Beer Recovery
All good things come in threes: Separator, decanter, membrane filtration
More and more breweries are investing in beer recovery – for good reasons. This improves their cost-effectiveness without changing the beer quality. Indeed, the yeast and tank bottom volume accounts for approx. four percent of total annual output, and of this figure approximately 60 percent can be recovered in the form of beer. At a brewery with an output of one million hectolitres, this corresponds to a volume of 24,000 hectolitres. Which of the three possible systems (separator, decanter and ceramic membrane filter) is used in a specific application depends on the particular circumstances of the brewery. However, it is certain that GEA Westfalia Separator is the only provider to make all three process alternatives; this means that it is able to provide neutral advice and make recommendations which are suitable for each specific operation.
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Easy process management with separators
The separator represents the most simple process solution with minimum investment costs. With its continuous process, the process time is only 120 seconds; the yeast is accordingly exposed to very gentle treatment. On the other hand, production times are long:
The separator is subject to standard CIP only every 72 hours. The GSC 150 separator, which is specifically suited to this task, ensures that the yeast is treated to a dry matter content of around 25 percent thanks to the Westfalia Separator® hydrostop discharge system. The hydrohermetic inlet ensures gentle treatment of the product. Depending on throughput, the recovered beer still contains around 0.1 to 2 million cells per millilitre. The hydrohermetic seal also prevents the product from coming into contact with external air, and guarantees absolutely wear-free operation.
With the GSC 150 separator, it is possible for beer to be recovered from yeast and also for the green beer from the fermentation tank to be clarified following the addition of yeast upstream of the separator. In the feed, the yeast concentration may be max. 40 percent (by volume).
Processing with separator
Decanter technology for larger breweries
For larger breweries in excess of approx. two million hectolitres beer output, decanter technology is the most cost-effective solution. In the same way as the separator, the CB 506 fully hydrohermetic decanter developed specifically for beer recovery operates continuously, and can also adapt fully automatically to changing feed parameters by means of a density measurement facility in the feed. This means that the feed quantity can fluctuate between 20 and 40 hectolitres per hour, and that the solids content in the feed may fluctuate between 5 and 70 percent (by volume). This always produces a yeast with a dry matter of between 24 and 27 percent and a residual content of yeast in the recovered beer of less than 1 million cells per millilitre. The hydrohermetic discharge and the immersion of the solids side prevent any oxygen absorption. The decanter has also been designed in accordance with hygienic design guidelines and thus facilitates CIP cleaning.
Beer recovery with decanters
Decanter plus polisher
It is possible to further improve beer recovery by means of a decanter by combining a decanter and separator or connecting a decanter and separator in series. The yeast is initially concentrated by the decanter to a maximum dry matter of 25 to 28 percent, thus achieving an optimum yield. The beer which is recovered from the decanter is then processed further in a small polisher from around 1 million cells per millilitre to fewer than 1000 cells per millilitre. The beer which is treated in this way is solids-free.
Processing with decanter and separator
Nozzle separator for small feed fluctuations
The fourth alternative is the nozzle separator GFE 45 with the “Westfalia Separator® viscon®” system. These relatively small, fully automatic units operate continuously and utilize an energy-saving drive. GEA Westfalia Separator has developed a service-friendly concept by fitting the nozzles in the bowl head. In contrast to conventional separators, the “Westfalia Separator® viscon®” nozzles are not located at the bowl periphery but on a smaller diameter in the bowl where the pressures are substantially lower. By this means, the separated cells are exposed to significantly lower shearing forces. Thanks to the hydrohermetic feed, which ensures a low oxygen intake, and the discharge through the “Westfalia Separator® viscon®” nozzles the shearing forces are reduced to a minimum. The “Westfalia Separator® viscon®” nozzles enable adjustment of the discharge concentration of the concentrate phase to a virtually constant value despite fluctuating feed rate and concentration.
In addition to the nozzles, an ejection system is integrated. By this means, it is no problem to react to sudden pressure peaks. As a result of the concept of configuring the solids discharge variably only within certain limits, the yields can vary enormously. In the case of increased solid volumes in the feed, dilution can take place; in the case of excessively low values, the losses increase because of the way the system works.
The nozzle separator is particularly suitable as an alternative when only small fluctuations are to be expected in the volume to be processed and the solids concentration. The investment costs are lower than with other systems but the return on investment takes a little longer.
The result of beer recovery with a nozzle separator is yeast with a dry substance content of 18–20 percent and a residual content of below 1 million yeast cells per millilitre.
Beer recovery with nozzle separator