In the beer brewing process, biological stability treatment is a link that cannot be ignored. Although the wort at the end of boiling is sterile, harmful microorganisms may still enter the beer due to an unclean working environment or improper operation. (Of course, not all microorganisms that enter the wort or beer in any way are harmful bacteria for beer.) The most unwelcome harmful bacteria in beer that are easy to appear are:
- Wild yeast, such as diastatic yeast (Saccharomyces diastaticus), pasteurian yeast (Saccharomyces pastorianus)
- Lactobacillus brevis and Lactobacillus frigidus, Pediococcus damnosus, and other harmful bacteria for beer.
These harmful bacteria reproduce themselves and form precipitation in beer, causing it to be turbid. In addition, some bacteria are anaerobic bacteria, which can reproduce in anaerobic beer after filling, bringing a metabolite with a sewer-like smell, making the beer undrinkable.
The practice has shown that factors such as unclean brewing environment, overloaded operation of beer filtration equipment and high-temperature storage will affect the biological stability of beer. Therefore, keeping the brewing environment clean and the equipment hygienic is the basic principle every brewery should strictly follow. “In all departments of the brewery, thorough cleaning comes first!” This sentence applies at any time and any place.
Overall, the hygiene habits of brewers have the greatest impact on this problem. Microorganisms can enter the beer from the staff’s clothes, or harmful microorganisms are not removed due to the workers’ insufficient work (such as incomplete cleaning). To prevent microorganisms from entering the beer, brewers should pay attention to the following points:
- Strictly abide by the cleaning and sterilization rules formulated within the company.
- Comply with hygiene regulations and do a good job of personal hygiene.
- Remove all dirt and attachments on the tank wall, and pay special attention to some gaps and grooves.
- Disassemble, clean, sterilize, and lubricate the plug valve and sampling valve with silicone oil.
- Brush and sterilize the glass sight glass and hose.
- Wear rubber shoes first when cleaning the fermenter, and then clean them.
- Regularly check the effectiveness of cleaning agents and disinfectants to eliminate all sources of contamination.
If all employees in the brewery can follow these guidelines, the brewery will take an important step in improving the biological stability of beer. Of course, when the beer is contaminated, the brewery needs to find out where the contamination entered the beer, and these sources of contamination must be completely removed or safely handled. The brewery also needs to focus on the location where the contamination occurred and take effective measures to control it. Monitoring the production process and ensuring the stability of beer are important tasks for brewery microbiological testing, which has also led to the emergence of processes such as pasteurization, flash sterilization, aseptic filtration, and filling.
