Glossary
Head retention
How long foam persists on a beer, determined largely by foam-positive proteins and hop iso-alpha-acids, and destroyed by fats and detergent residue.
Wheat and oats improve it because they contribute foam-positive protein. Hop acids stabilise foam, which is part of why heavily-hopped beer holds a head well. Lipids from grain or from a greasy glass collapse it, which is why a beer that had a good head in one glass can have none in another.
This is the mechanism behind the "beer-clean glass": a rinsed glass with detergent residue kills a head, and the same beer poured into a properly washed glass behaves entirely differently.
Related
- Lacing — The visible trace a retained head leaves.
- Beer-clean glass — The handling issue that most often destroys it.
More vocabulary
Astringency · Body · Chill haze · Ester · Hop burn · Lacing · Mouthfeel · Phenol
See every term on the glossary index.
Last reviewed 2026-08-16.
Evidence
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Lipid and detergent residue on glassware collapses beer foam on contact, which is why the same beer holds a head in one glass and not in another and why the trade distinguishes a "beer-clean" glass from a visibly clean one.
Backed by a source
Sources: Institute of Brewing & Distilling technical publications; Tasting Beer (2nd edition) — print
Head retention depends chiefly on foam-positive proteins — contributed particularly by wheat and oats — and on hop iso-alpha-acids, both of which stabilise the bubble film that lipids destroy.
Backed by a source
Sources: Beer: Tap into the Art and Science of Brewing — print; Brewing: Science and Practice — print