This is probably just poor air flow.
Often caused by the pan too close to the flame. OR, wind screen too tight.
Proof (60%-95%) souldn't bother things. Have you ever lit a shot of bourbon?
Water slows a burn down but this does not effect the fuel/oxygen mix that much.
Methanol (yellow heet) burns quicker than ethanol. The fumes *can* be poisenous, but burn clean. (SLX, high quality denatured thinners, AKA marine stove fuels, have a portion added.)
Isopropynol is rubbing alcohol...do not use this. All sorts of nasty byproducts.