Upcycling residual materials from the brewing process

For most breweries, brewer’s grains are just what’s left over after brewing and often merely used as animal feed. In some cases breweries even have to pay for their disposal, but much more is hiding in these residual materials from the brewing process.

A project team pursued jointly by Steinecker and the two development specialists Prof Waldemar Reule and Dr Rainer Gottschalk is now demonstrating how these materials can be managed.

One of the latest Brewnomic modules is a solution for material upcycling of residual materials from the brewing process and using them for energy recovery. The solution is being examined and optimised in a pilot installation as part of a Steinecker development project.

Whereas the Brewnomic has so far focused only on using residual materials for energy recovery, the project team has now developed a process for material recovery. This process consists of three steps:

1. First, proteins are extracted from the residual materials. This is done in a three-vessel system, similar to the concept of the CombiCube brewhouse. Following dispersion and hydrolysis, protein is separated by means of membrane filtration.
2. In the second step, the remaining biomass is acidified. After that mineral fertiliser is obtained by means of an ion exchanger.
3. This is followed by energy recovery in the form of biogas production. The brewery’s wastewater is also added and purified here.

Thanks to the trends towards a sustainable, healthful and vegan lifestyle, demand for plant-based protein sources is rising in the manufacturing industry. Potential buyers of this highly sought-after raw material include not only dairies and food-processing plants, but also producers of food supplements and the cosmetics industry. Moreover, selling the mineral fertiliser and the savings achieved by feeding in biogas also pay off for the brewery. So the sum of annual revenues results in a return on investment (ROI) of just a few years, which is substantially shorter than that of a classical biogas plant where the spent grains are used only for energy recovery.

The Ustersbacher Brauerei in Bavaria will be the first to use the concept developed for spent-grains upcycling in shopfloor reality.

“Over the past 10 years, we’ve already implemented a number of measures. With each of these, we’ve taken one step at a time towards achieving our goal: to become an energy-self-sufficient brewery using the Brewnomic concept. So it is only logical that our aim now is to also make maximally sustainable use of the residual materials from the brewing process,” explained brewery owner and manager Stephanie Schmid.

Image credit: ©stock.adobe.com/au/Anna