Re: Gasoline
The fuel loses 2 things with age.
1. The Volatile top, very low octane low flash point component that gets the fire going when sparked a little.
2. Short chain molecules----originally created by cracking long chain polymers into shorter chains, tend to recombine with time, forming long chains (varnish, etc). This is the item that fuel stabilizer addresses.
The third item that occurs with ethanol laced fuels is that they will absorb moisture and separate out a lower layer of ethanol-water mix. The interface between them will form some pretty nasty sludges. The water doesn't burn well, and the gasoline that's left is lower in octane because much of the octane boost was gained from ethanol.
If it smells decent, probably neither has occurred. The tighter the container, the less storage deterioration will occur.
If at all possible, I keep ethanol away from any engine that is not used daily. I'll run gasohol all summer in my conversion van, but when winter rears it's ugly head, I run a tank of non-alcohol gas through it, then fill it up with the expensive stuff for the winter. I keep it full, because it is also my emergency escape the city van.
