[RedDevil]

IF the E10 sold in the US is water free it would have quite some capacity to absorb water before phase separation takes place.
I buy purposely hydrated hE15 and run fine on it, no phase separation, nor bad economy.

I cannot understand how water can lower the octane number, it does not make sense. Water has no ignition point. It cannot lower the ignition point of any fuel it is mixed with.
I'd expect problems on the other end, bad or slow ignition if there was too much water.

In my student years I had an old moped which tank rusted through from the inside. Drained it as I wanted to repair it; found the inside was covered with condense, and indeed the remaining fuel had some water in it. At night the gasoline vapour condenses back in the fuel and sucks in air. As temperature continues to drop the moisture in the air will condense on the inside of the tank. A few drops per night, but accumulating over time.
If we had ethanol blends in those days it would not have happened.

Doessn't anybody have the notion that if regular is good and E10 is bad, it might just not be the ethanol which is to blame but the poor quality of the gas that goes with it?
Do you believe they mix in the same quality as they use for ethanol free gas?