Any years Old gas

[jwwseville60]

Im sure most everyone knows this...but please stay away from little gas stations
in rural areas that dont sell a lot of inventory.
Ive tested the gas with a test tube and there's always water in it.
Always buy from a good station with lots of pumps and traffic. The tankers refill every week or more.
And dont spare the Marvels!

[TJ Hopland]

Yep.  Ethanol that a vast majority of our gas in the USA has at least 10% of is way more hygroscopic (sucks moisture out of the air) than the base gas.  If its exposed to humid air for very long it will suck up all it can and then it all separates.   Try spilling some E85 on a humid day, it pretty much instantly turns to snot.

Are the gas storage tanks still just vented?   I would think that would be against the rules in CA for many years.  So do they still have the issue?  I have seen that more recently even things like lawnmowers don't have vented gas tanks so I would think if they are cracking down on that nationally they would have already got the gas stations not just openly venting which you would think would reduce the amount of humidity that gets in. 

I also wonder how much difference underground vs above ground tanks make?   Underground you would think would me much more stable temp wise so less expansion and contraction possibly pulling in humid air and less condensation.   Above ground maybe has more of those issue?