Chapter 10

Wort Boiling

Formation of Hot Break

During wort boiling, hot break forms largely from the interactions of denatured proteins and simpler nitrogenous constituents with carbohydrates and/or polyphenolic compounds (e.g., tannins, flavanols, and anthocyanogens) to form large particles referred to as trub or “hot break.” When boiling is completed, the wort should be brilliantly clear, with mostly large particles of trub and spent-hop material. If the break is too fine, this can be the result of using less-modified malt, of insufficient boiling action, or of brewing water that is high in carbonates.

Factors Affecting Quantity of Hot Break

The amount of trub will be on the order of 200 to 400 g/hL wet weight (approx. 80‒85% water). The quantity of trub depends on type and amount of malt, use of adjuncts, mashing program, duration and vigor of the boil, wort pH, and type of polyphenols.

Factors Affecting Quality of Hot Break

It is important, at this stage of the process, that most of the proteins and polyphenols have been precipitated. If not, this could complicate fermentation and filtration of beer, and persist into the finished product, causing haze. However, even under ideal conditions, precipitation of these materials is not complete.

Qualitative Assessment of Hot Break

At the end of the boil, a sedimentation test is carried out on 1 liter of wort in an insulated Imhoff cone to assess how well the protein has been coagulated. After 5 minutes, the wort should have a brilliant background clarity and the trub should have compacted to a level below 100 mL/L (Barnes, 2006).

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