The moment of truth has arrived. You hand your best buddy and toughest critic a pint of your latest brew. He raises the glass to his lips and sips. And says with a shrug, “Not bad. A little roasty for a mild ale.” Hmm. Problem is, this recipe was for an imperial stout.
Your friend’s beer-tasting qualifications aside, what he may have been getting at but didn’t quite articulate was that your beer lacked body. If that comes as a surprise, read on. If you don’t understand the concept of body and what factors influence it, you can’t appreciate what you’re doing to kill it.
Body, also referred to as mouthfeel, is the sensation of palate fullness or viscosity (sometimes called thickness) on the tongue. Literally, the way the beer feels in your mouth. Body is detected soon after the first sip.
Take a mouthful of beer. Is it thin? Almost chewy? Somewhere in between? Think of drinking a glass of water as opposed to a glass of orange juice.
The trigeminal nerve is responsible for this sensation. Unlike the olfactory (smell) or gustatory (taste) nerves, the trigeminal nerve
produces a physical or tactile sensation. The trigeminal sensation is also responsible for detecting carbonation and for the perception of afterfeel.
The feeling of fullness or body is created by the concentration of solids in the finished beer. The presence of solids in your beer doesn’t mean you’ve created a new “chunky” style. The term “solids” refers to the larger protein molecules that remain in suspension in the liquid throughout the brewing and maturation processes. This includes remaining yeast that has not flocculated (settled) out. These solids are products of the breakdown of starch and the solubilization (dissolving) of proteins during the mashing process that survive fermentation intact and so are present in the final beer. Large protein molecules make up the bulk of a beer’s body, but unfermented sugars (dextrins) play a role, as well.
Choosing a Victim
The style of beer you’ve chosen to brew dictates the body of your beer, which will range from light- to medium- to full-bodied. A
Berliner weizen should be light-bodied and refreshing, while you’d expect an English brown ale to be medium-bodied. An imperial stout
is supposed to taste, well, majestic.
As one would expect, thin-bodied beers have a lower specific gravity than fuller-bodied brews.
If your stouts consistently have the body of brown ales, your bocks that of American lagers, and your Scottish ales the body of bitters, then your brewing technique needs a workout. But before you work on building that body, first look to see if you’re doing something to kill it.
Several factors have a direct impact on body, among them the grain bill, mash temperature, filtration, and contamination. The two main reasons, and the most common, for not achieving sufficient body are an inadequate grain bill and an inappropriate temperature in the mash.
The Usual Suspects
First, let’s look at the most obvious: your ingredients. Whether you’re an all-grain brewer or an extract brewer using a partial mash, you can’t expect to make a bock with the same amount of malt you use for a lighter lager. Heavier beers require heavier grain bills.
Malt extracts that are low in proteins yield a thin-bodied beer. Obviously, the amount of grain or malt extract used also has an impact on body. Increasing the amount of grain or malt extract used increases the body. Adding dextrin malt, also known as carapils, enhances body and also head retention, as many thin-bodied beers have poor foam stability. Dextrin malt is used frequently in light lagers and also balances the flavor of darker beers and ales.
Overmodified specialty malts — anything other than pale malts and especially crystal, caramel, and carapils — need to be included in the grain bill of any full-bodied beer.
Adjuncts also play a role in establishing the body of a beer. For example oatmeal, rye, and flaked barley, all high in beta-glucans, contribute to mouthfeel and head retention but can also make for a sticky mash. Corn, rice, and wheat, on the other hand, are used to thin out body.
For extract brewers, bulking up on malt and including one to two pounds of grain in a partial mash, if you’re not already doing it, are your best bets.
On the other hand all-grain brewers who are using a proper grain bill and still not getting satisfactory body need to look more closely at their mashing regimen.
The purpose of mashing is to convert the starches present in malted barley to fermentable sugars and other materials. Simply put, the degradation of starch is facilitated by a variety of enzymes that work within specific temperature ranges.
Beta-glucans, long chains of fermentable glucose molecules, are one of the initial byproducts of the mashing process. Beta-glucans are partially soluble (dissolvable) in water. Their solubility increases in hot water and when they are broken down into smaller units. Beta-glucans can be described as gummy and are major contributors to mouthfeel and viscosity. Unfortunately, due to their sticky nature, they can make lautering and filtration difficult.
In the mash beta-glucans are broken down by enzymes called beta-glucanases. Because of their low temperature stability, they are only active during the first few minutes of the mash. Optimal temperature for beta-glucanase is about 122° F.
The use of a low-temperature protein rest increases the activity of beta-glucanases, allowing them to work efficiently, which reduces the amount of remaining dextrin.
This means that using a higher temperature infusion mash (152° to 158° F) and eliminating the lower temperature protein rest results in a brew that is richer in dextrins and more full-bodied. Conversely, employing a step mash with lower temperatures results in a lighter-bodied beer.
Of course, finding just the right temperature or temperatures to complement each beer style you brew is a matter of trial and error.
Standing in the Lineup
Other factors that are detrimental to body are filtration and contamination. If you’re filtering your homebrew and have a problem producing anything but light-bodied beers, consider foregoing this step. Filtering can remove many of the solids that contribute to body, as well as
stripping away flavors.
Contamination caused by wild yeast and bacteria can weaken body by breaking down carbohydrates, resulting in a thin-bodied beer. Of course, this should be easy to pick up because your beer will also have off-flavors.
The solution? Sanitize everything that comes in contact with your beer religiously and thoroughly, including your bottle caps.
All-grain brewers should note that the wort chiller is often a likely source of contamination.
Age also plays a role. A beer needs to age properly to exhibit its true body. And like the human body, beer body also can suffer from the ravages of time.
Adjuncts introduced after the fact, such as lactose, also can be used as body enhancers. When lactose, or milk sugar, is added to fermenting or unfinished beer, it imparts a slight sweetness and smooth mouthfeel. Some brewers prefer to add it at the end of the boil for sanitization
reasons. Available in crystal form, lactose is a common ingredient in milk or sweet stouts.
Gretchen Schmidhausler is a graduate of the American Brewers Guild’s Craftbrewers’ Apprentice program. She has been a homebrewer for a number of years.