Does Gasoline go bad?
Short answer:
Yes
If gasoline was just Octane (C
8H
18) it would never go bad, it would just slowly evaporate away. The problem is, modern gas especially, is a blend of different hydrocarbons and additives, some of which evaporate more quickly and over time changes the
octane rating. Gas can also absorb moisture out of the air over time and some of the additives can break down. There are other additives you can put into it if you're going to store it for a long time to combat this, but there are questions about how well they work. Easy to
google for more information on this.
I usually store 10 gallons at the start of hurricane season, then at the end I put them into my car. So, I store them for 6 months with no additives. It works, but afterwards I refuel with higher octane to burn off any valve/spark-plug gunk. Amusingly, the wife has an EV hybrid, but I have to nag her to take it out of EV mode every so often to burn up the gas before it gets to old.