A Swabian recipe for success

Pretzel twisting machine with pneumatics

Soft pretzels are one of the most popular breakfast treats in southern Germany. It takes skill, practice and time to achieve the perfect symmetrically twisted shape with a fat belly and thin arms. Or simply a clever automation solution.

The list of ingredients for traditional pretzel dough is quite straightforward: just wheat flour, water, yeast and salt. But twisting the dough demands careful attention. The baker takes a small portion and rolls it by hand on the work surface to form a strand that tapers at each end. Next, the baker lays the strand of dough in a U-shape, lifts the ends with one quick movement, twists them by 180 degrees and lays them down again. Finally, the two ends are pressed onto the U-shape and the typical pretzel form is ready. A skilled baker can produce up to 600 pretzels per hour like this. The process is now easier at the Schill bakery: the dough is put into the pretzel twisting machine, the power button is pressed, and that’s it.

Fat belly and thin arms

The Schill bakery produces around 10,000 pretzels a day for its eleven branches. As well as the high speed of production, the traditional shape is particularly important. Before being dipped in a lye solution and going into the oven, the pretzel dough passes through a compact production line. It is first kneaded, divided into portions and shaped into a strand – all automatically. The strand is then positioned with millimetre precision on the conveyor belt by a positioning unit from Festo, so that the grippers can later grip in exactly the right places and form a symmetrical pretzel. This is followed by the actual twisting process in which gripping technology with actuators from Festo is used. Everything happens at lightning speed: the strand of dough becomes a precisely twisted pretzel in less than a second. Sensitive end-of-arm tools grip the ends of the dough, twist the strand and gently press the ends onto the outside edges. This process produces up to 2,300 pretzels per hour – precisely shaped with pneumatics from Festo. The complex single-strand pretzel braids are made in exactly the same way. Only a few steps are required to switch from one to the other.

Flour dust and sensors

From compressed air preparation to drive and gripping technology: the pretzel twisting machine is packed with Festo expertise. When selecting the automation components, it was important to take into account the large amount of flour dust in the bakery. Special seals have been used to ensure a long service life and very easy maintenance since they prevent flour dust from getting inside the pneumatic components. Modern sensor technology also enables the machine to automatically detect faults and stop automatically if, for example, pretzel dough runs over the belt in single-strand mode.

February 2019