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World’s largest underground cheese store
Drilling holes with Betek for famous Swiss cheese

To prevent any misunderstanding right from the off: we’re not talking here about the famous holes in the cheese, but rather the huge holes being driven into the sandstone in order to create more space for the famous Kaltbach cheese from Emmi in Switzerland to rest and mature.

For months already, work has been going on boring an extensive gallery system, which connects to the centuries-old labyrinth of underground caves, within the Santenberg, an elongated sandstone hill in the northwest of Sursee, in the Canton of Lucerne. All in all, a total of around 50,000m3 of sandstone is being excavated from the Santenberg.

The excavation work is being done by long-established tunnel construction specialists Rothpletz, Lienhard + Cie AG. They are using a 63-ton Eickhoff ET 250Q road header and putting complete faith in quality tools from the Black Forest. Working in tandem with Betek’s customer support team, Swiss Betek partner BAZ Service AG from Horgen proposed a combination of two tried and tested bits for the job. The road header’s cross-cutting head is thus fitted with a mix of Betek B47GK19/70E and B47GK17.5LK75/E round shank cutter bits. This enables the machine’s operators to master the greatly changing sandstone strata, which have differing levels of compression and a high quartz content, making cutting away the rock a more difficult task. The excavation cross-sections vary from 25.5m2 to 32m2. The storage galleries are being cut out to a width of 4.8m and a height of 5.7m. The dust separation scheme used for the excavation work is remarkable. The driver’s cabin was completely sealed for the job and gets provided with filtered fresh air. The extraction vent behind the machine is spread over four airduct lines and built directly onto the arm. The dust thus gets sucked up directly behind the cutting head – and adherence to the prescribed limits is thus also assured.

A good climate for maturing cheese

The new gallery system inside the Santenberg lies within the solid sandstone formations of the upper marine molasses, which formed around 16 to 22 million years ago. The sandstone is ideally suited for maturing cheese, as it regulates the humidity. The climate in the cave is stable all year round with an air humidity level of 94% and temperature of ten to at most 12.5°C. The cheese matures naturally in the cave, i.e. without any artificial climate control. In other words, any sealing of the surface of the rock in the cheese maturing storage galleries with sprayed concrete is not wanted. The rock, which in the actual gallery areas is fortunately practically free of any cracks or open seams, is left bare and fixed with individual GRP rock anchors.

Cheese aficionados appreciate this, because fine cheese behaves like choice wine. Only through careful storage under precisely controlled conditions does it become a complete delight. Kaltbach Emmental AOC cheese from Emmi is, however, recognisable not only for its unique taste, but also for its appearance. The blackish brown patina is the natural product of long, careful maturing in the mineralised air of the Emmi sandstone cave. The thinner the rind, the better the cheese. This is a detail to which the Emmi cheese masters devote many, many hours.