Brewing by-products

This is part of our series on upcycling.

Brewer’s spent grain (BSG) is arguably the quintessential food by-product, with much written about its upcycling potential.¹ BSG is rich in protein and fibre, making it nutritious, but the high fibre in particular posing textural challenges that must be worked with when using it as an ingredient.²

For every litre of beer brewed an average of 200g of wet BSG (or 40g dry) is produced.³ In 2020, 36.4 million tonnes of BSG were produced globally.⁴ This is a huge untapped resource, yet several barriers have hindered this latent potential. BSG has a short shelf-life because it is warm, wet and still rich in fermentable sugars, providing the perfect environment for microbial life to flourish, such that, if not immediately prevented through processing or storage, it quickly begins to ferment once it is removed from the fermentation vessel, and spoils quickly. Most breweries don’t have the infrastructure or the space to quickly and safely cool, store, dry and process BSG, and it is usually classified as waste once it leaves the brewery premises, unless strict handling procedures are adhered to.

Today BSG is often used as feed for animals.⁵ This makes sense in some contexts, but in deciding how we use food by-products, we must keep in mind the future of food we want to see flourish. A huge commercial brewery sending its BSG to a factory farm as feed might prevent waste from going to landfill. But in solving one problem, we might be locking in other undesirable qualities of the current food system, like industrial animal agriculture.⁶ We will further explore upcycling tradeoffs like these in a future essay. Upcycling BSG into food that can directly feed people is another, more direct option for making use of this untapped potential that we explore here. And though BSG is the main by-product people associate with brewing, it's not the only one. Residual brewer’s yeast, hot trub and old waste beer are all also by-products of brewing and breweries that might too have potential high-value uses.

Here we present some of our culinary research into ways we can better utilise brewing by-products:

Contributions & acknowledgements

Eliot wrote the article, with contributions and editorial feedback from Josh.

Eliot photographed the BSG in our food lab.

Endnotes

[1] Kieran Lynch, Eric Steffen and Elke Arendt (2016), ‘Brewers' Spent Grain: a Review with an Emphasis on Food and Health’, Journal of the Institute of Brewing; Simon Bolwig, Michael Spjelkavik Mark, Maaike Karlijn Happel and Andreas Brekke, A. (2019). ‘Beyond animal feed?: The valorisation of brewers’ spent grain’, in: From Waste to Value: Valorisation Pathways for Organic Waste Streams in Circular Bioeconomies, Routledge, Abingdon, UK.; Pradeep Puligundla and Chulkyoon Mok (2021), ‘Recent Advances in Biotechnological Valorization of Brewers' Spent Grain’, Food Science and Biotechnology; Andela Zeko-Pivač, Mairn Tišma, Polona Žnidaršič-Plazl, Biljana Kulisic, George Sakellaris, Jian Hao and Mirela Planinić (2022), ‘The Potential of Brewer’s Spent Grain in the Circular Bioeconomy: State of the Art and Future Perspectives’, Frontiers in Bioengineeering and Biotechnology; and many others... 

[2] Andela Zeko-Pivač, Mairn Tišma, Polona Žnidaršič-Plazl, Biljana Kulisic, George Sakellaris, Jian Hao and Mirela Planinić (2022) ‘The Potential of Brewer’s Spent Grain in the Circular Bioeconomy: State of the Art and Future Perspectives’, Frontiers in Bioengineeering and Biotechnology.

[3] Mahesh Gupta, Nissreen Abu-Ghannam and Eimear Gallaghar (2010), ‘Barley for Brewing: Characteristic Changes during Malting, Brewing and Applications of its By-Products’, Comprehensive Reviews in Food Science and Food Safety; Maria Victoria Santos, Natalia Ranalli, Juliana Orjuela-Palacio and Noemi Zaritzky (2024), ‘Brewers spent grain drying: Drying kinetics, moisture sorption isotherms, bioactive compounds stability and Bacillus cereus lethality during thermal treatment’, Journal of Food Engineering. The exact composition and yield of BSG varies between different styles of beers.

[4] Andela Zeko-Pivač, Mairn Tišma, Polona Žnidaršič-Plazl, Biljana Kulisic, George Sakellaris, Jian Hao and Mirela Planinić (2022) ‘The Potential of Brewer’s Spent Grain in the Circular Bioeconomy: State of the Art and Future Perspectives’, Frontiers in Bioengineeering and Biotechnology.

[5] Simon Bolwig, Michael Spjelkavik Mark, Maaike Karlijn Happel and Andreas Brekke (2019), ‘Beyond animal feed?: The valorisation of brewers’ spent grain’, in: From Waste to Value: Valorisation Pathways for Organic Waste Streams in Circular Bioeconomies, Routledge, Abingdon, UK. 

[6] A craft brewery sending its BSG to an agroecological farm as feed for its animals might be a different story.