With warmer weather come longer days, and cravings for lighter drinks, especially for outdoor activities like barbecues, beach days, and sporting events. Those looking for something to sip on during a day-long occasion may reach for something lighter in both flavor and calories. For homebrewers, this means planning ahead to have those summer brews ready to drink.

Making light- and low-calorie beer starts with designing a recipe and selecting ingredients that will impart flavor without increasing the calorie content. To make a low-calorie beer, homebrewers and professional brewers alike must balance the need for body and flavor with the goal to hit the all-important 100-calorie mark. This balance will make for an enjoyable drinking experience, and compete in calories with a new summer favorite: hard seltzer.

Three professional brewers from Stone Brewing, Anchor Brewing, and Anderson Valley Brewing Company discuss using different ingredients that contribute big flavor, without upping the calorie count: specialty grains and malts, real fruit, and carefully selected hops.

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Where Do Calories Come From in Beer?

Most of the calories in beer come from alcohol. The rest are made up from residual carbohydrates from malts and grains. In order to keep beer around 100 calories, it has to be low in alcohol (generally lower than 4.5 percent alcohol by volume) and low in carbohydrates left over after fermentation. Most commercial beers considered low carb will have fewer than 5 grams of carbs per serving.

Residual carbohydrates create sugars and proteins that increase calorie count. Texture and body are also influenced by sugars and proteins from residual carbohydrates, so it’s easy for low-calorie beer (and low-alcohol beer) to end up tasting watery — which is where a skilled brewer comes in. By creating a recipe that includes unique flavors from specialty malt, fruit, or other ingredients, brewers can combat a thin mouthfeel without adding calories or carbs.

Calculating the Calories in Homebrew

To calculate the calories in one serving of homebrew, all a homebrewer needs is two measurements: original gravity (OG) and final gravity (FG). These are both specific gravity measurements, usually taken with a hydrometer. OG is the specific gravity of the wort measured right before yeast is pitched; and FG is the final or finishing specific gravity measurement taken when fermentation has ceased completely. The OG and FG measurements are entered into the equation* below.

  • Alcohol Calories = (1881.22 * FG * (OG-FG))/(1.775-OG)
  • Carbohydrate Calories = 3550.0 * FG * ((0.1808 * OG) + (0.8192 * FG) – 1.0004)
  • Total calories in the final beer = Alcohol Calories + Carbohydrate Calories

*Equation as used in Beer Smith recipe builder.

A beer with an OG of 1.031 and an FG of 1.005 will have 3.41 percent ABV and exactly 100 calories per 12-ounce serving.

Commercial brewers have dialed in control of their yeast strains and can reliably finish as low as 1.000, which means they can achieve a slightly higher ABV, even at 100 calories. Examples include Lagunitas DayTime IPA at 98 calories and 4 percent ABV; Anderson Valley Black Rice Ale at 90 calories and 3.8 percent ABV; and Anchor Brewing Little Weekend at 100 calories and 3.7 percent ABV. For homebrewers, finishing at 1.005 is a bit more realistic, though finishing lower is definitely possible especially with the right yeast.

By deciding the starting (OG) and finishing (FG) gravity of a beer, the brewer is determining overall drinkability. This is true for homebrewers and pro brewers. Fal Allen, brewmaster at Anderson Valley Brewing Company, says, “I really feel that having a finishing gravity that is low makes a beer more sessionable and more accessible.”

A low finishing gravity (anything below 1.010) results in a beer that is drier and lighter on the palate. A beer with a higher finishing gravity (1.018 or above) will feel more full on the palate and seem more sweet, because of the thick mouthfeel resulting from more residual sugars or proteins.

To skip the math (and the need to remember the order of operations!), online calculators like this ABV Calculator from Brewer’s Friend can do the work for you.

How to Build a Low-Calorie Homebrew Recipe

Once the target measurements for OG and FG are set, the next step is putting together a grain bill to arrive at these targets. The trick is to include just enough specialty malt for flavor, without going too heavy on the carbohydrates. An example of this is Little Weekend, Anchor Brewing’s 100-calorie golden ale with mango. To hit the golden 100-calorie mark, Dane Volek, pilot brewer at Anchor Brewing, keeps the recipe simple with a malt bill of 80 percent pale malt and 20 percent Vienna malt, which is a specialty malt that is higher in carbohydrates/calories.

Volek landed on adding “just a kiss” of Vienna malt to help Little Weekend drink like a typical beer and keep it from being too thin or watery. “It gives it a bit more color, a little bit higher residual sugar, and a little bit more character,” he says.

Allen takes a different approach with Anderson Valley’s Black Rice Ale. He relies on the specialty grain to create the bulk of the flavor: “The black rice adds this unusual delicious umami flavor, so I was able to get a light beer that still packs a lot of flavor into it,” he says.

The rest of the fermentables in Black Rice Ale (ranked among VinePair’s 50 Best Beers of the Year for 2020) come from pale malt and a touch of chocolate malt for color.

“The rice only contributes enough color to make it a brown ale, and we were really going for black,” says Allen.

Fruit for Flavor, Not Texture

Mango is a popular choice for fruited beers because it adds flavor without the punchy acidity of citrus fruit. “Mango is one of those flavors that people really enjoy,” Volek says. “It has a juiciness and also a flashiness to it.”

To increase Little Weekend’s tropical fruit flavor without bulking up the carbohydrates and calories, Volek uses fruit purée. The mango purée is added right at the end of fermentation when the beer has almost reached the desired final gravity. “We only get a tiny bit of additional fermentation from the fruit,” Volek says, so there isn’t much alcohol created from fruit sugars.

Allen also adds fruit purées to specialty goses, which weigh in at 120 calories per 12-ounce serving when fermentation is almost completely finished. He says using fruit purées is the best way to get the flavor of real fruit (avoiding the artificial taste of extracts) without concerns for sanitation that can come with whole fruits (like the potential for bacteria on fruit skins).

By waiting for fermentation to be active, and nearly complete, the fruit flavor is there, but the sugars are metabolized by yeast and so do not contribute to the final calorie count in the beer. To match the technique of the pros, homebrewers should wait for gravity to get to a measurement within 0.005 and 0.003 of the target FG (or until bubbles in the air lock have almost ceased). Then, carefully add fruit purée directly to the fermenter.

Adding the right amount of purée takes some experimentation. Volek says that to keep the body of the beer light, you need to add enough fruit, but not too much so that the beer acquires texture from the purée. (We aren’t looking to make a smoothie beer!)

Hops for Bitterness and Balance (Not Flavor)

Brewers often turn to fruit or specialty ingredients to give low-calorie beer flavor that complements a very light body and low alcohol content. This is so common because hops can quickly become uncomfortably bitter with no body or sweetness for balance. That’s why Stone Brewing Company’s Features and Benefits IPA was such a big challenge for senior manager of brewing and innovation Jeremy Moynier.

“A lot of low-cal beers are lagers, but Stone is really well known for making IPAs and we wanted to live up to those expectations,” Moynier says. The trick to extracting maximum citrus and fruit flavors from hops like Azacca and Mosaic, without adding too much bitterness, was “loading the back end of the beer with more hops and continually playing with amounts and varieties,” he says.

For Features and Benefits, Moynier landed on a blend of Cashmere, Vic Secret, Azacca, and Mosaic hops to bring pungent flavors of orange, pear, white peach, and melon, while only adding 29 IBUs (a measure of bitterness).

Adding hops during or after fermentation ensures temperatures will never be high enough to convert hop acids into bitter iso-alpha-acids (a reaction that occurs at temperatures around 180 degrees Fahrenheit). Without the iso-alpha-acid conversion, hops contribute mostly highly aromatic essential oils at this stage of the brewing process, meaning more fruity notes in the final beer.

At Anchor, Volek is also conscious of how much bitterness is extracted from hops when brewing lighter-bodied beers. For Little Weekend, Volek says, noticeable bitterness is important to balance the sweetness from mango and Vienna malt. At Anderson Valley, for light-bodied beers like Black Rice Ale, Allen says he only adds enough hops to benefit from their antimicrobial properties. He sticks to “very neutral hops, and we don’t dry-hop or use finishing hops, so they are just there to balance malt sweetness.”

Final Recipe Considerations for Brewing Low-Calorie Beer

Since calculating calories is dependent on OG and FG (per the equation above), it is essential to hit these two target measurements.

To ensure the proper OG is achieved, Volek recommends using two mash temperatures, which will get the most out of enzyme activity. He suggests a mash step at 140-142 degrees Fahrenheit, and a step at 148-150 degrees Fahrenheit. These lower-temperature steps ensure that beta amylase is continually used to convert the maximum amount of starch into sugars that can be completely fermented out by yeast (therefore, producing lower gravity measurements).

When it comes to selecting yeast, Moynier says almost any brewers yeast will work because the desired alcohol content is so low. It is important, however, to select a yeast that the brewer has experience with and is comfortable using. “We have a house yeast that we have been using for years, and know fully what it can and can’t do,” Moynier says.

To brew a sessionable summer sipper that hits the same calorie content as a hard seltzer, it’s all about calculating the target gravity, adding flavor while maintaining balance, and hitting your measurements on brew day and through fermentation. Hitting every point on the checklist will all be worth it when you can kick back outside with homebrew that is light enough to enjoy all day!