The „Mönchshof“ brand is a great success story. To ensure that it remains on a solid technical footing in the future, Kulmbacher Brauerei AG has invested in a new blending plant for the Mönchshof product line and is relying on know-how from Hofheim am Taunus. With many years on the market, the brand has now become the Franconian brewery‘s flagship product throughout Germany and beyond. In order to meet the challenges in production and the high quality requirements of the product itself, an investment was made in an in-line mixing plant including process integration at the Kulmbach site for the 2021 summer season.
Anyone who has never been to Kulmbach themselves will at least have heard of their beer. Since the discovery of the Kasendorf beer amphora, the Upper Franconian district town has been regarded to this day as the cradle of beer brewing on German ground and therefore refers to itself with a twinkle in its eye as the „secret capital of beer“. Even non-experts will immediately notice that beer brewing runs like a thread through the history of the city at the confluence of the Main River. The breweries of Kulmbach had already achieved a considerable output by the end of the 19th century and, with the connection to the newly developed rail network of the King Ludwig North-South Railway, had ideal conditions for exporting beer. The city‘s major brewers were Sandler, Reichel, Mönchshof and the Erste Kulmbacher Actienbrauerei (EKU). After the years of consolidation and the reestablishment of Kulmbacher Brauerei AG from the merger of EKU and Reichelbräu AG in 1996, the preservation of the brewing tradition and the production of beer specialties are still the top priorities today. The fact that this is no coincidence is shown by the rapid growth in total output in recent years, especially of the Mönchshof brand. After completion of the merger, the first thing to be done was not only to merge the two breweries in the economic sense, but especially on the technical side. Reichelbräu, located on the southern side of the white Main River, which is also called the Mühlbach in Kulmbach, and EKU, north of the river, were connected by a pipeline. The demolition of the old brewhouse and the construction of a new one on Lichtenfelser Straße marked the start of the process of merging the two breweries into one brewing operation. Temporarily, the former EKU brewery on Gummistraße served as a replacement facility. The previously newly added filter cellar provided the flexibility to prepare the abundance of varieties for bottling. After completion of the top- and bottom-fermenting fermentation and storage cellar, beer production at the former EKU site was discontinued and the site has since been supplied from Lichtenfelser Strasse via the named pipeline. In addition to continuous improvement measures and the expansion and modernization of the bottling plant in the 2010s, process-related investments were also made. True to the motto „a brewer who does not construct, soon might be bankrupt“ has always been diligently created what is necessary and possible to keep the location and the quality at the highest level.
Mönchshof success story and its technical production consequences
The beer specialty from the swing-top bottle is now one of the most popular beer brands in Germany. The product range and brand image are distinctive and at the same time traditionally regional. Since the switch to the swing-top bottle and the consistent expansion of the brand image, the annual production volume has risen steadily and in the pandemic year 2020 even exceeded the volume of 1 million hectoliters. This is particularly due to the fact that the top sellers in the range are the „Mönchshof Radler“ and „Mönchshof Radler Alkoholfrei“ variants. In line with the trend, the „Mönchshof Naturtrüb‘s Alcohol-free“ variant is also part of the success. A circumstance that also had to be followed on the technical and technological side:
„We have been producing mixed beer beverages for over 20 years. We started with shandy and cola beer, and the lemonade components were always delivered to us in tankers by our mineral water company Bad Brambacher. Mixing was done classically and rather manually by pumping into a pressure tank,“ explains Martin Sack, head of production at Kulmbacher Brauerei AG.
The contract filling operations that had to be carried out in the meantime also involved a great deal of extra work. For example, the circumstances surrounding container filling and emptying, without any additional loss of quality.
Last but not least, in order to meet the increased demand resulting from the success of the product, it was necessary to upgrade the process technology to the latest state of the art. The capacity of the existing blending plant alone was no longer sufficient, especially during the summer months. In the future, another filling line for swing-top bottles will start up at the site, so that at the latest then no peak loads will have to be cushioned by possible pre-production on pressure tanks.
Martin Sack explains the problem as follows: „Our mixed beer beverages are produced exclusively with sugar-limo and the turbidity is managed by using beers clouded with yeast. If the mixed beer beverages remain in the pressure tank for a longer period of time, the yeast can settle and secondary fermentation can occur. Thus, only smaller batches can ever be blended out in the pressure tank, but bottling is then always forced to fill them completely.“
Furthermore, the project enabled the sugar and base material handling to be revised. At peak times in the summer, the supplier sometimes had to schedule daily deliveries. Keeping an adequate supply of fresh base material was becoming a problem due to the lack of refrigeration and storage facilities. The existing mixing system did not allow direct batch tracing and had to be transferred laboriously via list export. Operation was only possible via remote access to the system and thus also the transfer of the production recipes, which cost additional time and was also susceptible to operating errors, such as the provision of the wrong flavor for one of the shandy products.
Highest standards of quality and technology – no compromises
Once the problem had been worked out and discussed, the team at Kulmbacher Brauerei took the time to present it to potential manufacturers in the industry. Within the bidding phase, several new ideas already emerged to make the process as efficient and simple as possible at the same time. In addition to the requirement to mix all products directly in-line onto the various filling machines, in this case the ease of operation and integration into the existing process control system was a challenge. The buffer volume for feeding up to three filling lines at the same time had to be as small as possible, but nevertheless cleverly balance out the flow fluctuations that occur. Technical decisions for or against a supplier have always been no purely price-related decisions, but primarily depend on the best concept. corosys beverage technology was selected as the process technology partner and commissioned with the construction of the blending plant and the process integration.
The scope of the project included the integration of the 400 hl outdoor tank for sugar syrup, its equipment for receiving and dispensing the syrup, and the transfer to the blending plant. The blending plant itself consists of the rack for the tanks of basic material and flavoring, below which the high-precision dosing pumps are placed. This is followed by the in-line carbonation system and the buffer tank for minimizing start-up losses and for buffering in the direction of the filling systems. To supply the plant with the various base beers and the finished products, the valve manifold in the area of the pressure tank cellar had to be extended accordingly and integrated on the part of the control system. The description of the process as well as its programming and commissioning in the Braumat system were part of the scope of supply.
The process itself is designed as follows for the Radler products: Beer or non-alcoholic beer is selected and requested by the brewer in the control room in the filter cellar in the pressure tank cellar by recipe pre-selection and release. The basic ingredients and flavors must be released by the logistics department by code release after they have been placed on the rack – this prevents incorrect production with, for example, mixed-up flavors. Once all ingredients are compatible with the selected recipe, the process step to vent the buffer tank and product lines towards the filler begins. In the process, a drinkable lemonade is first created within the blender, which is then blended with the beer to form the beer-mixed beverage with high precision. After the request and release of the filler control, the system starts in-line production of the product and first advances product into the buffer tank by volume and high-precision density-sonic measurement. At the same time, the oxygen level must be below 100 ppb. Instead of a large buffer tank volume, an optimum control concept is used, which additionally minimizes the fluctuations at the start of the process. In addition to lower investment costs, a smaller buffer tank also means lower costs when operating the plant. Especially in the consumption of CO2 or CIP media. The alcohol-free product, too, is adjusted again on the blending plant to create the typical character of Mönchshof beer. This is not done directly at the dealcoholization plant.
All products are adjusted in the carbonation plant to the desired CO2 content in the finished product. Apart from the GDI gas injector, no other installations such as static mixers are required for this. The entire process is monitored in-line with high-precision measuring sensors from Anton Paar. Of course, the necessary sampling points for CTA and microbiological average samples are also installed.
„Since switching from conventional production in the pressure tank to in-line blending, we have been able to eliminate several problems. The retention time of the soda with the beer is very short because the product goes directly to the filler, so there are neither the segregation problems nor the secondary fermentation problem,“ Sack acknowledges. He also says that the filling quantities can be freely selected. „Especially because mixed beer beverages are always filled at the end of the week in our house, the filling shifts can now be fully extended. Also the in-house production of the lemonade component in the in-line mixer, has replaced the transport of the lemonade, which logistically brought a lot of advantages in terms of costs but also quality,“ Sack continues.
In Kulmbach, particular importance was attached to proper process execution. As is often the case, commissioning was hampered by the circumstances of the pandemic. Nevertheless, with the help of remote commissioning during another peak phase of the pandemic in the spring of 2021, it was possible to achieve a significant milestone by means of the prepared programming and to carry out the changeover to the existing system as quickly as possible after the successful software test. The approaching summer season had already started and the connection to the filling lines had worked in time. With the relaxation of the measures, the system was able to start operation quickly after being set up on site in June. Further optimization measures rounded off the process flows and communications with the filler and ERP system interfaces.
„The fully automatic inline mixer was visualized in Braumat and integrated into the pressure tank and filling control system. This is a very sensitive and technologically sensitive point in the brewery that does not forgive any mistakes. We were all the more satisfied that this could be integrated so smoothly, thanks to intensive preparation and simulations,“ says Martin Sack, summarizing the completion of the work on the process technology.
All parts were selected as desired from the catalog of well-known suppliers and designed to fit beforehand, so that stock-keeping for spare parts could be kept simple and, if necessary, exchanged with the existing plant. Thanks to the modular design, an extension with additional metering stations, for example for new product variants with additional components, would be easy to implement.
Conclusion: Don‘t be dazzled by the intrinsically simple process, but consider the conditions
As mentioned at the beginning, the Kulmbacher team is used to „life on the construction site“. Nevertheless, the bar is set high when it comes to technical requirements. Permanent provisional solutions are not accepted. The circumstances and the fact that the plant will already be expanded again in the foreseeable future have presented customers and suppliers with a challenge in the project. Despite delays caused by the pandemic, both partners are more than satisfied with the result. The plant runs at the previously defined capacity of 150 – 350 hl/h simultaneously on up to four filling lines. Quality problems and awkward handling are a thing of the past. With control engineering finesse and process engineering safety, corosys was able to contribute to the success of the project.