Yesterday I dropped by the BP station in Warrenton to pick up a gallon of ethanol-free gasoline for the chain saws and string trimmers. There's a lot of folklore surrounding E10 (which is a default case for pump gas these days).

What is gasoline anyway? A naive guess might be that it was more or less pure 2,2,4-Trimethylpentane (aka isooctane) with some "other less desirable stuff" thrown in so as to have an "octane number" of 87 or 93. That might have been approaching correct in the 60s, but that is not true today.

The answer is that what is in pump gasoline varies considerably by season (winter vs. summer gasoline formulations) and by region - summer gasoline with a higher vapor pressure is mandated across the country in places with dense enough populations that there are difficulties with air quality in the summer, and on the coasts entire states or regions.

There's plenty of lore that suggests that ethanol is bad for small engines (eats seals in the carburetors, etc). All of my engines save for one are new enough that this shouldn't be a problem. Other problems with ethanol-containing fuel may be traceable to it being hygroscopic and people storing it in non-safety cans where all the good, lighter fractions boil off on a hot day and the remaining fuel sucks up humidity from the air. I've never had a problem with gas stored in a safety can, but why take chances?

Warrenton is not the closest place to get ethanol-free gasoline (there's a web site for finding it and an accompanying app). It was, however, agreeable with my errands for the day. Oddly, there is no place to buy ethanol-free gasoline in Loudoun County. Strange.

As luck would have it, when I pulled in to the BP station there was a guy in the small truck from Holtzman getting snacks. I know the ethanol-free fuel at that BP comes from Holtzman, and moreover I know they have a fuel rack on Catoctin Circle in Leesburg, so I asked him if there was a place that I could get ethanol-free gas up that way.

Nope. They can't even deliver it in Loudoun County to a private tank.

It turns out that reformulated gasoline is required in parts of Virginia, but not all. DEQ (the Smokey Air people, not the Smokey Bear people, the same people who keep me from burning yard waste until October) has a page on this. Loudoun County is one of those places.

There's no per-se requirement to have ethanol in fuel to make RFG. Before ethanol became popular 15+ years ago, MTBE was a popular choice of oxygenate, but it made fuel spill and tank leak plumes that much worse. ETBE could be used, but is more expensive than either MTBE or ethanol.

There's a business cost associated with each gasoline "recipe". Expecting a special recipe to be maintained for a niche product that only has appeal in certain jurisdictions would be unreasonable. Hence, no ethanol-free gas for sale in Northern Virginia.

I feel a bit like someone smuggling Cuban cigars back from Canada as I go to Clarke or Fauquier County to buy non-compliant (but highly desirable) fuel.