From Distillery Floor to Skin Care Shelf: How Scotch Whisky Waste Is Reinventing the Cosmetics Supply Chain
Every year, Scotland's whisky industry generates millions of liters of spent liquid and spent grain — the inevitable byproduct of distilling one of the world's most celebrated spirits. For most of its history, that waste has been a logistical headache: an acidic, yeasty liquid called pot ale, copper-tinged and rich in organic compounds, along with spent barley kernels called draff, their fermentable sugars long exhausted. Disposing of or finding low-value uses for these streams has cost the industry money and contributed to its environmental footprint. Now, two companies — a Scottish green-tech biorefinery and one of Germany's largest specialty chemical manufacturers — have worked out a way to redirect that waste into something entirely unexpected: a premium cosmetic emollient destined for lotions, sunscreens, and color cosmetics sold on American shelves.
Scottish green-tech company Celtic Renewables has partnered with Evonik to produce sustainable ingredients for cosmetics formulations made from by-products of the Scotch whisky industry. The resulting product, ECOHANCE® Soft BOL, is a sustainable emollient boasting a silky, luxurious skin feel. It's a collaboration that sounds almost too clever to be real — turning distillery dregs into something that ends up on someone's face — but it represents a genuine convergence of industrial biotechnology, green chemistry, and a global cosmetics sector under growing pressure to clean up its act.
The Problem Nobody at the Distillery Wanted to Talk About
Understanding why this deal matters requires a brief detour into what actually happens inside a Scotch whisky distillery. The production process, for all its romanticism, is extraordinarily resource-intensive. Barley is malted, mashed, and fermented, which produces a beer-like liquid called wash. That wash is distilled in copper pot stills, which drives off the alcohol and leaves behind enormous quantities of pot ale — the hot, liquid residue at the bottom of the still. Separately, the spent barley kernels, called draff, pile up after the mash has given up its sugars.
Draff consists of the sugar-rich barley kernels that aid the fermentation process, while pot ale is the yeasty liquid heated during distillation. Neither has an obvious high-value application once the whisky is made. Some draff gets dried and sold as animal feed; some pot ale is processed into a nutrient supplement. But the volumes are staggering relative to what the industry can profitably absorb, and both streams carry a significant environmental burden if mishandled.
The Scotch whisky industry has long been aware of the problem. The Scotch Whisky Association and the Scottish Government have supported initiatives aligned with both national biofuel and carbon reduction targets. That institutional backing helped create the conditions for Celtic Renewables to exist at all — and to operate at a scale where a partnership with a chemical giant like Evonik becomes commercially viable.
Celtic Renewables: A University Lab Bet That Paid Off
Celtic Renewables did not emerge from a corporate R&D department. It is a spin-out company from Edinburgh Napier University, whose roots began from a university research project to explore what raw materials and sustainable by-products might be able to replace fossil carbon with biogenic carbon and be converted into high-value, low-carbon compounds. The intellectual architect of the technology was Professor Martin Tangney. Celtic Renewables developed when Tangney opened the Biofuel Research Centre at Edinburgh Napier University in 2007, and after filing patents for the centre's work, Celtic Renewables was formally established in 2012.
The science Tangney's team built upon is not new — it's actually more than a century old. The acetone-butanol-ethanol (ABE) fermentation process was famously used during World War I to produce acetone for cordite manufacturing. But the classic ABE process used grain crops as feedstock, which pitted it directly against food production and made its economics unworkable in a modern, food-secure world. Tangney and his colleagues essentially reinvented the process for the production of acetone, butanol, and ethanol, since traditional ABE fermentation used crop-based feedstocks that often competed with food, whereas Celtic Renewables creates green chemicals from by-products and waste, including reject potatoes that are neither fit for human nor animal consumption and whisky by-products.
The Edinburgh Napier scientists discovered, by collaborating with Scotland's whisky production industry, that the by-product residues from whisky distilling could be combined and used as a new starting material for the process. That insight — that pot ale and draff together could feed the ABE fermentation reactor just as well as virgin grain — unlocked the economics. The feedstock is not just cheap; in many cases, the distilleries are motivated to see it taken away. The research was successful and ultimately gave rise to two international patents for the low-carbon technology.
As the company has grown over the years, Celtic Renewables' innovation has received many accolades, including being named the most innovative biotech SME in Europe at the EU Parliament in 2015, and its founder received an OBE for his services to engineering and energy in 2018. Those aren't just vanity awards. They signal that the technology cleared serious peer scrutiny at a time when many bio-based chemical ventures were still failing to bridge the gap between laboratory promise and commercial reality.
The Grangemouth Biorefinery: Where Whisky Becomes Chemistry
The operational heart of Celtic Renewables is its biorefinery at Grangemouth, a Scottish industrial town on the Firth of Forth that has historically been synonymous with oil refining. There is something deliberately pointed about the choice of location. Celtic Renewables' flagship, state-of-the-art commercial processing plant in Grangemouth is Scotland's first biorefinery using patented and proven technology.
The facility uses ABE fermentation to produce bio-acetone, bio-butanol, and bio-ethanol from locally sourced waste and by-products including pot ale from whisky distillation and rejected potatoes. The process itself mirrors what Tangney's lab proved out at Napier, just at industrial scale. The process starts by mixing draff and pot ale into a slurry that is then fermented into a broth, which creates byproduct gases such as hydrogen and CO2. The broth is distilled to produce butanol, acetone, and ethanol, while the leftover solids are separated, dried, and treated to produce high-grade animal feed. Nothing is wasted twice.
According to the company, these green chemicals generate up to a 65 percent carbon saving in comparison to petrochemicals, and for every tonne of bioacetone or biobutanol produced, almost three tonnes of fossil carbon is avoided. That figure matters enormously for downstream customers like Evonik who need to demonstrate Scope 3 emission reductions across their supply chains — an increasingly non-negotiable demand from both brand partners and regulators.
Celtic Renewables is using fresh investment to fund the planning and development of a new £120 million industrial-scale biorefinery at Grangemouth with ten times the production capacity of the company's current facility. The ambition is explicit: the company is looking to scale up in Scotland and potentially Ireland first, then think globally, working on four next-stage, larger projects involving infrastructure development and operation.
ECOHANCE® Soft BOL: The Product That Ties It Together
The collaboration sees Evonik use Celtic Renewables' innovative bio-butanol — produced from locally sourced waste materials including whisky pot ale and rejected potatoes at its Scottish biorefinery — to manufacture ECOHANCE® Soft BOL, a sustainable emollient designed for cosmetics and personal care products. To understand why this matters, it helps to understand what emollients actually do and why the industry has historically defaulted to silicones.
Emollients are the skin-feel engineers of cosmetic formulation. They determine whether a moisturizer absorbs quickly or sits on the surface, whether a sunscreen leaves a white cast or glides invisibly, whether a foundation feels powdery or satin-smooth. For decades, silicone-derived emollients — cyclopentasiloxane, dimethicone, phenyl trimethicone — have dominated that space because they deliver a distinctive, almost indescribably smooth skin feel that organic oils struggle to replicate. They're also chemically inert, meaning they play well with UV filters and pigments. The problem is that most silicones are derived from fossil feedstocks, and several cyclic silicones have come under regulatory scrutiny in Europe over environmental persistence concerns.
ECOHANCE® Soft BOL delivers silicone-like glide and premium silky sensory, with sensory profiling showing silkiness superior to silicones. That claim — superior to silicones, not merely comparable — is a bold one from Evonik's technical team, and it speaks to the product's core market proposition: this is not a compromise ingredient marketed as "good enough for green formulas." It is positioned as a genuine performance upgrade with sustainability layered on top.
ECOHANCE® Soft BOL has very high pigment wetting capability and is recommended for color cosmetics. The ingredient also shows good UV filter solubility, comparable to isoamyl esters, and helps minimize sticky residue effect in high SPF formulations. For cosmetic chemists, those two capabilities together are genuinely difficult to achieve in a bio-based ester oil. Pigment wetting requires low surface tension and the ability to wet hydrophobic and hydrophilic pigment surfaces uniformly — the same property that makes silicones so effective in color cosmetics. UV filter solubility is critical in modern sunscreens, where high SPF requires loading high concentrations of organic UV filters into the oil phase; a poorly solubilizing emollient will cause filter crystallization and SPF drop-off.
An in vivo Corneometer study reported a +30.3% hydration increase after three weeks with a formulation containing 12% ECOHANCE® Soft BOL. Clinical substantiation at that level gives brand formulators the data they need to make moisturization claims on pack — something that pure silicone emollients, which film rather than hydrate, cannot typically support. A clinical evaluation also concluded that an ECOHANCE® Soft BOL formulation can be considered non-comedogenic. That's a box that needs checking for any ingredient going into facial moisturizers or foundations targeting men who care about skincare but are sensitive to products that clog pores.
The Dual Sustainability Architecture
The product features a unique dual sustainability concept combining responsible sourcing with an eco-friendly production process. It is derived from three types of next-generation feedstocks, all sourced from side or waste streams, and manufactured using a green chemistry process that significantly reduces CO₂ emissions. The two-pronged approach — clean raw material sourcing plus clean manufacturing — is intentional. Either alone would be meaningful; together they represent what Evonik calls a "dual sustainability" architecture that gives brand partners more complete life-cycle credentials to put behind a product claim.
The emollient is produced via Evonik's enzymatic process, which is powered by 100% renewable electricity. Enzymatic esterification, as opposed to traditional acid or base catalysis, runs at lower temperatures, requires fewer processing steps, and generates less waste — advantages that compound on top of the already low-carbon feedstock coming in from Grangemouth. The combination of next-generation feedstocks with low-energy enzymatic esterification results in an exceptionally low product carbon footprint for ECOHANCE® Soft BOL.
The product is also readily biodegradable, meeting OECD 301 F testing standards. For formulators working under EU environmental regulations — or for American brands that sell in European markets — that biodegradability data is increasingly a baseline requirement rather than a differentiator.
The Voices Behind the Deal
The executives at both companies are notably direct about what they see in this collaboration. Wolfgang Goertz, Vice President of Cosmetic Solutions at Evonik, explained the fit in straightforward terms: "The butanol we get from Celtic Renewables fits perfectly with what we need. Our customers really appreciate the cosmetic emollient that we make with this raw material — we are able to achieve great sensory, texture and touch."
That language — sensory, texture, touch — is not accidental. In the cosmetics ingredients business, technical efficacy and consumer-perceivable skin feel are the twin gates that any new raw material must pass. A bio-based emollient that cannot deliver on skin feel will not make it into a premium product no matter how clean its environmental credentials. The fact that Evonik's customers are actively appreciating the finished emollient signals market traction rather than aspirational positioning.
From Celtic Renewables' side, Bettina Brierly, the company's Chief Commercial Officer, put the challenge in sharper terms: "The cosmetics sector faces an immense challenge reducing its Scope 3 emissions." Scope 3 emissions — those embedded in a company's supply chain, upstream and downstream of its own operations — are the hardest category for any manufacturer to control. A cosmetics brand cannot simply swap to renewable electricity at its filling facility and call the problem solved; it needs its ingredient suppliers to operate on cleaner feedstocks. Celtic Renewables bio-butanol, arriving at Evonik's facilities with dramatically lower embedded carbon than petrochemical butanol, directly attacks that Scope 3 problem in a way that internal efficiency measures alone cannot.
Evonik's sustainability goals go beyond carbon reduction. They include transparency and storytelling, from raw material origin to the finished product. That storytelling dimension is real and commercially significant. A brand that can trace its emollient back to a specific fermentation process at a specific biorefinery in Grangemouth, which in turn draws its feedstock from Scotland's whisky distilleries, has something genuinely differentiated to communicate to consumers who are increasingly skeptical of vague sustainability claims.
Why This Partnership Matters Beyond Cosmetics
The Evonik-Celtic Renewables deal is worth examining not just as a cosmetics ingredient story but as a proof-of-concept for a broader industrial model. The Scotch whisky industry produces enormous, consistent, and geographically concentrated volumes of pot ale and draff. Those characteristics make it an ideal feedstock for a biorefinery: predictable volume, reliable composition, and logistical proximity to the processing facility. The whisky industry doesn't need to change what it does; Celtic Renewables simply changes what happens to the waste stream after the distillation is complete.
The company transforms by-products such as whisky pot ale and surplus or rejected potatoes into valuable renewable chemicals, demonstrating how agricultural and food-processing waste can be converted into high-value industrial ingredients through advanced biorefining technologies. The potato angle is worth noting: rejected potatoes — those culled from agricultural processing for being too small, too misshapen, or otherwise unfit for food use — represent another enormous waste stream that has historically been buried, composted, or turned into low-value animal feed. Feeding them into the ABE fermentation reactor alongside pot ale means Celtic Renewables has built a biorefinery that simultaneously solves problems for the whisky industry and for agriculture.
The partnership is expected to strengthen demand for bio-based butanol, sustainable emollients, and renewable specialty chemicals used in cosmetics and personal care formulations, and increased adoption of waste-derived feedstocks could gradually reduce dependence on fossil-based butanol and petrochemical-derived emollients. That substitution effect could be substantial: butanol is used not just in cosmetics but in industrial solvents, coatings, and as a direct fuel additive. Bio-butanol is a four-carbon biomass-derived alcohol with higher energy content, lower vapor pressure, and better water resistance than ethanol, which makes it a more versatile platform molecule than its ethanol cousin.
The Circular Economy in Practice
What Celtic Renewables has built is a working demonstration of what industrial ecologists call a circular economy in practice — not as an abstract goal but as a functioning supply chain. A distillery makes whisky. The distillery's pot ale goes to Grangemouth. The pot ale is fermented into bio-butanol. The bio-butanol goes to Evonik. Evonik converts it into an emollient. The emollient ends up in a sunscreen or a moisturizer on a bathroom shelf. The distillery gets rid of a waste stream it would otherwise have to manage. The biorefinery earns revenue. Evonik gets a more sustainable raw material. Brands get better sustainability credentials. Consumers get a product whose carbon footprint is dramatically lower than the conventional alternative. Every link in that chain is adding value rather than externalizing cost.
As brands seek ingredients that combine functionality with sustainability, waste-derived feedstocks are emerging as a powerful solution — offering both measurable environmental benefits and a compelling connection between raw materials and finished products. That connection — provenance, traceability, and meaning — is increasingly what separates premium cosmetic ingredients from commodities in a market saturated with green claims that often amount to little more than marketing language.
What Comes Next for Both Companies
Building on the success of this collaboration, both companies are now exploring additional applications for Celtic Renewables' bio-based chemicals across a broader portfolio of environmentally responsible cosmetic ingredients. The bio-acetone that Celtic Renewables produces alongside bio-butanol in its ABE process has its own range of industrial applications, and the bio-ethanol stream has potential in personal care as well. The Grangemouth facility, already running around the clock, is just the beginning of what Celtic Renewables has in mind.
Celtic Renewables is planning a new £120 million industrial-scale biorefinery at Grangemouth with ten times the production capacity of the current facility. If that expansion proceeds, the volume of bio-butanol available to Evonik — and to the broader chemicals market — increases dramatically, which is exactly the kind of supply certainty that large cosmetics manufacturers need before they can commit to reformulating a product line around a new ingredient. Scale and consistency of supply have historically been the Achilles heel of bio-based chemical ventures; Celtic Renewables appears to be addressing that constraint deliberately and systematically.
The company argues that switching to bio-based alternatives could cut emissions from everyday cosmetics by up to 60% without changing consumer habits or significantly disrupting manufacturing. That figure is striking precisely because of the caveat attached to it: without changing consumer habits. The promise of sustainability without sacrifice has driven many a failed green product launch. Celtic Renewables and Evonik are betting that they've engineered a product where the sustainability comes from the supply chain rather than from asking consumers to accept a worse experience.
The Whisky Connection as Brand Story
For American consumers — particularly the kind of men who buy premium skincare and have an appreciation for quality spirits — the whisky origin story of ECOHANCE® Soft BOL is not a throwaway marketing line. It's a genuine narrative about upcycling, craftsmanship, and the intelligent use of resources. The same Scotch distilleries producing Speyside single malts and Islay smokers are now, indirectly, contributing to the ingredients in high-end personal care products. That's a story with real texture.
The Edinburgh-headquartered firm has said that the sector is increasingly searching for ingredients that have both functionality and meaning, and waste-derived feedstocks provide storytelling potential for customers. For a cosmetics brand, "storytelling potential" translates directly to marketing differentiation and consumer trust — commodities that are arguably as scarce and valuable as a well-aged single malt.
The whisky industry has spent decades building a culture of terroir, traceability, and craft — concepts that the spirits world borrowed from wine and made its own. Every serious whisky drinker knows the importance of water source, barley variety, still shape, and cask type. The notion that the character of a place — Scotland's climate, its barley fields, its copper-pot distilleries — can be expressed through a product is fundamental to what makes Scotch whisky valuable. That same logic, applied to cosmetic ingredients, becomes a genuine point of differentiation in a market drowning in generic green claims.
From whisky by-products and potatoes to other agricultural waste streams, Celtic Renewables' technology demonstrates how science and circular economy innovation can unlock new possibilities for sustainable cosmetics. The company was not founded to serve the beauty industry — it was founded to replace fossil fuels — but the cosmetics partnership with Evonik represents a high-value destination for bio-butanol that arguably makes more economic and environmental sense than blending it into gasoline at a few percent concentration. When the same molecule can replace silicone in a premium emollient rather than being burned in a car engine, the value extraction from the original waste stream is considerably higher.
What Evonik and Celtic Renewables have put together is a supply chain that runs from a copper pot still in the Scottish Highlands to a moisturizer or SPF product in an American medicine cabinet, with a biorefinery at Grangemouth and a chemical facility in Germany in between. At each step, something that was previously a cost or a burden becomes an asset. That's not a sustainability press release. That's engineering working the way it's supposed to.
