It looks good and delicious everytime! A beer with a nice thick foam head on top of it. The sight of this will make you want to have a beer as well. The question that’s often asked is, why does beer have a foam head and what is the purpose of a foam head?
A foam head covers beer like a blanket. It protects the beer. The foam head functions as a lid that prevents the carbon dioxide to quickly evaporate from the beer in the glass. Without the protective foam head, the tingly fresh flavour of beer disappears quite fast.
That same foam head ensures that your beer is protected from air. It is almost like an air tight cover over your beer, preventing it from oxidising too quickly. Oxygen can rapidly affect the flavour of beer. Oxidised beer just doesn’t taste well, the once refreshing aromas that were in your beer has changed into a dull and flat flavoured beer.
The sturdiness of a foam head is of great importance. You would like the white blanket over your beer to remain as long as possible. This, of course, is measurable. Experts measure this with the half-life system. This is actually pretty simple. The time is measured in which the foam head halves in volume. If the time is 110 seconds or more, than you have a nice thick foam head protecting your beer.