A Craft Beer & Brewing reader recently asked us the following question:
My beer has a nice layer of foam but it fades fast. What are some things I can do to improve head retention?
The fact that you start with a good head of foam indicates that you have a good carbonation level, but other things may be reducing its longevity. Head retention in beer is a combination of several factors, including your selection of malts, hopping rates, brewing techniques, and even glassware. Here are a few ways you can improve your head retention.
First, take a close look at your malt bill. Proteins and dextrins play a major role in head retention, and high-protein malts such as crystal, wheat, flaked barley, and Carafoam can improve the head retention. Think of an Irish stout, which has a nice white head that lasts forever. Proteins from a healthy dose of flaked barley in the grain bill play a significant role here. There is a penalty in terms of clarity, however, for using a lot of protein. Proteins often produce chill haze and cloudiness in lighter beers, so you need to balance the trade-off between head retention and clarity.
Hops also play a substantial role in head retention, which is why many IPAs have a nice layer of foam. The polyphenols in hops are actually critical to retaining foam bubbles, so go ahead and pile on the hops if it is appropriate to the style you are brewing. Brewing techniques also come into play. For example, choosing a higher mash temperature, such as something in the 154–158°F (68–70°C) range, will result in longer dextrin chains in the finished beer and lower attenuation during fermentation, which will enhance the head retention.
Finally, both the shape of your glass and how you clean your glasses will impact your head retention. A tall, thin Pilsner glass will trap more bubbles and foam over a smaller surface area, creating a longer-lasting head than the same beer poured into something like an English pint glass. Care for your glassware is also very important. Oils are extremely damaging to foam, so I try to avoid cleaning my glassware with household soaps that are oil-based. Even eating fatty foods while drinking your beer can transfer oil to the glass and ruin head retention.