"Peter Dohm" wrote

Really, the only way that I know to correctly "do the science" is to
purchase a small amount (perhaps a liter) of anhydrous ethanol from a
medical supply and perform a series of tests on a variety of
samples--including samples of known pure and dry avgas and mogas. For the
moment, I am unwilling to undertake the project, and also I believe that
Clare and Bob are correct.

How sure are we that the gasohol in service station tanks contain no water?

Is it possible that all tanks containing gasohol contain at least some water
dissolved?

Is it a certainty that the alcohol added to gasoline contains no dissolved
water?

I don't know the answer to any of these questions. Does anyone know, for
CERTAIN, any of these questions?

My guess is that all service station tanks, (unless they have never had
straight gas, and that they are BRAND NEW) have had an opportunity to get
some water in their tanks. If that is the case, and you put gasohol in
them, the gasohol samples will contain some dissolved water, and the seltzer
test will work.

If that is the case, doing a scientific test with clean gas and adding water
free alcohol will prove nothing.
--
Jim in NC