Craft beer equipment needs to undergo boiling during the brewing process, during which some fantastic changes occur. However, for newcomers to craft beer, they may not be aware of these changes.
Changes in the wort during boiling
The hops dissolve and transform.
Protein-polyphenol complexes form and separate.
Water evaporates.
Wort sterilization occurs.
Enzymes are destroyed.
The color of the wort increases.
The acidity of the wort increases.
Reducing substances are formed.
Volatile substances content in the wort changes.
1. Dissolution and transformation of hops
Hop resin or hop bitterness is dissolved.
Hop oil is released.
Hop polyphenols are present.
2. Formation and separation of protein-polyphenol complexes
Both the polyphenols in hops and malt fully dissolve in the wort and bind with the proteins present. However, some polyphenols exist in an oxidized state, and the molecular size of the proteins varies, resulting in different complex properties.
The complexes formed by proteins and polyphenols, as well as proteins and oxidized polyphenols, do not dissolve under heat and precipitate as coagulates during boiling. Therefore, it is important to separate them from the wort as much as possible.
3. Water evaporation
The more vigorous the boiling, the greater the movement of the wort, leading to increased water evaporation. The amount of water evaporation is directly related to protein precipitation.
Excessive evaporation not only depletes water and energy but also incurs additional costs. Therefore, it is advisable to avoid boiling for an extended period.
4. Wort sterilization
During the brewing process, it is inevitable that bacteria will enter the wort. Boiling effectively kills these microorganisms.
5. Increase in wort color
The oxidation of melanoids and polyphenols formed during boiling contributes to the deepening of wort color.
6. Increase in wort acidity
Acidic melanoids produced and acidic substances introduced by hops contribute to an increase in wort acidity.
As acidity rises, the pH level in the wort decreases. This facilitates faster progress in essential processes and promotes the production of craft beer.
7. Volatile content in wort
Dimethyl sulfide, a volatile compound, affects the flavor of craft beer. An appropriate amount enhances the flavor, while excessive content results in undesirable taste.
Therefore, it is crucial to strictly follow regulations regarding boiling temperature and duration.
