Brewing control systems: microbiological analysis

The presence of inhibitors, such as hop compounds, alcohol, carbon dioxide, and sulfur dioxide, as well as the shortage of nutrients and oxygen and the low pH make beer resistant to microbial contamination. Moreover, processes such as filtration, storage at low temperatures and possible pasteurization reduce contamination. The special environment in the brewing process restricts the range of microorganisms likely to be encountered to relatively few species. Although the contaminants found may cause quality defects, pathogens have not to knowledge been reported to grow in standard beer products. Ensuring the well-being of the production, yeast strains is a fundamental part of brewing as in all processes based on fermentation technology. Thus, monitoring yeast quality and quantity is also an important part of the microbiological control carried out in breweries. This chapter presents a summary of the microorganisms likely to be encountered in breweries and the different possibilities to detect and identify them. It also describes the different possibilities to quantify yeast mass and estimate the brewing performance as well as differentiate between yeast strains and discusses both methods currently in use and emerging technologies. The chapter reviews those methods that show most potential for brewery applications till date.