Why count? (continued)

A great many people produce products successfully without counting cells at all. Success relies on extremely consistent processes, but is still subject to unforeseen factors.

Yeast slurries are often weighed in lieu of counting, however, weighing offers poor precision. By definition, a slurry includes a large proportion of water, perhaps hop matter and protein too, all of which is often a significant component of total weight. And to boot, any proportion of cells that are no longer viable, cannot contribute to fermentation.

For those who are willing to take the next steps, many benefits await...

• Perhaps foremost, there's good commercial sense.
• Quality assurance processes can offer confidence to both retailers and potential investors
• Consistent pitch rates contribute to consistent fermentations times, meaning a greater probability that the fermentor will be available for the next batch when expected
• Potential reduction in fermentation times by upto 48 hours with optimum fermentations, particularly with appropriate oxygenation (White and Zainasheff, 2010)

Fig. 1

• In an increasingly competitive market, creating a genuinely differentiable product is increasingly difficult. Where malt, water and hops are well exploited, yeast remains relatively unexplored.
• Pitch rate contributes to cell growth rates and in doing so, directly affect the magnitude of flavour production. For an increase of pitch rate, we would expect a decrease esters and increase of fusel alcohols.
• Whilst for common yeast strains (S04, US05 and so on) a typical pitch may be 5-10 million cells/mL, to add a Brettomyces component, the typical pitch would be closer to 200,000 cells/mL. For the former, we enjoy relatively wide margins for error before undesirable flavour thresholds are crossed. For Brett, less so, but that need not undermine the potential complexities that strain combinations can offer
• Similarly, a few hundred grams or millilitres here or there is of relatively little consequence on our production kits, but in our test batches and homebrews, this level of accuracy matters
• Whether we want a light spritz or cork popping fizz, we must fine-tune our secondary fermentation's fermentable sugars and pitch rate to produce exactly that carbonation
• The balance of broader fermentation conditions will drive levels of potential flavour compounds (see fig. 2). Cell interaction with hop acids will even affect IBUs.

Typical (min/max) levels of flavour compounds in beer
Fig. 2

• Fermentations are a balance of yeast strain, pitch rates, must/wort composition, temperature, dissolved oxygen, PH (see fig. 3) to name a few. CellMate assists in building a complete record of each fermentation.

Fig. 3
• Reproduceability - with two full data sets - a successful reference batch and a latest batch - we can see exactly where the differences lie and adjust accordingly.
• Scaleability - moreso than batch-to-batch consistency, reproducing a test batch on our full production kit is often challenging. For example, where we can deduce that hydrostatic pressure is slowing cell growth, we might choose to compensate with pitch rate or temperature

Why bother with automated counting?

• Foremost is improved productivity. Asking a winemaker or lab technician to count to 100 repeatedly is obvious under-employment, with a labour cost, but also the loss of time spent on higher value tasks.
• Add to that, the improvement of sanity gained by saving a person from this monotonous exercise
• Having reduced the effort intensive part of the exercise and added value by aggregating all of our data points, we can do more counts; counts that we would not otherwise have considered. In addition to a pre-pitch count, we could track cell growth throughout the fermentation life-cycle, especially for our force fermentations and test batches.
• Over time, the data collected will become a powerful production library, allowing the distiller to match achieved flavours with the fermentation profile used