gasoline

phase separation is like this:

1. water does /not/ mix with gasoline.

but

1. ethanol mixes with water

1. ethanol mixes with gasoline.

and if you have ethanol in your gasoline, you can now add some water and it will mix, provided you do not exceed a certain proportion called "saturation".

if you exceed saturation, because natural moisture absorption and thermal cycling exceeds what can be dissolved, the water will separate out into a different "phase", just like olive oil and vinegar from your salad dressing.

isn't it fantastic? if you're an oilco, you get to sell water to people [current san francisco bay area prices] at $4.15 a gallon. the local water utilities can't even get $0.10 for it.

and the real icing on the cake is that if people leave this crap around for a few months, they might have to throw it away and buy more!

Yes. Use a fuel stabilizer like Sta-Bil. Available at your local auto parts store.

--scott