KARZ: A Building Material Made from Coffee Grounds

Every day, billions of cups of coffee generate vast amounts of coffee grounds as waste. Instead of ending up in landfills, this by-product can be transformed into something valuable. Our partner K-MÄLEON has taken up this challenge and developed KARZ, an innovative insulating material made from recycled coffee grounds.

The idea came from Olaf Elze, the director of the German company K-MÄLEON. KARZ combines dried coffee residues with a natural foaming agent to create a porous, lightweight material with strong thermal insulation performance. The process occurs at room temperature, making it a low-energy and environmentally friendly method. As at least half of the material is organic coffee waste, KARZ actively contributes to circularity and reduces the overall carbon footprint.

For the GreeNest project, KARZ represents one of the Standardised Packages we are developing together with our partners — practical, scalable solutions that can be applied in real construction projects. By demonstrating how waste can be transformed into valuable building products, KARZ shows the potential of innovation to make the construction sector more sustainable.

If you want to know more details on the development process, technical properties, and future applications of KARZ, read the full press release.