The Process of Beer Sterilization

In the process of beer sterilization we should pay attention to the following problems in controlling the sterilization process of beer: 

1. The temperature of the sterilization hot water should be higher than the beer sterilization temperature by 2~3 °C, otherwise it will affect the speed and heat transfer effect of heating beer, but this temperature difference should not be too large to prevent local overheating.  

2. It is necessary to maintain the stability of the temperature of the three temperature zones of heating, sterilization and cooling, and the amplitude of temperature change should not exceed 5 °C in the heating and cooling zone, and should not exceed 2 °C (±1 °C) in the sterilization zone.  

3. The temperature and time of beer in the sterilization area must be correctly controlled. If the sterilization temperature is too high, first, it will not only cause the unstable polymer protein contained in the beer to coagulate and precipitate, forming a trace of flocculent; Second, it will intensify the oxidation of oxygen on beer components, such as oxidizing polyphenols and some flavor components, so that beer produces astringency and aging taste, and may make the color of beer darker, and high temperature will also reduce the solubility of CO2, and a large amount of CO2 overflow will cause the pressure in the bottle to rise sharply and cause the bottle to burst, increasing the bottle damage and wine damage. If the sterilization temperature is too low, the sterilization effect will not be achieved, causing biological turbidity. Therefore, the water temperature in the sterilization area should be controlled at 62±1°C. In addition, the control of the sterilization zone time is also very important, according to the theoretical requirements, the effective sterilization time of beer is 60 °C, 6min, considering the heating time required after the bottle beer enters the sterilization zone from the heating zone (35~40 °C) and the heat transfer speed of the glass bottle and the static beer, the actual residence time in the sterilization zone is 20min.  

4. The heating of beer should be gradually increased, and the filling temperature (4 °C) should be increased to the sterilization temperature (60 °C) should be divided into at least three sections, that is, from 4 °C to 30~35 °C, and then to 50~55 °C, and then to 60 °C for heat preservation and sterilization, the heating speed is too fast (or the temperature of heating beer is too high), which will not only make the temperature difference between the outside and the inside of the glass bottle too large, exceed the temperature difference tolerance range of the bottle, cause the bottle to break, and make the temperature difference between the center of the bottle and the edge of the bottle too large. A thin layer of turbulence is formed, which affects the heat transfer of beer. The cooling of beer should also pay attention to gradual cooling, otherwise it is also easy to cause bottle bursting, but the cooling rate can be slightly faster than the heating, so as to avoid excessive oxidation of beer in a higher temperature state for a long time.  

5. In the pasteurization process in actual production, the time is often relatively long, because the filling temperature of beer generally does not exceed 4 °C, so that the pasteurization process in production includes 8 stages of gradual heating from 4 °C to 60 °C, heat preservation at 60 °C, and gradual cooling from 60 °C to 30~35 °C, and the total time takes about 1 hour.