“PROFI® will replace kieselguhr filtration across a broad front” - practical experience of the Carlsberg brewery
In 2005, the Carlsberg Group was the first brewing Group with world-wide operations to decide to use kieselguhr-free PROFI® filtration. The separator/membrane filtration line was installed at the Fredericia brewery in Denmark, and was initially operated as a test installation in parallel with the existing kieselguhr filtration system.
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It was possible for the results to be compared continuously and on a representative basis. A tough test at the highest level: this is because the kieselguhr installation had already been optimised with regard to its water and kieselguhr consumption. Nevertheless, it quickly became apparent that Carlsberg would no longer return to kieselguhr filtration.
The advantages of PROFI® at a glance
- As the end product, the installation provides an absolutely reliable and in particular constant quality right through to the finest aroma nuances.
- Because the installation operates completely without any kieselguhr, the entire kieselguhr handling process is no longer applicable.
- The installation provides completely retentate-free operation without any circulation tanks; this has a positive impact on investment costs, energy input, process reliability as well as beer or extract losses.
- No mixed beer is obtained when the system changes over from one type of beer to another; this virtually eliminates beer losses.
- And, which is of course one of the most important aspects, there are no significant sensory or chemical differences compared with the kieselguhr method.
The process lines in detail
Two PROFI® lines with an hourly capacity of 400 hl each are now operating in Fredericia. The installations have thus filtered several million hectolitres of beer so far. Based on this experience, a genuine benefit of the PROFI® filtration is that it provides genuinely continuous operation. For instance, four membrane blocks are installed at Fredericia, and three of these blocks are always operating. If one of these membrane blocks reaches maximum transmembrane pressure, it is taken out of operation and the system switches over to the stand-by block. For this purpose, the installation fills the previous stand-by block with beer, switches it over to filtration, discharges the previous production block, takes it out of the filtration process and switches it to the cleaning cycle. As is the case with the filtration result itself, this fully automatic filtration process is extremely reliable.
Process line for PROFI® system
“With PROFI® you know in the evening precisely what beer will be in your tanks the next morning.”
This is how the system was described by one of our employees. This situation is not always applicable for flotation filtration, in which parameters such as the regular dosage or flow have frequently to be fine tuned. And then there is the problem of malfunctions.
From the point of view of Carlsberg, the next key advantage is the flexibility of PROFI® filtration. At Fredericia for instance, the entire range of beers is filtered. This range includes light Lager beers right through to stouts and strong beers, whereby all types are high-gravity beers.
For Carlsberg therefore, it is tremendous progress that PROFI® enables the system to be changed over to a different beer type extremely quickly and without significant quantities of mixed beer. When the system changes over to a different beer type, it feeds the beer from the separator into a buffer tank which is installed between the separator and the membrane filter block. The system then carries out water rinsing and switches over to the next beer tank. In parallel with this process, the membrane block also discharges the beer into the buffer tank. The membrane block is then rinsed with water, emptied with CO2, and the filtration process for the new beer type then commences. Even when the system changed over from stout to Pils, there were no signs of any change in colour in the Pils despite the fact that the system had not been rinsed with water.
PROFI® therefore permits very short change-over times and very low volumes of mixed beer. The system design is also a major factor in this respect. The membrane block empties completely as a result of its design. At the same time, the volume within the system is very small compared with other membrane blocks. This is also an explanation why PROFI® is much more flexible than kieselguhr filtration or other membrane systems.
Side effect: more cellar capacity
A further positive side effect must not be forgotten: before using PROFI® filtration, Carlsberg had a normal cold beer process at Fredericia, consisting of fermentation cellar, followed by clarification by means of separators, then a storage cellar with cold maturing and finally filtration in the pressure tank cellar. In the current solution, the beer is channelled directly into the pressure tank cellar via PROFI® filtration. In this way, six large tanks which previously were required for cold storage can now be used for fermentation by Carlsberg. The process times have also been reduced. Carlsberg has thus increased its cellar capacity without having to invest in additional tank volume. This was made possible by the excellent function of the PROFI® separator, which clarifies the young beer directly down to the point at which it is suitable for the membrane filters. The separator is thus an extremely important, and may even be the crucial, guarantee of success for membrane filtration of beer. This is because, whatever happens, it always removes all substances which might damage the membrane.
Conclusion
There is no doubt that PROFI® will replace kieselguhr filtration across a broad front. From the point of view of Carlsberg, it has been better for a long time. And it also offers further major potential for improvement of around 25 per cent in terms of costs and the capacity of a line.
Information about the author: Peter Rasmussen
Deputy Production Manager
Carlsberg Fredericia Brewery
Denmark
Photos (except machines): Carlsberg Breweries A/S