The term Body of a beer refers to the weight and mouthfeel of a brew. Higher body is achieved by raising the final gravity of a beer without producing an incomplete fermentation. Body is a desirable characteristic for many popular beers styles. Body can be enhanced by adding unfermentable (complex) sugars, and also by increasing the amount of protein in the brew.
Methods for Increasing Body
- Adding carmelized sugars (caramel, roasted, malto-dextrin and dextrine malts)
- Adding proteins from ingredients such as oatmeal, unmalted grains, flaked barley
- Increasing mash temperature during sugar conversion
Carmelized and Roasted Malts
Malts that have been carmelized like caramel or crystal malts have long chains of sugars that are called dextrins. Even lighter caramel malts such as Carapils have dextrins in them. Malto-dextrin powder also enhances the amount of dextrin. Dextrin sugars are carbohydrates that are almost tasteless, do not ferment well, and subsequently remain in the finished beer enhancing the mouthfeel and perceived body to the brew. Roasted, chocolate, and special malts have a high proportion of other unfermentable sugars, and similarly increase the finished body while adding sweetness, raising FG, and enhancing flavor.
Body Enhancing Proteins
Unmalted grains and many non-barley grains contain a large percentage of proteins. Examples include Wheat, Oatmeal, Flaked Barley, unmalted barley and undermodified malts. Proteins do not ferment well and can have a profound effect on enhancing mouthfeel. Unfortunately proteins also reduce clarity of the finished beer, so large amounts of protein enhancing ingredients are best used in darker beers (Oatmeal Stout) or beers that are characteristically cloudy (many wheat beers).
A final method for enhacing beer body is to increase the temperature when mashing. A higher temperature during the saccrification step (convert at around 158F) will reduce the effect of the beta amylase enzyme leaving larger sugar chains in the beer. This will enhance the amount of unfermentable sugars and increase the body of the beer again resulting in a higher final gravity.