Analysis Request – Beer

The mechanics behind brewing a quality beer involve both chemistry and microbiology. Standard steps from one brewery to the other in the beer brewing process include malting, milling, hop additions and boiling, fermentation, aging and maturing. Getting the right balance of microbes throughout these processes is essential to successful brewing. Microbes, although necessary, may also negatively impact the brewing process from fungus causing damage to barley, to Lactobacillus spp. causing off flavours and aromas in your finished products. While various chemicals may treat these problems it is often preferred to meticulously monitor, and control microorganisms present throughout the entire brewing process.


A successful fermentation starts with healthy and happy yeast. Before pitching yeast or when fermentations slow yeast cell counts and viabilities are recommended. Throughout the brewing process viable yeast and bacteria can be both detected and quantified through yeast or aerobic or anaerobic bacteria culturing.


Some of the main characteristics in beer are determined by the crucial role microbes play in the beer brewing process. The appearance in terms of turbidity and colour, the palate due to carbonation, and the flavour and aroma profile are determined by the presence of various yeasts and bacteria throughout the brewing process. That being said, the presence of unwanted microorganisms at crucial stages in the brewing process may result in unwanted pH changes, gushing, overattenuation, haze, biofilms and off aromas.

How often?

Yeast cell counts, viabilities and microscopic identification should either happen in-house or through an external laboratory before pitching yeast. Testing of the fermenter after wort transfer, the yeast slurry and the finished products should happen on a regular basis providing you with the ability to determine exactly where contamination has taken place when and if it occurs.


Brewing samples should be monitored throughout the entire brewing process ensuring the process is contaminant free. Cell counts and viabilities are beneficial before pitching, but other process control samples include wort, tank, post-fermentation, maturation, and packaged beer samples.


Microbial stability impacts everyone involved in the brewing industry, from small scale home brewers to commercial Brewmeister’s.