It is one thing to be a beerhead, and quite another to have a beer head. A beer’s head is the layer of foam on top of the liquid, visible when the beer is poured into a glass or a mug. The head is formed by the bubbles of carbon dioxide in the beer rising to the surface and being held together with surface tension. Fermentation produces natural carbon dioxide, but many beermakers also add is to their products specifically to produce a good head.
But I can remember working in countless restaurants, and being taught to pour the beer down the side of the glass in order to avoid a head. And many customers who receive a beer with a thick head will send it back, believing it to be a bad pour. To be fair, I have seen some ridiculous heads, taking up half or more of the volume of the glass, and no one wants that. But in terms of a normal-sized head, is it a good thing or a bad thing?
For beer aficionados, a good head is a good thing. The thickness of the head depends on the particular beer, and the shape and cleanliness of the glass, as oil in a glass (even tiny amounts of skin oil) will quickly dissipate a the foam on a head. The fact is that the carbon dioxide in a good head carries with it intense, complex aromas from the beer that otherwise might be lost to the nose and the palate. As an example, a good India Pale Ale (IPA) will have a nice, bitter flavor, but if you sniff the foam and drink it with a head, you will also detect undertones of citrus fruit and pine needles. So in order to enjoy a beer to its full potential, you should let it develop a natural head on the pour.
What is a natural head? It all depends on the particular beer that you are drinking. Some beers, for example the Chinese Harbin beer than I am drinking as I write this, have a thin, white, sudsy head. Others, like Guinness Stout, have a thick, creamy, silky head. Still others, such as Brewdog Hardcore IPA have an orangish, medium-bodied head that seems to glide across the lips as easily as the beer itself.
So next time you pour a beer, do not be afraid to let it develop its own natural head, be it thick or thin. Hold the head up to your nose and take a few deep whiffs, noticing the complex aromas that you detect. And as you drink it, allow the head to pass your lips and coat your tongue. You will notice even more flavor and complexities than ever before.