What happens if you carbonate ethanol?

The electronics youtuber bigclivedotcom has an on-and-off-again series where he carbonates various types of alcohol and comments on the taste. One thing he's noticed is that the stronger the alcohol, the more carbon dioxide it will absorb; so, he recently tried carbonating 'moonshine' (70% lab ethanol, 30% water).


This absorbed a staggering 22g of CO₂ per litre (and ended up completely undrinkable, or at least more so than it was previously).


I know that when you carbonate water you end up with a weak carbonic acid solution based on the H₂O + CO₂ ←→ H₂CO₃ equilibrium. But the references I've found says that carbon dioxide is much less soluble in ethanol than in water because ethanol is less polar. So, I'd expect that the stronger the ethanol solution, the less carbon dioxide would be absorbed. This is the complete opposite of what he actually observed.


So, what's happening here?


Reference: <https://www.youtube.com/watch?v=yArcH80PiP4>




Carbon dioxide is in fact roughly ten times as soluble in ethanol as in water [[1](https://i.stack.imgur.com/dVz9M.jpg)](<https://doi.org/10.1016/j.fluid.2006.04.017>) (meaning you need more dissolved under pressure to get that bubbling effect; alcoholic beverages that bubble or sparkle are mostly water). The figure below from the reference illustrates the increasing solubility of carbon dioxide under pressure as we increase the ethanol content in an ethanol-water mixture.


[![enter image description here](https://i.stack.imgur.com/dVz9M.jpg)](https://i.stack.imgur.com/dVz9M.jpg)


Carbon dioxide is actually non-dipolar, and while [the strong quadrupole enhances its solubility in water](https://chemistry.stackexchange.com/a/151530/17175), it still fits better with less polar solvents such as ethanol.


**Reference**


1. I. Dalmolin, E. Skovroinski, A. Biasi, M.L. Corazza, C. Dariva, J. Vladimir Oliveira (2005). "Solubility of carbon dioxide in binary and ternary mixtures with ethanol and water". *Fluid Phase Equilibria*
**245**, 2, 193-200,
ISSN 0378-3812,
<https://doi.org/10.1016/j.fluid.2006.04.017>.


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