy layer that forms at the top of a freshly poured beer. This creamy crown is created by bubbles of carbon dioxide gas rising to the surface, where proteins from the malt and hops form a stable structure around them.
Characteristics of Quality Foam
- Density: Should be creamy and tight, not bubbly or loose
- Retention: Should last several minutes without dissipating
- Lacing: Leaves patterns (lace) on the glass as the beer is consumed
- Color: Varies from bright white to tan depending on beer style
- Height: Typically 1-2 inches, though varies by beer type
Factors Affecting Foam Quality
Several elements influence beer foam formation and retention:
- Protein content from malted barley
- Hop iso-alpha acids
- Carbonation level
- Glass cleanliness (dirty glasses kill foam)
- Pouring technique
- Beer temperature
- Alcohol content (higher alcohol can reduce foam)