So I learned something here in TN while working for the County Air Quality Dept. Here (and elsewhere I presume) we have a central pipeline that runs north up from TX called the Colonial Pipeline. It is literally a pipe full of gas running straight from the refinery. In an industrial part of town the pipeline hits several of those huge white tank farms which are run by different name brand gas station companies where they add their additives. Fill trucks stop by on schedule to fill up and take it the station. Smaller local gas station brands will pay to come fill up their trucks at the larger companies fill stations too.
The octane rating changes on a schedule from the main pipeline - it will literally go from 87 to 90 or whatever and, I assume, have a short spell of mix before it fully transfers over.
Case in point, all the stations suck from the same pipe. Only difference are the additives they add and market at the pump. That's how it is in East TN anyway.
This is spot on. As for the mix stuff, they just sell it at the lower octane rating; they call it "octane give-away". It's like lumber; they err on the long side when cutting. It's ok to sell an 97" board as an 8-footer but not a 95" one.
Also, all of the refiners have to test their product before it ships. The samples must meet the relevant standards and be certified by the refinery labs. The samples must be retained for a certain period, they are subject to independent testing and audit, and the refiners are subject to
significant fines for shipping/selling non-compliant product.
All that said, there is ample opportunity for things to go bad during distribution but news travels fast these days and nobody wants to be the station or the brand that gets the reputation for bad product, not the pipeline operator, not the distributor, not the station owner.
And, like BHH says, the additives are where all the difference is. To me, it's all just marketing. Just realize that every molecule of additive in the gallons you buy, is one less molecule of gasoline.
Also note that companies like Costco and the regional grocery stores buy their supply on the market; they aren't "branded" outlets. You could be getting Exxon fuel one time and Phillips 66 the next, or BP or Marathon, etc.
Not trying to start a war or an oil thread
. Just my $.02.
Cheers!