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Flow rate measurement of problematic media

Precise dosing of hop extract – Cooperation with OeTTINGER GETRÄNKE

Durchflussmesser FLOWave in einer Anlage von OeTTINGER GETRÄNKE

When it comes to many of the processes in the pharmaceutical and biotechnology sectors, as well as in the food and beverage sector, measuring the flow, temperature, or concentration of various media is crucial for maintaining consistent product quality. Flowmeters that operate using the patented SAW process offer valuable options: as well as measuring flow and concentration, they provide additional measured values such as media temperature, they detect contaminants, and are maintenance-free, which can significantly reduce operating costs. They also function reliably even with very viscous, syrupy, or pasty media. One such example is hop extract, which large breweries, in particular, like OeTTINGER GETRÄNKE, use in their beer production.

Did you know?

- OeTTINGER GETRÄNKE was founded in 1731 and has been operating as a family business ever since

- Every year, OeTTINGER GETRÄNKE fills around two billion bottles and cans with beer, beer mixes and innovative soft drinks

- OeTTINGER GETRÄNKE produces regionally and sustainably at its three sites in Oettingen, Mönchengladbach and Braunschweig, with around 800 employees throughout Germany



Precise hop-extract measurement for a reliably consistent beer taste

The amount of hop extract added to the brew determines how many bitterness units a beer will have. Although the IBU (International Bitterness Unit) does not necessarily correspond to the actual perceived bitterness of a beer — since this is influenced by many other substances besides — it has to meet a specific value according to the type of beer in question. This is why the hop extract has to be dosed in as precise quantities as possible during the brewing process. However, one of the commonly used methods, which determines the amount of hop extract by means of the volume of the dosing pump and the number of strokes, is prone to errors. The pump acts more like a “guesstimating tool”, as it counts the strokes even when it is running empty, which can happen occasionally. It is only usually when the finished product is analysed that the deviation from the required bitterness units is noticed. This then involves time and effort to improve the beer retrospectively. The batch is held back, and new beer with compensating bitterness units has to be brewed, which is then blended with the “old” beer. The documentation must then be updated, which creates additional work. It therefore makes sense to find alternative measurement methods, but these are not easy to come by. For example, magnetic-inductive sensors are ruled out from the start because hop extract is not electrically conductive, while flowmeters with impellers are unsuitable due to the high viscosity of the medium. This leaves flowmeters that use the Coriolis principle. But these are expensive, and are usually very heavy and with a correspondingly high energy consumption.

Weighing up modernisation versus retrofitting alternatives

To offer breweries a practical alternative for modernising or upgrading, Bürkert worked in collaboration with OeTTINGER GETRÄNKE at their Braunschweig location to carry out a feasibility study. The fluidics experts suggested installing a SAW flowmeter to dose and measure hop extract before it enters the brew kettle, and testing it extensively in operation. There was actually no technical imperative to do so, as the beverage manufacturer was satisfied with his existing dosing solution. However, he is fundamentally interested in new technical possibilities, and the system was not complicated to install or start up. Nor did the service team at OeTTINGER GETRÄNKE need any assistance with this.


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“We are always interested in new technological possibilities, as it’s only by using modern automated technology that we can guarantee excellent product quality while keeping an eye on the economic aspects. Besides, we have a long history of working with Bürkert, and we were curious to see how the test results would turn out.”

Philipp Zoch, Brewmaster at OeTTINGER GETRÄNKE, Braunschweig site

Hygienic flow measurement

The FLOWave flowmeter operates according to the patented SAW (Surface Acoustic Waves) process. The main advantage of this method is that there are no installed parts or constrictions inside the measurement tube, and thus no dead spaces. In addition, measurements are taken without any contact between any of the sensor parts and the medium. This means that the fluid does not affect the sensor parts in any way. The measurement tube behaves just like a straight pipeline, which means that nothing can get trapped. The nominal diameter of the FLOWave is matched to that of the application pipework (DN 15). The compact flow meter, made entirely of stainless steel, measures volume flow with an accuracy of +/-0.4% of the measured value. At the same time, the temperature measurements are accurate to within < 1 °C. The flowmeter data can then be used for documentation and quality control purposes.

Feasibility study successfully completed

The three-year test phase has now been completed, and the FLOWave has stood the test of time in practical use for dosing and measuring hop extract. Philipp Zoch puts it in a nutshell: “To any beverage manufacturer looking to modernize their hop extract dosing and needing to document the quantities supplied to the brew, Bürkert's SAW sensor comes highly recommended.” Another very useful feature of the sensor comes into play during hop extract cleaning: it is able to detect media changes swiftly and accurately, distinguishing precisely between product, cleaning solution, and their mixed phases. This capability enhances the efficiency of the cleaning process.

The many and varied applications of FLOWave

The wear-free, continuous concentration measurement based on the SAW principle also offers enticing opportunities for many other industries. The straight measuring tube is ideal for applications with stringent hygiene requirements, such as in the pharmaceutical, food, or cosmetics industries. The devices are supplied with either a digital interface (via M12 connector) or, alternatively, an analogue 4–20 mA interface. Variants with on-site digital data display are available, as well as a FLOWave L version with ATEX approval for use in potentially explosive areas, e.g. when measuring alcohol or volatile oils. The flowmeter is available for large nominal diameters up to DN 80 and weighs only 6 kg compared to comparable sensors that can weigh up to 240 kg. Even small nominal diameters up to DN 8 are available as standard variants, for instance in pharmaceutical and cosmetic applications. Installation, removal and recalibration can easily be carried out by one person.


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“Any brewery wishing to modernise its hop extract dosing and to document how much hop extract is added to the brew can’t go wrong with the SAW sensor from Bürkert.”

Philipp Zoch, Brewmaster at OeTTINGER GETRÄNKE, Braunschweig site
Reliable fluid technology for modern brewing systems – from the smallest to large breweriesReliable fluid technology for modern brewing systems – from the smallest to large breweries

From the up-and-coming craft beer brewery to the large industrial brewery: The automation and digitisation of brewing processes are the decisive parameters for competitiveness and future viability. With an experienced and far-sighted partner for digital control and measurement technology, you can also set yourself up for Brewery 4.0.