Chapter 12

Wort Cooling and Aeration

Formation of Cold Break

As the clear hot wort is cooled, the previously invisible coagulum loses its solubility and precipitates. The precipitate is referred to as the cold break and begins forming at about 60C (7). The cold break mostly consists of protein-polyphenol (tannin) complexes, whereas the hot break is mostly proteinaceous. The cold break also has a higher level of carbohydrates (primarily beta-glucans) than hot break (10).

Factors Affecting Quantity of Cold Break

The total dry weight of cold break is between 15 and 30 g/hl, accounting for about 15 to 30% of the total trub material precipitated during cooling and boiling of the wort. The actual amount produced in a given wort depends on numerous factors, such as malt modification, mashing program, wort temperature, the presence of hops, and the rate of hot break removal.

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