When designing the wort boiling time, the following basic factors are generally considered:
1. Various functional requirements for wort boiling must be guaranteed
★ What is more important is the isomerization of hops, the coagulation and precipitation of coagulable proteins, and the volatilization and removal of bad volatile flavor substances (such as DMS, aged aldehydes, etc.);
★ The second is the evaporation of excess water. It is relatively easy to kill the vegetative cells of microorganisms and passivate biological enzymes. If these basic requirements can be met in a short period of time, the boiling time can be shortened.
2. Consider the conditions of the boiler equipment used
The heating and evaporation structure of the boiling pot, the conditions under which the wort is uniformly heated, the state of the wort circulation, and the amount of evaporation in the boiling pot, etc. Different boiler equipment structures and conditions have a great influence on the determination of the boiling time. For example, Using modern new boiling equipment, the boiling time can generally be less than 70 minutes, and some boiling pots only need 50-60 minutes to achieve the effect of wort boiling.
3. Consider the quality and mash effect of various raw materials
Different raw material quality and mash effect will result in different wort composition. In order to make the shaped wort meet the needs of fermentation and product quality control, there will be different requirements on the determination of boiling time. If the malt quality is high and the saccharification effect is good, the wort boiling time does not need to be too long; if the malt quality is poor, the wort quality is also relatively poor, for example, the wort viscosity increases, boiling is easy to overflow, and the steam pressure control is relatively low. In addition, the saccharified wort obtained by boiling malt with high chroma should not prolong the boiling time as much as possible; wort with high DMS precursor content, and wort with high “nonanal potential” (large number of aged aldehydes), it is best to prolong the boiling time appropriately to enhance the boiling effect.
4. Consider the concentration of mixed wort and stereotyped wort
Consider the volume in which the wort is boiled. If the concentration of the filtered mixed wort is low and the volume of the wort is large, in order to ensure the uniformity of the wort heating and meet the requirements of wort concentration, it is generally necessary to strengthen the boiling or add a certain amount of extract to increase the wort concentration. Otherwise, the boiling time needs to be extended; to produce a higher concentration of stereotyped wort, in addition to increasing the concentration by adding extracts such as syrup, a longer boiling time is often required.
It should be noted that after determining the appropriate wort boiling time, it must be kept relatively stable and should not be extended or shortened arbitrarily. This is because the determination of the boiling time also determines the method and quantity of wort washing, the steam conditions used, the way of adding hops, etc. Arbitrary changes in boiling time may lead to instability in wort composition and wort quality.