Views: 12 Author: Site Editor Publish Time: 2025-08-26 Origin: Site
Brewing high-quality beer is a vibrant and pleasurable experience, one that integrates into the living world around us. Successful brewing is a result of the brewer's skill. The variety of microorganisms that enter beer during the brewing process and cause beer spoilage is as diverse as the beer styles themselves. They can impair the taste and aroma, cause turbidity, or form difficult-to-remove biofilms: beer spoilage bacteria and yeasts are a major challenge for breweries. However, regardless of the brewer's skill, they must establish a routine for regular microbiological testing throughout the brewing process. This is the only way to minimize batch losses.
Beer spoilage bacteria and yeasts are major problems for breweries. In principle, beer is not susceptible to microbial spoilage. Due to its low nutritional content, high alcohol content, high hop bitterness, high carbon dioxide content, and low pH, beer does not provide a favorable environment for most bacteria. However, some bacteria can adapt to these conditions. Non-alcoholic beers, hopped beers, and blended beers are more susceptible to microbial spoilage. Craft beers are particularly susceptible to microbial spoilage because they are often not pasteurized or sterile filtered.
Microorganisms and yeast | Feature |
Short lactobacillus | Lactic acid bacteria; makes beer cloudy and sour |
Pediococcus is harmful | Causes cloudiness and sediment and imparts a buttery flavor to beer; used intentionally in some beers |
Megasphaera | Produces cesspool and rotten egg odors |
tapeworm | Produces cesspool and rotten egg odors |
Diastatic yeast | Foreign yeasts are also used intentionally in some beers to create floral or bitter flavors. |
Pichia pastoris abnormalities | Yeast can cause cloudiness and flavor defects |
De Kela in Brussels | While Dekkera bruxellensis is an integral part of the aroma of many beers, Dekkera anomala is considered a deleterious yeast. |
Enterobacteriaceae | Produces odor; can also serve as an indicator bacteria |
Acetobacter | Produces odor; can also serve as an indicator bacteria |
Microorganisms have opportunities to inhabit surfaces of brewing equipment and even float in the brewery air. Without strict hygiene measures, these invaders can enter the beer during the crucial brewing stage.
Raw material quality is crucial in the brewing process; any imperfection can lead to contamination. Malt, hops, and water can all harbor spoilage microorganisms if contaminated. Water treatment is particularly important, as untreated water can introduce harmful components into the beer.
Maintaining brewing equipment in top condition is the cornerstone of preventing beer spoilage. Tanks, hoses, fermenters, and other tools must be rigorously cleaned and disinfected. Neglecting this critical step can create a breeding ground for spoilage microorganisms, which can then be transferred to the beer during the brewing process.
Maintaining precise temperature control during the fermentation process is crucial. Temperature fluctuations or improper control can create an environment conducive to the growth of spoilage microorganisms. Brewers must closely monitor fermentation conditions to ensure that only the yeast strain used to brew beer is effective.
Rapid detection of pathogens and spoilage microorganisms is a critical step in microbiology and the brewing process, as these microorganisms can negatively impact product quality. While beer remains popular, it must maintain extremely high quality to survive in a highly competitive market. Therefore, raw materials, intermediates, final products, surfaces, and specialized areas all require continuous monitoring through hygiene control programs.
Evidence suggests that up to 20-25% of craft beer may be contaminated with spoilage microorganisms, and some recent data even finds that spoilage microorganisms can be detected in pasteurized beer. As craft breweries grow and innovate, beer production increases, potentially leading to increased storage and shipping times for finished products.
Furthermore, increased production frequency places pressure on cleaning procedures. Monitoring site hygiene and product quality is crucial to meeting growing customer demands.
To be most effective in a brewery, BSM detection and identification methods must possess several characteristics. Most BSM detection and identification methods should be rapid, specific, accurate, quantitative, sensitive, and cost-effective. Even better, the method should be easy to use and require little to no training. Because raw materials and products move throughout the brewery, increasing the risk of contaminant spread, early detection is key to preventing problems from spreading and escalating. Furthermore, products with extended aging periods are particularly susceptible to low-level contamination. Therefore, a brewery's BSM detection/identification methods need to be sensitive to and provide results at low levels of contamination that can grow over time.
Because frequent, routine sampling and testing are key to early detection, even the smallest breweries must do so to prevent the financial losses caused by microbial contamination. Many craft breweries have limited budgets, so the method must also be affordable.
On-site testing technologies have been around for some time. Automated ATP (luciferase) assays are now commonplace, having proven their value over decades. While ATP analysis is highly reliable, the reagents used for ATP analysis are susceptible to degradation (false negatives) in the presence of certain detergents, particularly hypochlorite-based detergents. Furthermore, these reagents are non-selective and will adsorb any organism, potentially leading to false positive results. However, they cannot inform the winemaker of the specific spoilage organisms.