OK, time for some serious discussion about av-gas.
Aviation fuel is refined to a seperate standard than mo-gas in that if it does not contain lead additives it is 80 octane RON, which is well below the recommended octane rating for small gas engines and WILL detonate and cause major engine damage. 80 octane is red in color.
Next grade up is 110 LL (low lead). The lead content is higher than any of the mo-gas formulas and the lead will leave deposits in the combustion chamber and WILL foul the spark plug. Personal experience with a Honda genset that we used at airshows, that was run consistently on 110LL, is that a couple of times per airshow season, I would have to pull the head and scrape the lead deposits. It would get so bad that the piston would strike the head and the engine would stop. The lead deposits build up in aircraft engines as well but the mandated inspections and preflight checks tend to keep the problems down to a minimum. The deposits can be so bad as to create a tinking noise when you pull the lower spark plugs at 100 hour/annual time and hear the little lead dingle berries fall into the lower cowling.
As for fuel in the shop at the "Goat Pasture"? I have jumped up to 89 octane unleaded, which when sourced from one supplier here in town does not contain any alcohol. I store it in CLEAN containers with tight sealing lids and have no trouble in keeping it for 6 months without losing quality. I know as I have tested for Reed Vapor Pressure and specific gravity the same as we do for race car fuel and av-gas.
Since the test for Reed Vapor Pressure and specific gravity require equipment that tends to be a bit too costly for the average weekend warrior, the only real practical test the average user can perform is for alcohol content. See my post on that here
http://www.mytractorforum.com/showthread.php?t=146217.
Oh yeah. I do happen to hold an FAA Airframe and Powerplant Mechanics ticket and have for the past 40 plus years as well as turn wrenches on sprint cars and modifieds just for giggles and grins.