The principle is simple. Butter is placed in the cylindrical upper part and a little salted water in the lower part. If one is then put into the other, the air escapes from the storage container due to the displacement of water. The butter cannot oxidize, remains fresh, is always cooled by water and, unlike most butter stored in the refrigerator, is spreadable. In the upper part, the butter can also be served at the table.

The lower part of the butter dish is stamped out of genuine Westerwald clay in the pottery in Ransbach-Baumbach, and the upper part is cast in molds. Both parts receive a bright green glaze and are fired at 1,250 °C until smooth.

In Ransbach-Baumbach, in the Vorderer Westerwald, where the highest quality clay deposits in Europe are located, is home to the pottery in which these vessels are created. The family business can look back on 150 years of tradition in working with clay - here it is genuine Westerwald clay, sought after for its light coloration and fine plasticity. Densely sintered, fired and glazed, it is non-porous and waterproof, so easy to clean, while impact-resistant and edge-stable.

This product is an example of genuine handicraft; therefore, minor deviations in size and colour may occur.