Optimal operation for chocolate storage tanks


The VEGABAR pressure transmitters installed in Barry Callebaut’s Belgian chocolate factory ensure that operations run smoothly for its chocolate storage tanks.

It is said, “All Belgians are loyal to their chocolate.” This is especially true in Wieze, located about an hour’s drive from Brussels, as it is home to the largest chocolate factory in the world that is run by Barry Callebaut.

This site produces around 350,000 tonnes of fine cocoa products per year, serving as raw material for the food industry and used in an estimated 25 per cent of the chocolate consumers worldwide. In working with customers like Nestlé, Unilever and Mondelez, Barry Callebaut provides the best chocolate recipes for their products.

A look behind the scenes at the Belgian factory gives a good insight into its innovative prowess, founded on tradition and history. 

VEGA recommended the VEGABAR pressure transmitters with extremely resistant ceramic measuring cells.


With over 20,000 bioactive ingredients, cocoa products are considered by many to be a superfood. Like that of wine, the production process for chocolate depends on specialists’ high level of expertise.

As the market differentiates between consumer cocoa and premium cocoa according to origin, location and harvest year, Barry Callebaut designs individual solutions to suit each customer’s requirements.

To be able to provide the required chocolate varieties in the right quantities at any time, they are filled into tanks and stored at a temperature of about 40°C. Each of these double-bottomed tanks holds a volume enough to produce one million chocolates. They are heated with water, while rotating agitators keep the liquid masses in the desired state.

Two VEGABAR pressure transmitters are installed at the upper and lower ends of the tank to form a differential pressure measuring system. They reliably monitor the supply to the production line by providing two level values that are factored together. They transmit the resulting measurement data to the plant’s process control system. Tanks whose levels fall below a certain limit are refilled within a defined time window.

Measuring cell in a yummy environment

For the chocolate tanks, VEGA recommended the VEGABAR pressure transmitters with extremely resistant ceramic measuring cells. Sensors with front-flush metallic diaphragms are usually the first choice for hygienic applications. But in this case, the ceramic CERTEC measuring cell had more to offer – a modular connection concept with a hygienic, front-flush design.

VEGABAR pressure transmitters are certified according to 3A and EHEDG and able to withstand extreme conditions, thanks to their high chemical and temperature resistance. They operate drift-free and without oil.

And they are so robust that even solid, abrasive particles in liquids cannot harm them. Perfect for chocolate, as it is also extremely viscous, sticky and erosive. Thanks to the robust ceramic measuring cell, measurement in the storage tanks remains stable even if solid ingredients are in the mixture. Nuts or cocoa bean shells are therefore not a problem, but rather a kind of “favourite variety.”

Drift-free operation

The installed generation of VEGABAR pressure transmitters has withstood the extreme challenges at Callebaut reliably and virtually drift-free since 1990.

“Sensors with metallic measuring cells are clearly inferior here,” VEGA product manager for pressure instrumentation Natalie Waldecker said, who is responsible for this long-term stable measuring principle.

Drift is a phenomenon that slowly creeps into pressure measuring systems. This has to be taken into account when using transducers with metallic measuring cells. The so-called “long-term drift” is one of the “normal” signs of fatigue as a measuring cell ages. The more often a thin metal diaphragm is subjected to a load, the less precisely it will return to the specified zero point. For the operator, this means additional work in compensating for drift by recalibrating the instrument.

But ceramic CERTEC measuring cells operate practically drift-free. The hardness and limited but precise flexibility and range of motion of the ceramic material means that they exhibit virtually no material fatigue or drift. Self-calibrating ceramic cells therefore significantly extend the time between necessary recalibrations.

Using VEGABAR differential pressure measurement, Barry Callebaut can ensure constant filling of the containers.

Chocolate trends  

The Wieze chocolate maker sees itself more as a laboratory of the future than a factory, because nothing is as fast-moving as trends in the food industry. Just three to four decades ago, children grew up having to choose between two types of chocolate – light or dark. Today, countless varieties fill entire rows of shelves in supermarkets. There is little that doesn’t already exist, or will not exist tomorrow, with trends ranging from low-sugar to dairy-free.

That’s why the creative minds at Barry Callebaut are now tinkering with oat milk, coconut blossom sugar and microbiotic muesli flakes, among other things.


Over the years, the brown storage tanks have held many diverse mixtures, states of aggregation and textures. The deployed electronic pressure measurement technology contributes to reliable management as well as precise and efficient control and regulation of the production processes.

In principle, all VEGABAR pressure transmitters are suitable for this measuring principle, as they can be combined with a second sensor to form an electronic differential pressure system. Compared to a conventional measuring solution, installation is much simpler, as it doesn’t require thermal insulation. At the same time, the combined measuring system is much more accurate.

Driving force for innovation

No matter what the quality of the end product, the Barry Callebaut philosophy requires the same uncompromising care for all production lines – from the raw materials used to the measurement technology.

With the help of VEGABAR differential pressure measurement, Barry Callebaut can run automated processes and ensure constant filling of the containers. This ensures uninterrupted production and reliably avoids costly process interruptions, allowing the chocolate experts to focus more on product innovation for its customers. For them, it’s about creating new taste experiences using new ingredients – like a vegan, low-sugar Magnum variety using Barry Callebaut chocolate.

To discover more about the VEGABAR pressure transmitters, visit www.vega.com/en-au/products/product-catalog/pressure.

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