Brewer's spent grain

Lore & Background

The majority of BSG is composed of barley malt grain husks in combination with parts of the pericarp and seed coat layers of the barley. Its composition can vary depending on the type of barley used, the way it was grown, and other factors, but it is usually rich in cellulose, hemicelluloses, lignin, and protein. BSG is naturally high in fiber, making it of great interest as a food additive, replacing low-fiber ingredients.

BSG has been studied for many uses, including as a food additive, animal feed, fertilizer, paper, ceramics, and mushroom substrate. As a food additive, BSG can be ground and sifted into a powder that increases fiber and protein content while decreasing caloric content, possibly replacing flour in baked goods and other foods. Some breweries that also operate restaurants re-use their BSG in recipes such as pizza crust. An Australian based company, Grainstone, has developed a modular energy efficient process to convert BSG to a premium specialty flour and to produce nutraceuticals including protein isolate, soluble dietary fibre, and antioxidant.

For livestock feed, BSG can be fed wet or dried, and its high protein content offers a wide variety of essential amino acids. Supplementing BSG in cow diets may increase milk yield, milk total solids content, and milk fat yield compared to maize. As a fertilizer, BSG's high protein content translates to high nitrogen availability in soils, and in combination with compost it may improve germination rate and organic matter availability. Studies have shown BSG plus compost has a stronger positive effect on germination than compost alone, and that BSG in soil is more effective at sodic soil reclamation and corn seed germination than gypsum.

Reader's Guide

Brewer's spent grain is significant as a widely available, low-cost byproduct that constitutes the majority of brewing waste, offering multiple pathways to reduce environmental impact. Its high fiber and protein content make it a valuable food additive, capable of increasing nutritional value while reducing calories in baked goods and other foods. The development of processes to convert BSG into specialty flour and nutraceuticals by companies like Grainstone highlights its potential for value-added products. In agriculture, BSG serves as an effective livestock feed that can improve milk production, and as a soil amendment that enhances nitrogen availability and germination, sometimes outperforming traditional amendments like gypsum. Additionally, BSG has been explored in ceramics to affect mechanical strength and porosity, and as a mushroom substrate, where specific ratios with fuel pellets and water have yielded the highest average yields. Its legacy lies in its versatility as a waste material that can be repurposed across food, agriculture, and industrial sectors, contributing to waste reduction and resource efficiency.

Did You Know?

• Brewer's spent grain makes up 85 percent of brewing waste.
• BSG can be used as a food additive to replace flour in baked goods, cookies, and even hot dogs.