Yeast pitching/dosing

Historically, yeast has been pitched into fermentation vessels based on mass or volume, and adjusted according to sample viability. This method may result in highly variable and unpredictable fermentation times, large batch-to-batch variation and inconsistent product quality. This is the experience of many breweries today. The key objectives for any brewery is maximising product throughput and making the most efficient use of fermentation vessels. This may be achieved in two ways, firstly reducing the end of fermentation (EOF) time by consistently achieving the correct target pitching rate concentration, and secondly, reducing process variability and improving consistency with regards to EOF times to aid in planning. This is where the Aber systems come in…

Underpitching can lead to stalled/hung fermentations. Overpitching can produce off flavours and haze.

The automatic pitching rate control system ensures that an accurate amount of viable yeast slurry is delivered from a Yeast Storage Vessel to the Fermentation Vessel within a defined period. Once the brewer sets the target amount of yeast required, the Aber Yeast monitor can help pitch the exact amount of viable yeast in the fermenter.

During pitching, the system monitors the concentration of viable yeast passing the probe in the pitching main. The resulting signal is then integrated with the output from the flow meter, giving a measure of the volume of viable yeast pitched into the fermentation vessel. When the target is reached the controller will turn off the yeast pump.