Wort boiling operation technology

Wort boiling is a key step in the beer brewing process, and this process has a significant impact on the properties of the final product. The wort boiling operation technology mainly involves many issues such as boiling time, boiling intensity, hop addition, additives, wort concentration, pH value and the composition of finalized wort.

〖Boil time〗

After the wort enters the boiling pot, it starts to heat up for boiling. Usually, the boiling time is calculated after the temperature of the wort reaches 100 °C. Of course, the boiling time of the wort should be specifically determined according to the variety, process and quality requirements of the beer. Reasonably prolonging the boiling time is beneficial to the coagulation and precipitation of protein, improving the utilization rate of hops and the formation of reducing substances, but it is not conducive to the foam performance; excessively prolonging the boiling time will not only consume a lot of energy, but also reduce the quality of the wort. Therefore, the boiling time of general wort is about 70~90min.

〖Boiling strength〗

The boiling process can be divided into three stages, namely preheating, initial boiling and boiling

01 warm up

Start preheating after the filtered wort has passed the heater surface (or heating belt), and the amount of steam at this time is smaller. The purpose of the preheating process is mainly to prevent the temperature of the wort from cooling down naturally during the filtration period, so that the temperature will drop. Or preheat with hot water through a thin plate heat exchanger.

02 Initial boiling

That is, the wort is near the early stage of boiling, the initial boiling time should not exceed 30min, the steam volume at this stage has not been fully opened, the steam volume is not very large, and the washing process is still in progress. The function of this stage is to prepare for evaporation. Once the washing is completed, it can enter the boiling and evaporation stage immediately.

03 boil

At this stage, the steam volume is turned to the maximum, so that the wort can maintain a vigorous boiling state. The quality of boiling has a significant impact on the clarity of the wort and the nitrogen content of coagulation. It is usually evaluated by the boiling intensity.

Calculation of boil strength

Boil strength is the percentage of evaporation per hour of the blended wort. The calculation formula is:

Boiling strength (%, h) = (mixed wort amount - final wort amount) / (mixed wort amount × boiling time (h)) × 100%

The boiling strength is generally between 8% and 12%. Of course, this needs to be determined according to the material of the equipment, the heating form, the heating area and the requirements of the type of beer.

The effect of boiling intensity

The high boiling intensity is conducive to the coagulation and precipitation of protein, which can better remove some unfavorable flavor components, shorten the boiling time of wort, improve the utilization rate of hops, and ensure that the final wort is clear, transparent and of high quality; but the boiling intensity is too high, If the tumbling is too violent, it will strengthen the oxidation, make the color of the wort darker, reduce the reducibility, increase the volatilization loss of hop oil, lack of hop aroma, etc., and also destroy the formed flocculent thermal coagulation; if the boiling strength is insufficient, Then the protein coagulation and precipitation are incomplete, the utilization rate of hops is low, the water evaporation is small, the boiling time is long, the bad smell in the wort cannot be evaporated, the decomposition of the dimethyl sulfide (DMS) precursor is incomplete, or the DMS cannot be effectively volatilized. Removed and stored in the wort, it is easy to bring unpleasant flavor to the beer.