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Cheers to reliable yeast cell counting!

Published 1 November 2023 by Sean Butler

The importance of reliable yeast cell counting in breweries

In the world of craft brewing, where creativity and precision converge, every element counts. Among the crucial ingredients, yeast plays a role so significant that it can make or break a batch of beer. Yeast is the unsung hero of brewing, responsible for the fermentation process that transforms wort into beer. To ensure the quality and consistency of your beer, reliable yeast cell counting in breweries is a fundamental practice that should never be overlooked.

Before delving into the importance of cell counting, let's understand why yeast is so crucial in brewing. Yeast is a microorganism that consumes sugars from the malted barley, producing alcohol and carbon dioxide as byproducts. This fermentation process not only imparts alcohol content to your beer but also influences its flavour, aroma, and overall quality.

Yeast comes in various strains, each with its unique characteristics, contributing to a wide range of beer styles. Whether you're crafting a crisp pilsner, a robust stout, or a fruity IPA, choosing the right yeast strain is a critical decision for brewers. However, achieving the desired beer characteristics depends not only on selecting the right yeast but also on maintaining the yeast's health and vitality throughout the fermentation process.

Reliable cell counting is the practice of quantifying yeast cell concentrations at various stages of the brewing process. Here are some key reasons why this practice is essential in breweries:


Consistency is the hallmark of any great brewery. Whether you're a homebrewer or a commercial brewery, producing the same quality and flavour profile batch after batch is crucial. By accurately counting yeast cells, brewers can ensure that each batch of beer is produced with the same yeast cell density. This consistency leads to consistent fermentation, which in turn results in a uniform flavour profile, aroma, and alcohol content in every batch. Profiling yeast also enables brewers to select strains that exhibit predictable fermentation behaviour, ensuring that each brew meets the desired specifications.

Adaptability to brewing conditions

Yeast strains also exhibit different temperature ranges and fermentation rates. Some strains thrive at warmer temperatures, while others prefer cooler environments. By knowing the optimal conditions for a particular yeast strain, brewers can create an environment that maximises its potential, resulting in a cleaner and more consistent fermentation process. 


Accurate cell counting ensures that you use the right amount of yeast for each batch. Over-pitching (using too much yeast) can result in unnecessary expenses, while under-pitching (using too little yeast) can lead to incomplete fermentation and off-flavours. Proper cell counting optimises yeast usage and reduces production costs, so investing in a proper method will be much more beneficial in the long run.

Recipe development and managing flavour

Experimentation is at the heart of craft brewing. Certain yeast strains may produce unwanted compounds, such as diacetyl or sulphur compounds, which can negatively impact the beer's flavour and aroma. Through yeast profiling, not only can brewers can identify strains that are less prone to producing these off-flavours, but can also fine-tune recipes and create unique flavour profiles by adjusting yeast cell concentrations for different beer styles. And lastly, unhealthy or stressed yeast can produce off-flavours and aromas, affecting the beer's quality. Regular cell counting helps identify issues early and take corrective measures to maintain yeast health.

Shelf life

Yeast cell counts also play a role in a beer's shelf life. By understanding the yeast's contribution to stability, brewers can make informed decisions about how long a beer will stay fresh and drinkable.

How to count yeast cells

Reliable cell counting is not a mere technicality but a critical component of brewing. It underpins the consistency, quality, and efficiency of the brewing process while enabling brewers to create distinctive flavours and maintain yeast health. Therefore, it is critical that a brewery makes the correct choice when deciding on which method to use.

Yeast cell counting can be carried out using various methods, such as hemocytometers, flow cytometers, and perhaps most accurately by use of cell counters - such as the CASY® cell counter.

The CASY is the ultimate tool for not just counting overall yeast numbers, but also profiling which species are present based on their size. This allows full oversight of yeast profiles throughout the whole brewing process to keep this crucial factor consistent between batches. Yeast profiles can change over the years leading to that signature taste changing too – the CASY is the perfect tool to monitor this change and allow intervention to be made to maintain the ultimate brew! 

The CASY makes the whole process easy – with no need for dyes, a count can be taken within 25 seconds and gives information on cell concentration, viability, volume, size distribution, aggregation, debris and biomass.

So next time you're enjoying a refreshing pint, remember that reliable cell counting had a huge part to play in bringing that beer to life. Cheers to CASY technology!