Beer drinkers don’t talk much about head (I called it “foam” in the headline to avoid unwanted google hits of a different nature), which is odd given how important a role it plays in our perception of beer. It is both a simple thing, but we are often murky on the details of why head forms, why some last longer and why some create lacing down the glass. I am no biochemist, and so the science aspects of beer head are above my pay grade. However, I do know a few things about what encourages and discourages good head, so I decided to jot a few down in my latest Beer 101 column (which you can read here).
A lasting head is what separates beer from all the lesser carbonated beverages, such as soda and champagne. Those drinks lack the residual proteins needed to keep the gas trapped on the surface of the beer. (By the way, head is simply a mixture of beer and carbon dioxide.) Head is important for aroma and the general attractive appearance of beer.
To a certain extent, amount of head is a personal preference, but there are some good rule of thumbs to go by. I like the two-finger rule – the head should be the width of two fingers. Anymore and the pub is trying to short change you on your pint (intentionally or not). Of course, that rule is affected by the shape of the glass, the style of beer being poured and many other factors. In general I prefer a little less head, but I want it to persist.
In the column I talk about what contributes to and detracts from getting decent head. First, it is a sign of beer health (too much and too little are bad signs). Second it is affected by glass cleanliness, glass shape, etchings or flaws in the glass, beer temperature, and the roughness of the pour. I then finish the article with some tips on how to pour to get the right amount of head.
Of course, the problem with an article on head (aside from the inevitable sophomoric jokes that ensue) is that a few tips really doesn’t do the subject much justice. There are simply too many factors that shape how much or little head is produced. At the end of the day, it really is just a matter of practice and experience. Which isn’t such a bad fate, as it means you just need to drink different kinds of beer to learn how each reacts. Life could be worse.