While the origins of beer have been cause for much debate, it is widely accepted that, for much of human history, beer has been considered beneficial for the promotion of health and nutrition. Made from a variety of cereal grasses, the connection between beer and bread was virtually inseparable, with many of the early-recorded recipes including the addition of bread and bread-like substances. Beer was so connected with health and nutrition, one can find it in the medical history of the West. The Egyptians used beer to fortify the infirmed. Hippocrates, the father of western medicine, used beer to treat fevers and wounds. Physicians in the UK once prescribed Guinness to pregnant women as an early form of pre-natal vitamin, as the beer was often rich in iron and B vitamins. There is even evidence in the current scientific literature that moderate beer consumption can promote improvements in overall health. In fact, the idea that beer is healthy and nutritious is so deeply imbedded in British culture that the Royal College of Physicians (RCP) was compelled to release an official statement tampering the health effects of drinking in 2014. In that statement, the RCP noted, “There is no evidence to suggest that the health of non-drinkers will improve if they start drinking alcohol. Also, any potential benefit that can be obtained from drinking moderate amounts of alcohol, for example two glasses of wine a week, well below most drinkers’ consumption, will be wiped out by intermittent binges.”
While people have been touting the health benefits of beer for millennia, the 20th century brought a recognition that every bottle of beer brought untold calories. The Coors Brewing Company gave the United States its first light beer in the form of Coors Light just before World War II. While this first offering of Coors Light was short-lived, it introduced the American drinking population to the idea of a lighter, more refreshing beer that won’t jeopardize the fighting readiness of the American soldier. Now, as American dieting trends are again moving us away from mass carbohydrate consumption, big beers that have been the darlings of craft beer enthusiasts are now making room for session beers and even alcoholic seltzers. The acknowledgement that we are drinking a lot of calories has American drinkers taking a closer look at their beverages.
So, where do the calories come from? The first source is the alcohol. Alcohol contains seven calories per gram. This means that in a 12-ounce (355-mL) beer at 5% ABV, 98 calories are contributed by the alcohol:
355 mL x 0.05 ABV = 17.75 mL
17.75 mL x 0.79 g/mL = 14 grams alcohol
14 g x 7 kcal/g = 98 calories
The rest of the calories come largely from the residual dextrins left over from the mashing process. Dextrins are branched chains of glucose molecules. While they are too big to be fermented by yeast, they provide body and residual sweetness to beers. As the popularity of craft beer has increased, the calorie count in beers has also risen dramatically as alcohol, malt, and hops has increased. While hops do not directly contribute to the calorie count of beer, their bitterness needs to be balanced by residual sweetness. This is often accomplished with higher mash temperatures, which favor alpha amylase conversion, pushing the formation of dextrins. This is why the average calorie count for an IPA is around 200 calories, while a double IPA can reach as much as 300 calories per 12-ounce (355-mL) serving. This is more than two 12-ounce (355-mL) bottles of Coca-Cola.
Aside from alcohol and carbs, there are other ingredients that can drive up the calorie count in a beer. Fruit purees and juices can be a source of additional calories. Milk stouts and milkshake IPAs are made with the addition of lactose, a sugar that cannot be utilized by yeast, but can be metabolized by humans. Candi sugars, which are popular in Belgian-style beers, are sometimes partially caramelized, rendering much of the sugar in these caramelized products to be inaccessible for yeast but able to be processed by humans. Lastly, yeast can only tolerate a certain amount of alcohol, depending on strain, and if they cease fermentation before all of the fermentable sugar is utilized, then the residual sugars will also contribute to a higher calorie count.
To achieve a low-calorie beer, the key is to develop a recipe with a low original gravity containing highly fermentable sugars. Here are a few simple techniques that can help achieve those goals.
Techniques to Cut Calories
First, manage your mash carefully. For those of us who are new to all-grain brewing, sugar is stored inside grain in the form of starch, which is composed of long chains of glucose molecules. These chains can be long and straight, which is called amylose, or composed of lots of branches, which is called amylopectin. During the mashing process, hot water is added to the grain at a specific temperature range to encourage enzymes within the malt to chop up those long chains of starch into smaller fermentable sugars. Maltose, which is composed of two glucose molecules, is the primary fermentable sugar produced during the mash. Maltose is the primary product of beta amylase, one of the enzymes in malt that convert starch into fermentable sugars. Beta amylase is precise, making only maltose molecules, and functions between 140–149 °F (60–65 °C). Alpha amylase is rogue, slicing any linear bond between glucose molecules. Alpha, which functions best between 149–162 °F (65–72 °C) can form glucose, maltose, and maltotriose from starch molecules, which are all fermentable. Alpha amylase is also associated with the formation of dextrins. Neither alpha nor beta amylase can break the bonds that cause branches in amylopectin. As a result, fragments of these branches are often left in the wort. These fragments increase body, sweetness, and calories.
My technique to reduce the dextrin potential of a wort is to do a long mash that starts at the overlapping temperature of alpha and beta amylase, 149 °F (65 °C), and then drop into beta to help maximize the fermentable extract that can be pulled out of your mash. Theoretically, by starting with alpha, I am making more non-reducing ends for beta amylase to interact with. By dropping the temperature down to beta temperatures after a co-alpha rest, the amount of fermentable sugars is maximized. In addition, there are exogenous enzymes like glucoamylase and Fungal α-amylase that can be added that will work under a broad temperature range to break down dextrins into fermentable sugars.
There is also an enzyme called amyloglucosidase (AMG) that can be added to the fermenter that will work at room temperature to minimize the dextrin content of your beer. For this activity, it is important to look for an enzyme that works on both 1-4 glucosidic bonds (the linear bonds) and 1-6 glucosidic bonds (the bonds responsible for the branches in dextrines). The breaking of these bonds result in a highly fermentable wort. Sebstar makes a product called SebAmyl GL that will break all of these bonds. Care should be taken to ensure you have hit terminal gravity before packaging after adding this product as these enzymes will still function at room temperature and any residual dextrins may still break down and provide excess sugar for the yeast, resulting in potential gushing and bottle bombs from over carbonation.
Another way to hit your target original gravity while minimizing the dextrin potential is to use sugars and syrups that are completely fermentable. Big breweries often use rice and corn syrups, which are mostly composed of glucose and fructose, to achieve gravity while ensuring that the yeast can utilize all of the sugar, reducing the calorie potential of the beer. This is a viable option for homebrewers, but care should be taken that the syrups used have a low dextrin potential. Syrups used in food products like granola or sweetened beverages have a higher dextrin potential to promote a luscious mouthfeel. Syrups used by brewers have an extremely low dextrin potential. If in doubt, ask your supplier. Reputable suppliers will be able to answer your questions.
Sugar additions are another way to reach your target gravity without risking residual sugars increasing final calorie count. Sucrose is the primary molecule in table sugar. Composed of a glucose and a fructose molecule, sucrose is completely fermentable and should not leave any sugars behind to increase the calorie count of your beer. By replacing a percentage of your malt bill with a sugar or syrup addition, you can reduce the potential for residual dextrins. It should be noted that if you choose to include sugar additions in your recipe, add them towards the end of your boil. This will minimize the formation of Maillard products that may decrease the fermentability of the sugar addition.
For brewers using malt extracts, there is a little extra care necessary to reduce the calorie count of your beer. Malt extracts are standardized for consistency, and often target a medium-bodied mouthfeel with moderate to low residual sweetness. As a result, there are residual dextrines in malt syrups that cannot be fermented, and will increase the calorie count of the beer. Exogenous enzymes can be used to break down these residual enzymes. In addition, rice syrups and exogenous sugars can be used to reduce the amount of malt syrups being used to produce the beer.
So, now that we have addressed ways to minimize calories, let’s discuss ways to maximize flavor. Traditionally, much of the flavor from beer comes from the malt, but if you have chosen to minimize your malt bill in favor of more fermentable sugars, then you have to look towards microorganisms. Yeast is the main microbe brewers lean on to bring flavor to a beer. Aside from their role in creating alcohol, yeast can provide a lot of additional flavor compounds to beer. Whether it’s the bubblegum and banana found in a traditional hefeweizen strain, or the spicy phenolics created by a saison yeast, a brewer can manipulate pitch rate, temperature, and wort composition to push for specific flavors in beer.
One of the easiest ways to manipulate yeast flavor is to push ester formation. Esters are the fruity and floral flavors in beer that are not typically associated with hops. This can be done in a variety of ways, but the easiest is a secondary addition of yeast nutrient. Yeast convert amino acids, the building blocks of proteins, into esters after the initial growth phase. By adding a yeast nutrient two to three days into a fermentation, you are taking advantage of the yeast’s esterification pathways to produce the desired fruity and floral flavors. Combined with yeasts known to produce lots of esters, like British ale and lager yeasts, the ester content can be increased significantly.
Lastly, you can control the residual sugar by the type of yeast you choose to use. Using a high-attenuating yeast, or a yeast that can ferment a lot of sugar and tolerate higher alcohol contents, helps minimize the residual sugars left in your final product. In addition, some yeasts contain a gene, commonly referred to as the diastaticus gene, that results in the production of extracellular amylases, which helps them break down dextrins into smaller fermentable sugars. Many saison and Brettanomyces sp. yeast strains have this gene and, given a long enough fermentation period, can reduce the dextrin content of a beer. Care should be taken when using diastaticus strains to ensure that the beer has hit terminal gravity to prevent explosions when packaging.
Hops can be a great source of flavor in a light beer. Since light beers do not typically have a strong malt backbone, they do not require a lot of hop bitterness to provide balance. However, the biotransformation of hop oils can provide a lot of flavor to your final product. When choosing a hop bill, look for hops with a low percentage of alpha acids and a profile that is fruity and floral. One of my favorite hop varieties is Bramling Cross. This is an old British variety that offers a strong finish of black currants. By adding these types of hops as finishing additions or dry hopping, you can push the development of aromatic compounds that bring a lot of flavor to a beer. You can also purchase isolated hop oils and add them directly to your beer. When using these products, a light touch is necessary to avoid overpowering your beer.
Spices are another way to drive flavor in a lighter beer, but they are often best used sparingly. Warming spices like cinnamon and nutmeg can give the perception of sweetness without increasing the carbohydrate content. For the most part, spice additions are best done in the kettle as raw spices can be harsh and astringent in your final product. That being said, delicate spices like saffron or elderflower do well as additions after primary fermentation so their volatile compounds can be preserved. When in doubt about when to add a particular spice to your process, think about how it is used in cooking. If a spice is typically added during the cooking of food, then add it to your boil. If it is a spice that can be sprinkled on before eating, then it is usually fine to add during fermentation.
Lastly, fruit additions can bring a lot of flavor to a beer, but if the intention is to reduce calories, they must be conducted carefully. Fruit juices and purees offer a lot of flavor, but they also contribute calories. Since fruit juices and purees contain largely fructose, glucose, and sucrose, the sugars in them are highly fermentable and should not leave residual sugars if accounted for in the original gravity calculations. Fruit skins are another great source of flavor. Full of polyphenols and aromatic compounds, fruit skins are responsible for most of the flavor associated with the fruits they come from. Not convinced? Take a bit of a plum without the skin. It will be very sweet, but generic. Now try it with the skin. A lot of the tart herbaceous taste of plums comes from the skin. Fruit skins can be treated just like delicate spices, adding them to the secondary to preserve the volatile compounds.
Fruit can also be added as extracts and essences. If using these, it’s important to use all-natural products to avoid chemical or artificial flavors. My favorite line of extracts to use is from Amoretti. They are all-natural and high quality. These are usually highly concentrated so start small and add them as you would fruit skins or delicate spices.
Approaching Your Recipe
The beautiful thing about lower-calorie beers is that you are working with a more neutral palate. This makes it easy to add delicate flavors and blend them without competing with bold malt flavors or aggressive hops. When developing your recipe, it is important to remember that low-calorie beers are typically warm weather beers, so the recipe designs that focus on flavors that can be enjoyed in warmer weather can be really successful.
For example, a little bit of vanilla extract combined with some orange peels can become a creamsicle ale. Some lemon peels and fresh mint in our fermenter can give you beer that tastes of lemonade. Do you prefer Arnold Palmers? Sour your beer through the mash or in the kettle and add a small amount of black tea to your fermenter. For a truly refreshing offering, try adding fresh cucumbers and basil directly to your fermenter.
If you are a fan of darker beers, this style is still open to you. There are ways to get that dark beer flavor without using dark malts. Adding cacao husks, the husks that are broken off of cacao beans before roasting, to your mash can impart a lot of chocolate aroma without overpowering the flavor of your beer. Combined with a few ground coffee beans in your fermenter, and you have a light mocha lager. A little rose water, honey malt, roasted barley, and pistachios with an English ale yeast can give you beer that tastes remarkably like baklava. In addition, the Scottish company PureMalt has a line of malt concentrates under the Crafted label that can add the flavor of a dark malt, like a crystal or chocolate malt, without additional calories. Distribution is limited in North America now, but it is an option to keep an eye on in the future. More on this product can be found at http://www.puremalt.com/crafted.
At the end of the day, there are many reasons why people choose low-calorie beers. Despite all of the derision that light American lagers and low-calorie beers receive, they are still the biggest selling beers in America. The desire for a low-calorie option does not have to mean low in flavor. This is a style that opens up opportunities to be truly innovative in flavor development. It’s one of the few styles that can directly reflect much of the flavor diversity the world has to offer, so whether you make a bloody mary lager, or a green papaya ale, you can approach this style in the same way you approach your food. At the end, you will walk away satisfied.
Now that we have laid out techniques to reduce calories and maximize flavor, it’s time to provide an example recipe to utilize this information.
Rye Brut IPA
(5 gallon/19 L, all-grain)
OG = 1.039 FG =1.005
IBU = 20 SRM = 4 ABV = 4.5%
7.4 lbs. (3.4 kg) pale malt
1.25 lbs. (0.57 kg) rye malt
6.75 AAU Columbus hops (15 min.) (0.5 oz./14 g at 13.5% alpha acids)
1 oz. (28 g) Kohatu hops (0 min.)
4 oz. (113 g) Nelson Sauvin hops (dry hop)
1 oz. (28 g) grains of paradise (15 min.)
1⁄2 tsp. Glucoamylase (AMG) in fermenter
Omega West Coast Ale I (OYL-004) or SafAle US-05 yeast
3⁄4 cup corn sugar (if priming)
Step by step
Focusing on mash schedule and exogenous enzymes, I endeavored to make a flavorful all-grain beer with an ABV above 4% but that comes in at about 120 calories per 12-ounce (355-mL) serving. As we discussed previously, mash schedule is important in reducing the unfermentable dextrins that add unwanted calories. In my converted cooler mash tun I know I consistently lose 8 °F (4 °C) when I mash in, so to target the 149 °F (65 °C) we mentioned before I mash in at 157 °F (69 °C). It is incredibly useful to have this kind of understanding of your equipment. You can come to learn the ins and outs of your setup over time or you can spend the time to do several trials to fine tune it. After mashing in I let that temperature coast downward. In fact, because I wanted to move the temperature into beta amylase range for this beer, I left the lid off of the mash tun for the first 30 minutes and stirred it three or four times. In those 30 minutes the temperature dropped to 145 °F (63 °C) and I put the lid on, losing just 1 °F (2 °C) over the final 30 minutes of the mash. These steps helped make sure I maximized the fermentable potential in my conversion and minimized dextrin production.
The boil for this beer is very straightforward. Sixty-minute boil, adding spices and hops with 15 minutes remaining in the boil and hops again at flame out. The grains of paradise are a spice I love in lighter beers. It is related to cardamom and comes from West Africa. Grains of paradise bring a sweet and spicy flavor but also have a botanical component. I always get a subtle lavender and juniper when I use this spice.
After cooling to my yeast-pitching temperature and inoculating with yeast, I added glucoamylase. Earlier we mentioned “exogenous enzymes,” these being ones that you are adding to your process as opposed to “endogenous,” which would be the naturally occurring enzymes in your base malts. Glucoamylase will continue to break down any of the remaining dextrin chains into fermentable glucose molecules.
With the mash schedule, and the use of the glucoamylase in the fermenter, I have been able to push the final gravity as low as 1.002 but over my trails with this process I average 1.005. The beer is light with a spicy bite on the tongue and subtle botanical aromas in the nose. With a starting gravity of 1.039 and a final gravity of 1.005 this recipe comes in at around 4.5% ABV and 125 calories, just missing my goal of 120 calories. If desired, I could push the final gravity down a little by swapping some of the grain out and replacing it with 100% fermentable sugar.
Partial mash option: Swap out 6 lbs. (2.7 kg) of the pale malt for 3 lbs. (1.4 kg) of extra light dried malt extract. Mash the crushed grains in a muslin bag in 1 gallon (3. 8L ) water. In a similar fashion as the all-grain version, mash for 60 minutes starting at 149 °F (65 °C) and allowing the temperature to drop to about 145 °F (63 °C) during the first 30 minutes, then maintain that temperature for the duration. Remove the bag and wash grains with 1 gallon (4 L) of hot water. Top up the kettle and add dried malt extract and bring to a boil. Follow the all-grain instructions for boil, fermentation, and packaging.