In general, the timing starts when the wort temperature reaches 100°C. Of course, the total boiling time should depend on the type of beer, brewing technique, etc. Typically, the boiling time is about 70-90 minutes.
There are three main boiling processes. Preheating, primary boiling and boiling.
Preheating Generally speaking, when the released wort is submerged in the heating device, the flow of steam is low at this time. As we all know, the temperature of wort will slowly decrease during the pulling process, and if we start heating after the pulling is completely finished, it will take longer time before boiling. Therefore, preheating will help to keep the temperature warm or raise it slowly.
2.Primary boiling It means that the wort is just boiling, no more than 30 minutes at a time. Now the steam valve is not fully opened and the release of wort is still in progress. This stage is to prepare for evaporation. Once the dosing is finished, evaporation can start.
Boiling The steam valve is now fully opened and the wort continues to boil. The quality of boiling is mainly judged by the boiling intensity. Generally speaking, the boiling intensity is between 8-12%. In the actual beer brewing process, there is also an estimate that for 1000 liters of wort, the evaporation should ideally be between 1.1-1.4 liters/minute.