Brewing process hygiene plays a crucial role in the production of high-quality beer. Understanding the microorganisms present in the brewery environment and controlling microbial contamination are both essential to prevent spoilage of beer caused by microbes. Many common odors originate from contamination by wild yeast or bacteria, which can thrive in any small crevice or corner. Therefore, it is important to remember that everything can be a potential source of contamination, and thorough sanitation is necessary at every step of the brewing process, particularly during the cold end, such as in the fermentation tanks and hoses.
Pollution Source and Control Strategy in Beer Brewing Process
Contamination in breweries is typically categorized into primary pollution (during brewing) and secondary pollution (during bottling). While about 50% of microbial issues can be attributed to secondary pollution, the consequences of primary pollution are more severe. Beer spoilage microbes can appear at any stage of the process, while indirect spoilage organisms are the main contaminants. The putrefactive properties of a specific organism depend on its location in the process. Filtered brewer’s yeast is also considered a contaminant.
The primary contamination originates from yeast, wort, fermentation, and storage. Equipment used to ferment beer with cultured yeast is also a significant source of contamination. Fermenting yeast, dirty recycled bottles, and leftover beer are the most significant sources of contamination. Weak links in breweries that serve as sources of contamination include measuring instruments like thermometers and pressure gauges, valves, dead ends, gas lines, and worn floor surfaces. Contamination can also occur when hot wort is cooled in plate heat exchangers due to plate leakage, inadequate cleaning, or aeration. Contamination can also result from contaminated filter powder, dirty filters, or additives.
Secondary pollution originates from bottling, filling, or barreling in the brewery that has not undergone pasteurization. Any point of direct or indirect contact with clean or filled, unsealed bottles can be a source of contamination. Common causes of secondary pollution include sealing machines/caps, filling machines, the environment around sealing machines, bottle inspectors, and dripping water from bottle washing machines. Air pollution of beer can occur during the transport of corkscrews from the bottle washer to the filler until the bottle is sealed. The presence of beer spoilage bacteria in the air is associated with microbial spoilage issues in bottled beer. The highest concentration of beer-destroying bacteria is found near the filling machine.
Pollution Control Strategy
The best way to control microbial spoilage in beer is by eliminating sources of contamination:
- Improve beer’s resistance to microbial attack by adjusting pH, adding antimicrobial compounds, reducing water activity, increasing osmotic pressure, and more.
- Use processes that reduce microbial loads, such as filtration, high-temperature treatments (vigorous boiling, pasteurization, etc.), and storing at low temperatures.
- Design brewing and bottling equipment with hygiene in mind, including selecting appropriate materials, eliminating dead spaces, and minimizing rough surfaces.
- Physically isolate high-care areas where critical operations are performed and use barrier technology to prevent the entry of microorganisms from raw materials, people, and the air.
- Regularly and effectively clean and disinfect equipment and facilities.
Cleaning and Disinfection
The CIP (Clean-In-Place) procedure is used in closed brewing process lines. However, there may be a limitation in the CIP procedure due to the accumulation of microorganisms during equipment operation. Mechanical input is crucial for removing dirt and microorganisms. Open surfaces in breweries, such as bottle inspectors, filling machines, and conveyor chains in bottling plants, are often cleaned using low-pressure foam systems or film cleaning.
The use of hot solutions or strong chemicals is limited for safety reasons, but disinfectants that are effective under cold conditions can be used to ensure hygiene. It is recommended to use foam cleaning followed by disinfectant spraying after each production day, along with regular basic cleaning, including components that are difficult to inspect. However, care must be taken to avoid the spread of spoilage microorganisms through aerosols generated during pressure cleaning.
Regardless of the size of a brewery, it requires a process sanitation system that includes checklists, standard operating procedures, and audits. Adhering to high hygiene standards benefits both the perceived and actual quality of the beer. ACE engineers have provided valuable insights, and we hope this information can be helpful to you!
If you are planning to open or expand a brewery and need a turnkey solution for brewery equipment, feel free to contact us directly. Our engineers will design and manufacture brewery equipment tailored to your brewing process. We also offer customized solutions for brewery expansion.