Brewer’s Spent Grains—Valuable Beer Industry By-Product

The brewing sector is a significant part of the global food industry. Breweries produce large quantities of wastes, including wastewater and brewer’s spent grains. Currently, upcycling of food industry by-products is one of the principles of the circular economy. The aim of this review is to present possible ways to utilize common solid by-product from the brewing sector. Brewer’s spent grains (BSG) is a good material for sorption and processing into activated carbon. Another way to utilize spent grains is to use them as a fuel in raw form, after hydrothermal carbonization or as a feedstock for anaerobic digestion. The mentioned by-products may also be utilized in animal and human nutrition. Moreover, BSG is a waste rich in various substances that may be extracted for further utilization. It is likely that, in upcoming years, brewer’s spent grains will not be considered as a by-product, but as a desirable raw material for various branches of industry.