Context & Objectives
Noxis, a historic cognac producer in the Charente region, sought to reduce the carbon footprint of its distillation process by 50% by 2030, in line with France’s national low-carbon strategy.
The traditional Charentaise distillation method-using copper cucurbite stills heated by open flame is protected by the Cognac Appellation d’Origine Contrôlée (AOC), which mandates specific materials and techniques to preserve the spirit’s organoleptic profile.
- Regulatory constraints: any modification to the distillation process (e.g. switching to electric or microwave heating) would require AOC approval, as changes risk altering the cognac’s sensory characteristics.
- Technical constraints: Copper’s thermal conductivity and the open flame’s heat profile are integral to the ester formation that define cognac’s aroma and flavour.
Objectives
Astragal has been engaged to:
- Identify low-carbon alternatives to open-flame heating that preserve the organoleptic integrity of the cognac.
- Compare the environmental impact, technical feasibility, and economic viability of the identified low-carbon alternatives.
- Develop a roadmap for AOC modification, including scientific evidence and stakeholder engagement to support regulatory approval.
Our Approach
Various alternative study
Collaborated with INRAE (National Research Institute for Agriculture, Food and Environment) to model the impact of alternative heating methods (induction, electric resistance, biomass, biogas, green hydrogen) on copper heat transfer and volatile compound development. Conducted GC-MS (Gas Chromatography-Mass Spectrometry) analyses to compare aroma profiles. Ruled out electric heating and biomass as they do not preserve the aromatic profile. Ruled out electric heating and biomass as they do not preserve the aromatic profile.
Biogas and green hydrogen comparison
Evaluated the potential of biogas produced from vineyard waste (grape pomace, stems) via anaerobic digestion. Investigated the use of green hydrogen (produced via electrolysis powered by renewable energy) as a zero-carbon heating source. Analysed the technical integration challenges, safety considerations, and cost implications of each solution.
Regulatory study
Worked with the Bureau National Interprofessionnel du Cognac (BNIC) to understand if the use of biogas or hydrogen would be prevented by the current AOC specifications.
Outcomes
A circular economy project:
- Biogas was preferred to hydrogen because of its lower cost, the resulting recovery of production waste and the absence of process modifications (e.g. burner)
Decarbonisation targets exceeded:
- 85% GHG emissions per litre of alcohol produced (compared to natural gas);
- The remaining 15% will be offset by local agroforestry projects (restoration of hedgerows).
Industry leadership:
- AOC specifications updated to explicitly mention biogas.
- Noxis initiative featured in the Wine & Spirits Magazine as benchmark for sustainable distillation.
- The project sparked interest from 5 other AOC-protected spirit producers exploring similar decarbonisation projects.