Scientists and industry are finding unusual new uses for brewers' spent grain – the beer industry's largest waste product.

Ponder the idea of a beer well-brewed and enthusiastic drinkers at least are likely to imagine a pint glass filled to the brim with golden nectar.

What they probably won't picture is the mountains of wet sticky shavings that pile up as the largest waste material of brewing beer.

This is what's known as brewers' spent grain, and there is an awful lot of it. Around 200g (7oz) is produced for every litre of beer brewed. Globally some 37 million tonnes is produced each year – equivalent to the weight of around 340 double-decker buses per hour. And as we drink more beer – sales are expected to rise by a third in the next seven years – only more and more will be churned out.

Most brewers' spent grain, around 70% of it, is currently repurposed as cattle feed, while 10% is used to make biogas. Around a fifth is simply sent straight to landfill – at an additional cost to breweries – where it rots and releases methane into the atmosphere.

But inside this beer by-product there are a mountain of useful chemicals to tap, including lots of protein. Researchers and companies are now beginning to explore how these could be put to better use.

Swiss start-up Upgrain is one of these. In 2024, it launched a processing system to turn brewers' spent grain into protein and fibre, passed as fit for human consumption by the Food and Drug Administration in the US and the European Food Safety Authority (brewers' spent grain is, after all, still just grain). The system comes ready for installation on brewery premises: shipping container-sized for micro-breweries and a much larger unit for the likes of Brauerei Locher, Switzerland's second biggest brewer, which opened in September 2024 and is now building Europe's largest onsite facility.

William Beiskjaer, Upgrain's co-founder, argues brewers spent grain is a "kind of hidden treasure in terms of sustainable and healthy nutrition". He says it could help to tackle rising global demand for protein. "There's more and more demand for our foods to be enhanced, especially to get more protein and fibre in our diets," he says.

Upgrain and other producers such as Agrain in Denmark and BiaSol in Ireland are already selling brewers' spent grain protein and fibre extract to food manufacturers for inclusion in baked goods, pizzas, granola and even crisps. It's also being used in plant-based meat alternatives, such as those launched last year by the Swiss supermarket chain Migros, and in a coffee created by Singapore-based company Prefer.

Hype Metre

Brewers' spent grain is a rich source of nutrients which is arguably wasted as cattle feed and produces methane when it ends up in landfill. A host of start-ups are now using it to make everything from vegan barley milk and leather to........

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