Whereas spent grains were previously regarded as a waste product, resourceful breweries are now using them to make pizza or cookies. More of the valuable materials produced during the brewing process are used and waste is avoided. To turn by-products into main products, completely new strategies are needed for circular food production - to protect our planet.
Hardly anyone thinks about the residues of brewing malt, known as spent grains, when enjoying an after-work beer with friends. Despite its valuable components, this by-product of beer brewing has so far only been used to produce biogas or animal feed at best. However, upcycling is increasingly taking place. In order to make use of the nutritionally valuable components contained in spent grains, such as fiber, proteins and minerals, they are also used to make bread, pasta, cookies and bars.
From the former waste product ...
Until now, the processing of these so-called side streams into food was often considered uninteresting. The reasons: too energy-intensive and costly. This is because these by-products often have to be thermally preserved or otherwise treated before they can be further processed into food.
... to valuable food
As with brewers' grains, completely new strategies are therefore needed to turn supposedly inferior by-products directly into valuable main products so that humanity can be fed and the environment protected. Effective, regenerating and self-sustaining circulation systems are needed.
Nature provides models for this: In a living biological system, there is a continuous exchange of substances that enables growth, stress, decay or regeneration, adaptation and development. A circular exchange of substances makes it possible to regenerate molecules and components, which allows the entire system to be maintained. A characteristic of regenerative systems is that they embed themselves as subsystems in other systems.
Nature as a role model
This can be illustrated particularly well using the "forest" ecosystem: Trees absorb carbon dioxide from the air and release oxygen, while at the same time extracting water and nutrients from the soil. The process of photosynthesis enables trees to grow, regenerate, adapt and develop. The oxygen produced during photosynthesis allows other living things to exist. The leaves and branches that die and fall provide the soil with organic material that serves as a food source for microorganisms and insects. These organisms in turn decompose the organic matter and release nutrients into the soil, which can be absorbed by the trees and other plants. Ultimately, there is a circular exchange of substances between the trees, the soil, the microorganisms and the air, which enables the entire ecosystem to be maintained. The "forest" ecosystem is in turn a subsystem of the earth's larger biosphere system.
Circular and suitable for grandchildren
Regenerative food production should function in the same way as these biological systems: It starts with the sustainable agricultural primary production of raw materials. Processing and value creation from all streams is carried out with a focus on direct utilization for human nutrition, on preventing food waste and on reducing the consumption of energy and other resources - which should of course come from renewable sources. The business models should be long-term oriented, circular and therefore suitable for grandchildren.
In concrete terms, this could look like this: Regenerative processes in agriculture actively promote the microbiome in the soil through various outdoor cultivation measures such as crop rotation on production areas. Soil life, in turn, is crucial for increasing healthy yields and biodiversity.
Cell cultures against malproduction
Also conceivable here would be cell cultureswhich could be used specifically for the production of food. The cells for propagation are obtained from the original tissue of the plants - for example the cocoa bean - and transferred to a stock culture without genetic modification. The cultures are then propagated in a special tank in which the environmental conditions can be influenced: Temperature, gas balance, mechanical movement, light and other factors can be closely monitored and controlled in this system. The nutrient sources for these cultures come from local agriculture. The production process is much easier to control than in systems where the use of pesticides and fertilizers is the rule and weather influences are unpredictable.
In this way, more of the goodness from the plant can be provided for human nutrition, while reducing the consumption of resources. Misproduction, associated with food waste, and side streams remain the exception - all streams become main streams. In addition, the cells could be cultivated close to the place of refinement.
Rivals become partners
Ultimately, regenerative food production also requires new business models and collaborations. Former rivals could become partners at a joint production site. One of the business partners would then, for example, process the liquid main stream into plant-based drinks and the other business partner would process the solid main stream into plant-based meat alternatives or baked goods and pasta.
The brewery pizza with healthy ingredients from spent grains is then available for an after-work beer with friends. Regenerative food production also stands for enjoyment with a clear conscience.
About the writers
Thinking and writing the unexpected is Gisela and Tilo Hühn's motto. Acting responsibly together, reflecting and making a difference are the cornerstones of their life concept. The two work as researchers and lecturers at the ZHAW: Gisela Hühn in the research group for food process development, Tilo Hühn as head of the Center for Food Composition and Process Design. Whether at the university or at the kitchen table, both enjoy discussing and working - in pairs or with others - on future food systems and on the question of how to get more of the goodness out of agricultural products during processing.
