Cold Break is an amalgam of proteins, protein-polyphenol complexes, and carbohydrates that precipitate from wort upon cooling and can contribute to chill haze if left in solution.
Various methods will extract or separate the cold break from the wort. Regardless of the method, rapid cooling of the wort is essential to the precipitation of cold break and its subsequent removal from the wort. Some breweries will transfer the wort to a settling tank either prior or subsequent to yeast pitching to allow the cold break to fall to the bottom of the tank, whereupon it is removed from the cone. Conversely, flotation of the cold break via the introduction of sterile air, whose bubbles bind to the cold break and float it to the surface, can also prove effective at removing cold break. After 2 to 3 hours a brown, compact head forms on top of the wort. The wort is then removed from the bottom of the tank, leaving the cold break behind. These methods are time consuming, however, and fraught with potential for bacterial contamination. Centrifugation of the wort prior to pitching is rapidly becoming one of the more popular methods of cold break removal, yielding removal rates of 50%–60%. Diatomaceous earth filtration offers even greater results.
Cold break can cause unwanted beer haze, but it is also a source of yeast nutrients, namely sterols and unsaturated fatty acids. Studies have shown that total elimination of cold break can result in slower fermentations, lessened yeast viability, higher acetate ester levels, and an increase in dissolved carbon dioxide levels during fermentation resulting in incomplete fermentation.