It all starts with the mash: the mixture of malt and water, which is stirred and gently heated for several hours. The resulting liquid is known as the wort, and eventually, several processing steps later, as beer. The remaining malt - known as brewer’s spent grain - has a much less glamorous path ahead of it. It usually ends up as animal feed or on the compost heap.
Researchers from Empa’s Cellulose and Wood Materials laboratory, led by Gustav Nyström, are looking for ways to valorize this residue. They have developed a process to produce high-quality nanocellulose from brewery waste - a versatile biodegradable raw material that can be processed, for example, into packaging materials or fiber-reinforced polymers. The researchers published their findings in the journal ACS Sustainable Chemistry & Engineering.
To explore the potential of nanocellulose from brewer’s spent grain in greater detail, the researchers varied the individual pretreatment and processing steps in order to test their effects on the final product. For example, the quality of the nanocellulose fibers was improved by bleaching and oxidation of the starting material. Different freezing processes can be used to control the size and orientation of the pores in the aerogel, which in turn influences its insulating and mechanical properties.
Grain instead of wood
