Hot break is the clumping of proteins, solids, and tannins that fall out of the wort during the boil and eventually collect at the bottom of the kettle. A steady boil is the key to achieving a good hot break, which will typically occur 5-15 minutes after the boil begins. When the foam on top of your boil finally dissipates, you know that many of the proteins have coagulated and that your hot break has occurred. A hot break is important because it aids in removing undesirable and potentially off flavor causing tannins and compounds from the boil. It also helps improve clarity and reduces the risk of chill haze down the line.
Below is a photo of the hot break in a 20 gallon brew kettle, approximately 15 minutes after the boil first began.
Head retention refers to a beer’s ability to retain its foamy head once the beer has been poured. In most styles of beer, a thick foamy head that does not dissipate too quickly is very desirable. The three primary factors that impact a beer’s head are the carbonation level of the beer, residual proteins that form the body of the finished beer, and isomerized humulones pulled from the hops that were added during a beer’s boil. Hops that are added during fermentation or once the beer has cooled below approximately 175° F will not isomerize and will have very little impact on head retention. A stronger or hoppier beer will tend to have better head retention because it will usually have more residual proteins and a greater amount of isomerized humulones.
The most common ways of enhancing a beer’s head retention are to add high alpha acid hops during the boil, utilize grains such as crystal malts or wheat, or add an adjunct such as maltodextrin to your boil. Striking the right balance is a bit of an art, as you do not want to compromise the taste of your beer or risk clarity issues by pushing too hard for good head retention.
Body in brewing terms is often described as the thickness or viscosity of a beer as judged by your mouth. The body of a beer is typically described as thin, medium or full. Different varieties of beer are assumed to have a specific body profile; for instance a light lager or pilsner would be expected to have a thin body profile, whereas a stout would have a full body. The term mouthfeel is oftentimes used synonymously with body.
Determining factors in defining and making up a beer’s body include proteins, carbonation level, unfermentable sugars such as maltodextrin, water profile, and alcohol level.