Brewing groups such as Coors, Interbrew, Heineken, Diageo, Scottish & Newcastle and Anheuser Busch are able to produce more consistent fermentations by using Aber Yeast Monitor probes to dose the exact amount of yeast in at the start of each. According to John Carvell, Sales and Marketing Director for Aber Instruments, "The Yeast Monitor is now regarded as the standard in many of the international brewers for automatic yeast dosing. In many cases, automatic pitching systems based on weight or on optical sensors in the wort main have been replaced by using the Yeast Monitor with a probe placed in the yeast slurry main. The company’s instruments for measuring live cell concentration on-line are now used in over 400 brewing and biotechnology plants world-wide."
A further advance in the Yeast Monitor becoming the standard in the industry has come with the launch of new range of Model 700 series Yeast Monitors. The new Yeast Monitors are up to 50% lower in cost compared the earlier models and the instrument has the flexibility of being able to monitor both thick yeast slurries and the lower cell concentrations found in fermentation and propagation. The new range has already been purchased by Coors in the UK and USA, Heineken and Diageo but in some cases these have been installed to replace the original Yeast Monitors that have been operational for more than 10 years. Sales have not been to just to the large breweries: Chimay, Belgium, has commissioned a system for consistent yeast dosing during secondary fermentation.
The instruments use the principle of "radio frequency impedance" for an accurate measurement of the live yeast cell concentration. Unlike many optical probes, the Yeast Monitor can be used in thick moving yeast slurries and the system does dot respond to varying levels of trub. At the heart of the system is an in situ, robust, probe that can be cleaned in place or steam sterilized and requires minimal maintenance.
The new Yeast Monitor range has incorporated some of the latest manufacturing techniques that allows a high specification instrument to be manufactured at a lower cost. The Yeast Monitor Model 720 has an integral multiplexer, allowing the unit to be expanded up to 4 channels and it is completely contained within a stainless steel IP65 enclosure. The Model 710 is a budget single channel instrument, ideal for a dedicated yeast pitching or cropping applications requiring only one probe. Communication options include separate 4-20mA outputs for live cell concentration and conductivity and options for Profibus and other fieldbus communications to the PLC.
Applications with Yeast Monitor are not restricted to just yeast pitching and fermentation monitoring. Several of the major brewing groups have shown that considerable cost savings can be made by using the Yeast Monitor to monitor and even control the cropping process. With often multiple cropping lines, the Yeast Monitor provides a complete history of the yeast recovery process and will provide alerts when the critical stages of the transition form yeast to beer have been reached. Moreover, the Yeast Monitor will also then be able provide final concentration of live yeast in each storage tank.
Installing a Yeast Monitor in a brewery can also provide some significant cost savings and this data was presented as a poster at the IBD Asia Pacific Convention in Tasmania in March 2006. Copies of the posters are available on request.
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