The BUND, the Albstadt-Sigmaringen University of Applied Sciences, the City of Sigmaringen and other interested participants did an excursion to two enterprises working with walnuts and nutcrackers close to Stuttgart. The group visited the fruit growing farm Obstbaubetrieb Stirm (company website here), where also small amounts of walnuts can be cracked and processed to oil. Afterwards, we tested tools and machines for this purposes by the company Obsttechnik Feucht (company website here). Thanks to this excursion, we could learn a lot about practical issues and applications which is highly relevant to evaluate practical feasibility.

Photo Gallery: Walnut cracking and processing to oil.
Photos © AlpBioEco, taken by Gloria Kraus

Photo 1: Walnuts are lifted up to separate single walnuts for cracking.

Photo 2: The picture shows the results of the cracking machine. The settings of the machine can be precisely adapted to the walnuts size. The better the feasibility through calibration of settings, the better the end product with fewer shell pieces and need to sort by hand. The adaptability ensures that any walnut from different batches can be processed.

Photo 3: In the best case, the walnut is cut in two halves because this is the highest quality and reaches high prices on the market for human consumption. Here, the picture shows that the mix of nuts and shells could be improved. This quality has to be sorted before it can be processed for direct human consumption but it can be processed to walnut oil.

Photo 4: This picture shows an oil press which can be used for the walnut oil production. For example, the material from Picture 3 can be used here. With high pressure, the oil is extracted from the raw material.

Photo 5: The residual material is a slightly oily “walnut cake”. This material is mostly used as feed. However, it also has other bioeconomic potentials in food and cosmetics which are investigated in AlpBioEco.

Photo 6: In this picture, Jürgen Feucht explained to us how to use his Feucht Obsttechnik fruit harvesting technologies for walnut processing on a small scale and how a good product can be reached. It is important for AlpBioEco to learn which technologies are already available for small and big scale processing and where difficulties can arise during drying, cracking or pressing of walnuts.