With the popularity of low-carbohydrate diets in the early 2000s, low-carb versions of almost every product quickly popped up to fit consumers' needs, including, not surprisingly, Low-Carbohydrate Beer. Most commercial examples are low-carb versions of large breweries' generic American Pale Lager style beers.
Brewing Low-Carbohydrate Beer
While primarily a commercial product, there is a fair amount of interest among homebrewers in brewing low-carb beer, both because many homebrewers have started low-carb diets and have trouble fitting homebrew into them, and because of the blandness of most of the commercially available versions.
The primary variable affecting the amount of carbohydrate in finished homebrew is the conversion of starch to fermentable (rather than unfermentable) sugars in the mash. In addition to controlling mash time and temperature, some have suggested using additives, such as Beano, to break down additional carbohydrates. However, too successful a conversion, such as that achieved with Beano, can result in significant changes in flavor and mouthfeel. The brewer's best bet is to start with a session beer that already has relatively low carbohydrates, such as a Dry Stout.
The BJCP does not define a style for low-carb beers; they should be entered either in the base style category to which they belong, if the low carbohydrate content does not detract from the flavor and mouthfeel of the beer, or in the Specialty Beer category.
The GABF, with its emphasis on commercial beers, does define one style, although it only encompasses low-carb versions of standard American pale lager.
GABF Style Listings
American-Style Low-Carbohydrate Light Lager
|These beers are extremely light straw to light amber in color, light in body, and high in carbonation. They should have a maximum carbohydrate level of 3.0 gm per 12 oz. (356 ml). These beers are characterized by extremely high degree of attenuation (often final gravity is less than 1.000 (0 ºPlato), but with typical American-style light lager alcohol levels. Corn, rice, or other grain adjuncts are often used. Flavor is very light/mild and very dry. Hop flavor, aroma and bitterness are negligible to very low. Very low yeasty flavors and fruity esters are acceptable in aroma and flavor. Chill haze and diacetyl should not be perceived.||