Recovering and reusing CO from the various stages of winemaking is at the heart of
new thinking. This requires a change of perspective on the uses of this gas, which must no longer become a mere waste product, or just a threat to safety. But for this to happen, it is essential to develop technical and economic models that are favorable to winegrowers and the wine industry in terms of CO recovery. CO occupies an important place among the products of wine fermenta- tion. Yeast activity releases large quantities of this gas, at a rate of several kilos per hectoliter. Values vary according to initial sugar content, but the average is around 6 kg CO/hL for white wine, 8 kg/hL for red wine. On the scale of a small vat-house, this means 600-800 kg for 100 hL of harvest. So if we're talking in terms of thousands of hectolitres, we're talking in terms of tens of tons. This production represents a real challenge for the industry, on several levels. First of all, it's a safety objective for winegrowers and operators. CO, a gas heavier than air, can stagnate and accumulate in vats, or in poorly ventilated areas of wineries.

It then represents a real risk of asphyxiation, potentially fatal. It is considered a hazardous chemical agent under the French Labor Code, and winegrowers must take appropriate measures. Information campaigns have been set up by the MSA to warn of the risks and encourage the implementation of aeration or ventilation operations as a minimum.
emissions. At a time of low-carbon agriculture, the capture of fermentative CO could prove relevant in balancing the carbon balances of winegrowing estates, and in their own way combat greenhouse gas emissions. Finally, there is a technical and economic challenge. Every year, winegrowers purchase large quantities of this same gas during vinification, in various forms,
sometimes for several thousand euros.