What happens to whisky waste?

From animal feed to cosmetics, it’s not just the spirit that’s evolving. Even how we deal with whisky waste is getting smarter.

For years, the by-products of whisky distillation – pot ale and spent lees – have mostly gone to low-value uses like animal feed, or worse, straight down the drain. 

But a new breakthrough could turn that ‘waste’ into something significantly more valuable. Think cosmetics, pharmaceuticals, food ingredients – not just a free lunch for the local livestock.

This isn’t science fiction. It’s the result of a clever collaboration between the biotech startup Ripcell and the University of Aberdeen, with backing from the Industrial Biotechnology Innovation Centre (IBioIC). And it could completely change how distilleries deal with their waste.

Whisky waste: pot ales and spent lees

Let’s break it down. Whisky distillation produces two main liquid leftovers:

Pot ale – the protein-rich stuff left behind after the first distillation

Spent lees – the liquid from the second distillation, typically just binned

Pot ale is already used in low-cost animal feed by distilleries like The Macallan. But its uses expand beyond that.

William Grant & Sons made headlines when Glenfiddich began converting distillation waste, including pot ale, into low-emission biogas. They even use it to power their delivery fleet. Trucks run on ultra-low carbon fuel produced onsite – reducing carbon emissions by up to 95% compared to diesel. That’s a distillery literally running on whisky fumes.

Arbikie Distillery, already known for its field-to-bottle ethos, uses pot ale as a liquid fertiliser and soil conditioner on its estate farmland. While still in development, Bruichladdich has been actively exploring options for anaerobic digestion using pot ale to produce renewable energy.

From farm fodder to fine chemicals

Unlike pot ales, spent lees hasn’t been much use at all – until now.

Using a process based on liquid chromatography, Ripcell’s new method extracts high-value organic acids, like lactic acid, from these waste streams. Lactic acid isn’t just something your legs complain about after a run – it’s also used in everything from skincare to biodegradable plastics. And the market for it is massive.

According to early estimates, this chemical upcycling process could be worth up to £90 million globally. Which is quite a jump from pig feed.

A sustainable win

It’s not just about money. The process also has a far lower carbon footprint compared to traditional chemical manufacturing. Ripcell’s analysis suggests it could slash global industry emissions by nearly 400 million kg of CO₂e each year. That’s like taking 85,000 cars off the road – and doing it with whisky waste.

Plus, since every distillery’s waste stream is slightly different (thanks to water source, grain, yeast, and process quirks), there’s potential for an entirely new conversation – chemical terroir anyone?

“Around 2.6 billion litres of wastewater are produced from the Scottish whisky industry each year, so the potential of this process is huge”, explains Dr Eve Wildman, founder of Ripcell.

Huge, indeed. And with Chivas Brothers already providing pot ale and spent lees from 25 distilleries, there’s plenty of raw material to work with.

Circular whisky? Yes, please.

“This project is a brilliant example of how we can add economic value by taking a circular approach to co-products and applying biotechnology,” said Dr Liz Fletcher from IBioIC.

She’s spot on. This is the drinks industry thinking smarter, not harder, to find value in places we used to ignore and reduce environmental impact along the way.

Animal feed isn’t going anywhere. But whisky waste turning into skincare? Now that’s a glow-up.

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