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Brewing beer -

Unless you make your own beer, you may not have given much thought to the waste products generated during the brewing process.

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Priorities -

Indeed, most people are more concerned with enjoying their frosty beverage than they are with the efficiency of the process that makes it available to them.

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Main by-product -

It may surprise you to learn, then, that one of the key by-products of brewing beer is a load of wet, sticky shavings referred to as spent grain, or beer sludge.

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Statistics -

Globally, brewers produce around 37 million tons of spent grain per year, and roughly 20% of that amount ends up in landfill.

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Useful chemicals -

Given that beer sludge contains several useful chemicals, however, researchers are now beginning to look at whether it can be put to better use.

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Cattle feed -

Historically, around 70% of beer sludge has been repurposed as cattle feed.

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Biogas -

An additional 10% is used for making biogas. In the race to find a sustainable alternative to fossil fuels, this is also a positive use for the product.

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Landfill -

Some 20% of brewers’ spent grain, however, ends up in landfill, and there are two main reasons that researchers and companies are looking to change this.

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Greenhouse gas emissions -

Beer sludge ending up in landfill is bad for the environment, because it releases methane into the atmosphere as it decomposes.

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Avoidable cost -

Brewers also have to pay to send their spent grain to the disposal facility–a cost on the balance sheet they would rather avoid.

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The search for alternative uses -

So, what exactly are researchers looking at in terms of alternative uses for spent grain? The first promising option is food and drink.

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Upgrain processing system -

In 2024, the Swiss start-up Upgrain launched a processing system that is able to turn brewers’ spent grain into protein and fiber.

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Approved by authorities -

The protein and fiber that the system produces has been approved for human consumption by both the US Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA).

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Already on the market -

Upgrain has already started selling protein and fiber extract from spent grain to food manufacturers that make products such as pizzas, granola, and chips.

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Plant-based meat alternatives -

It is also being used in plant-based meat alternatives, such as those launched last year by the Swiss supermarket chain Migros.

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Vegan milk -

Certain large brewers, such as Chicago-based Molson Coors, have even started to make vegan barley milk using the protein from their spent grain.

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Coors' vegan milk -

According to Molson Coors, its vegan milk product, Golden Wing, has a "rich and creamy" taste and has 25% less sugar than most oat milks.

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Added benefit -

In addition to reducing waste, using beer sludge to make plant-based protein at scale would help free up land.

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Freeing up land -

It could free up the small areas of arable farmland that are used to grow wheat, soy, and pea for edible vegetarian protein.

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Bigger scale -

And if beer sludge were used to replace meat, it would free up far larger areas of land that are used for cattle farming all over the world.

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Challenges -

Using spent grain in food products is not without its challenges, however. Firstly, it can be difficult to convince people to buy the products.

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Hard sell -

Indeed, it is easy to understand why people might feel uncomfortable about buying and consuming food that is described as upcycled.

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Rebranding -

However, the solution to this could be as simple as reframing spent grain as an ingredient, rather than a waste product.

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Longevity -

Another challenge is related to the fact that spent grain contains a lot of moisture and therefore spoils quickly.

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Short time window -

In order to avoid mold and microbial infection, manufacturers therefore must use the beer sludge close to where it is produced.

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Potential for preservation -

As it currently stands, this is not always practical. In order to resolve this, scientists are looking at ways to facilitate preservation.

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Other uses -

In terms of non-edible uses for spent grain, one option that is receiving a lot of attention is leather production.

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Leather production - Indeed, London-based company Arda Biomaterials has successfully used supramolecular chemistry to make proteins from spent grain that mimic the proteins in animal leather.

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Arda Biomaterials -

According to Arda’s founder, Brett Cotten, the company’s offering is more sustainable than other leather alternatives.

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Environmentally-friendly -

Indeed, its first test material was made in a home lab, using only standard kitchen equipment and brewers’ spent grain.

Sources: (BBC) (ScienceDirect)

See also: How Japan is recycling food waste back into food

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