As a general rule, gasoline isn’t stored as long as diesel fuels are. But that doesn’t mean there aren’t concerns over its quality while it is being stored.
Like diesel, today’s gasoline fuels are significantly different than they were in years or decades past. The biggest change in gasoline properties over the last decade has involved the increase in the addition of oxygenates to gasoline – a requirement of the Energy Policy Act passed back in 2005.
Now, instead of finding pure gas at the pump, consumers are finding ethanol blends containing up to 10-15% ethanol. And this means big changes when it comes to how to store that gasoline.
Today’s gasolines are more likely to be adversely impacted by water accumulation in storage tanks. Water has always been an enemy of stored fuel, in no small part because microbes need it around to grow and thrive.
Not only do stored gasolines have to worry about that, they can be severely impacted by phase separation in storage – the separation of gasoline and ethanol which happens when too much water impacts ethanol-blended gasoline in storage.
Phase separation strips the gasoline of octane value and can make it generally unuseable.
Stored gasoline can also be impacted by a long-term loss of octane value over time, even if it doesn’t contain ethanol or other oxygenates. Two-strokes and small engines may not be affected so much by this phenomenon, but larger four-stroke engines and vehicles that may need to run on stored gasoline may certainly be impacted to the negative.