Fundamental changes during wort boiling

Fundamental changes during wort boiling

The wort after mashing and filtration needs to be boiled for 1-2 hours, and a certain amount of hops is added during the boiling process. The bitterness and aroma substances in the hops can be dissolved into the wort by boiling to give the beer a refreshing bitterness and a pleasant aroma. The boiled wort is called finalized wort.

Changes during wort boiling

1. Dissolution of hop bitter substances:

α-acids are not easily soluble in cold wort. Therefore, hops must be added when the wort is boiled to convert α-acids into iso-α-acids after isomerization. The iso-alpha-acid is easy to dissolve in wort, thus improving the utilization rate of hops.

2. Formation and isolation of coagulable protein-polyphenol complexes:

Thermal coagulation complexes do not dissolve when heated and are precipitated in the form of coagulation when the wort is boiled. These flocs formed by coagulation should be separated as much as possible. The cold-solidified complex is a complex formed by protein breakdown products and polyphenols in wort, which exists in dissolved form when the wort is boiled, and separates out in the form of cold solidified matter when the wort is cooled.

3. Evaporate the excess water to make the wort reach the specified concentration:

When the wort is boiled, the water evaporates, and the concentration of the wort increases accordingly. The content of bad flavor substances in the malt, wort and hops can be reduced through the evaporation of water.

4. Sterilize the wort:

Since the wort contains various harmful bacteria, if the wort is not sterilized, it will lead to rancidity of the wort. Therefore, by boiling the wort, various microorganisms in it can be killed.

5. Destroy enzyme activity and fix wort components:

The active enzymes in the wort can be destroyed by wort boiling, and the components of the wort can be fixed.

6. Wort color rise:

Due to the oxidation of melanoidins and polyphenols formed during boiling, the color of wort can increase.

7. Increased acidity of wort:

The acid melanoids formed during boiling and the acid substances brought by hops will increase the acidity of the wort.

8. Formation of reducing substances:

The process in which sugar reacts with amino acids, dipeptides or tripeptides is a Maillard reaction. Through the Maillard reaction, the amount of reducing substances in wort, such as melanoidins, dienols and dienols, increases.

9. Changes in dimethylsulfide content in wort:

When the wort is boiled, the precursor of dimethyl sulfide can be decomposed into free dimethyl sulfide, and this part of dimethyl sulfide and dimethyl sulfide from other sources can be evaporated together with the evaporation of water.

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