[VLM]

As a guy who's done some homebrewing, yeast can handle alcohol concentrations which if placed in a mammal bloodstream would result in instant death. Its a matter of about 1.5 orders of magnitude not a minor difference. That has certain implications for what their cellular insides can tolerate vs ours.

So something in the cellular structure of yeasts "shields their innards" a lot better than cells in our body. A moderate booze fest to the deep innards of a yeast cell might for a mammal cell be achieved by merely sniffing an open beer bottle. It would require further research.

Its a particularly bad combo, using yeasts and alcohols to extrapolate to humans. Like "randomly" selecting a halophile to extrapolate human salt tolerance, or "randomly" selecting a thermophile to extrapolate human temperature tolerance.

I see no similar obvious reason not to extrapolate caffeine/yeast combo to humans other than the usual multi-cellular vs unicellular issues.