How Scottish scientists could turn 2.6 billion litres of whisky waste into £90 million of 'liquid gold'

A new method to extract valuable chemicals from whisky waste could transform manufacturing and be worth up to £90 million, scientists have claimed.

Aberdeen start-up Ripcell is working with researchers from the University of Aberdeen to examine the feasibility of recovering high-value compounds, such as lactic acid, from pot ale and spent lees, which are co-products of the first and second stages of the whisky distillation process. Experts say the extracted products have potential applications in sectors such as pharmaceuticals, food and drink, and cosmetics, where manufacturing typically depends on unsustainable, petrochemical-derived ingredients.

The groundbreaking project has been supported with funding from the Industrial Biotechnology Innovation Centre (IBioIC), with samples of waste streams provided by whisky giant Chivas Brothers from 12 of its distilleries.

Pot ale and 'spent lees' are co-products of the first and second stages of the whisky distillation process.

Following the success of the feasibility study, the next phase for the team will involve scaling up the separation process to prove its viability at an industrial scale.

Ripcell founder Eve Wildman said: “Around 2.6 billion litres of wastewater is produced from the whisky industry every year, so the potential of this process is huge. For decades, the majority of these co-products have been used as animal feed, but we have found a new, more valuable option to deal with spent lees that could change the ways in which distilleries manage and process their residues.

“At the same time, this could be transformational for the chemicals industry. By taking a sustainable approach to manufacturing key compounds, rather than using fossil fuels, we can help to reduce greenhouse gas emissions from the production process. For every kilo of bio-chemicals produced, we can remove 1.59kg of harmful greenhouse gas emissions.”

Alan Mccue, senior lecturer at Aberdeen University, said: “The idea of utilising wastewater from a traditional industry like whisky production for the recovery of bio-based chemicals is highly innovative. It’s great to see Scottish heritage being linked to sustainable chemical production. The outcomes of this IBioIC funded project are really exciting.”

The research team developed a process using a separation technique known as liquid chromatography to isolate and extract higher-value acids, initially from pot ale. That system has now been adapted to retrieve additional solvents from the spent lees. While residue from pot ale is typically used in low value applications such as animal feeds, spent lees are currently discarded. Up to ten litres of spent lees are generated for every litre of whisky that is distilled.

A life cycle analysis of the process was also completed to quantify its impact on the environment. Estimates suggest that on a global scale, the new manufacturing method for target chemicals could reduce industry emissions by 392 million kg of CO2 equivalent per year.

Liz Fletcher, director of business engagement at IBioIC, added: “This project is a brilliant example of how we can add economic value by taking a circular approach to co-products and applying biotechnology. For both whisky producers and the chemicals industry, this process marks a significant step forward in reducing the environmental impact of manufacturing. We look forward to supporting Ripcell throughout its next steps to bring the process closer to commercial application.”

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