One of the best compliments that a homebrewer can get is having her/his beer compared favorably to a well-respected commercial example. Scoring that praise takes more than great flavor, though; the beer has to look good, too. Clarity is a big factor, but head retention is arguably even more important. A flat, lifeless beer is anything but impressive, while a thick, rocky layer of foam invites indulgence. But that pretty head is not merely ornamental—it opens up the aroma and enhances your ability to smell the beer. It also keeps the beer fresh on your palate as you drink.
Dress for Success
If your beer isn’t making the best first impression, the problem might have more to do with the glass than the beer itself. Poor rinsing can leave glassware coated with a thin film of soap. Look closely, and you might see a light haze, or it may be virtually invisible. But soap will sabotage any foam your beer tries to raise. Before you make recipe or process changes, your first step should be to thoroughly clean your glasses using a non-detergent cleanser such as OxiClean.
The right glassware can also make a difference. Good quality glasses are often etched at the bottom to provide nucleation points for bubbles to form. This boost in foam production can help build a head on your beer and keep it there.
Time for a Makeover?
If cleaning the glassware or changing out the glass doesn’t make enough of a difference, it’s time to look at your ingredients and your process. Building up a good layer of foam requires bubbles and some kind of structural backbone. Your brewing decisions will determine whether your beer has what it takes.
Carbonation
Without carbon dioxide bubbles, there’s no hope of having much head. If your beer is short on carbonation, you need to make sure that you’re adding in enough CO2 and keeping it under pressure. Kegs are simple; any problems achieving carbonation are usually due to leaks. Bottle-conditioned beers can have a couple of issues. If a batch of bottles varies in carbonation, next time you bottle, make sure your priming sugar is well distributed in the batch before bottling and pay attention that your seals are good while capping. Otherwise, if you’re following standard recommendations for priming, low bottle carbonation is often due to weak yeast or environmental issues such as low-temperature storage. If your beer spends a long time aging in the fermentor, you may need to add some fresh yeast before bottling. Also, remember that bottle conditioning is a mini-fermentation happening in the bottle. Give the batch time to carbonate at room temperature before refrigeration.
Stabilizers
A strong head gets its structural strength from medium-length proteins supplied by the grains. You can increase these proteins by using the same techniques you’d rely on for improving mouthfeel and body. Adding specialty malts such as flaked barley, flaked wheat, or dextrine (Carapils) to your recipe will increase the proportion of these proteins. Darker crystal malts will also help, but they have a stronger impact on the flavor. Be careful overdoing it, though, because the higher proportion of proteins can also lead to chill haze. If the style permits, kicking up the hops can help out, too. The isohumulones from hops give the bubbles a longer lifetime by supporting a higher surface tension.
All-grain brewers have some additional control via the mash process. If your recipe includes much in the way of under-modified malts, a protein rest at 131°F (55°C) can help break up long-chain proteins so they can contribute to stability. On the other hand, if your malt bill is mostly highly modified malts, then a protein rest will do more harm than good. A higher saccharification temperature (e.g., 158°F/70°C), which favors body and mouthfeel, can also improve head retention.
A final option is to take advantage of heading agents. These are generally added at bottling time. If you’re brewing extract-only beers, this may be your best choice, although steeped grains can usually provide the necessary proteins without softening the flavor.
Decapitation
You may be giving your beer all it needs for good head retention—the carbonation, medium-weight proteins from malt, and isohumulones from hops—but still have problems. Some of this may be due to other ingredients in the beer. Oatmeal, coffee, chocolate, citrus, or chiles can all add fats or oils that cut short the bubbles’ lifetime.
Higher alcohol levels also weaken head retention; it’s harder to get a thick head on a barleywine or imperial stout. Fortunately, your commercial competition will have the same challenges.
On the process side, it’s possible that a long, overly vigorous boil can break down the medium-chain proteins that a big head depends on. Surprisingly, yeast health and fermentation temperature can also be a factor. Stressed yeast is more likely to produce higher alcohols (fusel oils), which will also break down foam fairly quickly.
Finally, we’ll come back full circle to cleaning. Clean your carboys and other equipment with non-detergent cleansers to eliminate the chance of soap residue killing your head.
Heading Out
In most cases, cleaning your glassware and adding a pound or so of flaked wheat can be enough to improve your head retention and enhance the perception of your beer.