Wort boiling is an important process that occurs in the brewing kettle. The quality of the boiled wort plays a significant role in determining the final quality of the beer. Therefore, in addition to designing the brew kettle properly, how can we effectively control the wort boiling process?
In order to determine the boiling time for the wort, it is necessary to take into account the wort concentration and adjust the boiling intensity accordingly. This will help achieve the desired final wort concentration within the prescribed boiling time.
The boiling time of the wort has a significant impact on the characteristics of the beer. When boiling at normal pressure, the boiling time for light beer (10% ~ 12% concentration) is generally controlled between 1.5 and 2 hours, while for thicker beer, it can be extended appropriately. When boiling under specific conditions, the boiling time can be shortened by approximately half.
Reasonably extending the boiling time is beneficial for protein coagulation, improving hop utilization, and reducing the formation of unwanted substances. However, it may negatively affect foam performance. Excessively prolonging the boiling time is not only economically unreasonable but also leads to a decrease in wort quality. For example, it can result in dark wort, a rough taste, reduced bitterness, and poor foam, especially for light beer.
The boiling strength corresponds to the amount of water evaporated per hour, expressed as a percentage of the mixed wort. It is closely related to factors such as thermal conductivity, shape, heating area, steam pressure, evaporation area of the wort, and boiling method used in the kettle.
The pH value of the wort is closely related to protein coagulation, wort color, and flavor.
Proteins in the wort are most unstable at their isoelectric point, leading to their coagulation and precipitation. Each protein in the wort has a different isoelectric point, resulting in precipitation occurring at different pH values. The ideal pH value for wort boiling is 5.2, but achieving this value under normal conditions is difficult, particularly when using hard water for saccharification. Generally, acidification is used during the start of acidification or when boiling the wort to lower its pH value. A pH range of 5.2 to 5.6 is usually sufficient for protein coagulation. The better the protein coagulation, the greater the stability of the beer.
It is ideal to maintain the pH value of the wort within the range of 5.2 to 5.4.