Because the first time I saw "Between B10 and B20" on a pump (it was either at that TA or the Pilot on 255 just east and a little south of Pontoon Beach), I asked which it was. (At one place it said B20 and the other it had the range listed.) Turns out it can be anywhere between B2 and B20 when it's delivered (although B2 is rare anymore - there used to be an IL law about state vehicles all being required to use B2, but that was bumped to B10 at a minimum last year), and some places have the range listed on the pump, while others just have B10 or whatever listed and don't bother to change the B-sticker if they get a different percentage. In a Sprinter, you have to be careful, which is why I ask, nearly every time, before I fuel up in IL and IN (and most places west of Walcott, actually).
If on the pump it just says biodiesel and doesn't specifically say what percentage, I'll for sure ask. If a percentage isn't listed, it's supposed to be B20, but some places out in western IA and KS and NE, and even a few places around MN, it might be B25 or B30. And I don't even want B20. If B20 is all they have, I'll ask if they know where any non-biodiesel is, and then go there. Ran into that in Scottsbluff, NE where everything in town was B20 or B30, except at the Co-Op where they had regular.
Sometimes the clerk at the fuel desk doesn't even know what they have in the tanks. All they know is what's supposed to be in there. If they aren't sure, I usually don't take the chance.
Last month (Dec 08) the FTC regulations for correct biodiesel labeling at the pump went into effect. B20 is the standard, and if the pump is labeled as B20, or just plain "biodiesel" without a percentage, then B20 is what is supposed to be in there, but it can be anywhere from B5 to B20. And listing a range is fine by the FTC.
In the winter months, especially up north, most places cut it to B5 or B10, but some leave it at B20. The Illinois Soybean Association apparently has a lot of clout in that state (Illinois is the national leader in biodiesel), and too much diesel ends up at more than B20, and in the winter when they usually cut it to B10 or less, if often ends up being more (the fuel delivery invoice will tell the manager what's in there, tho). Same thing happens in a few other soybean-centric states.
Most big diesels, especially newer ones, don't have any problems with B25 or higher. But older engines, and smaller vehicle engines like cars, Sprinters and pickups, it can matter a great deal. Biodiesel is a solvent that will eat rubber seals right up.
But for a Sprinter (and most Chrysler diesels) B5 is what they recommend as a max, and it's nearly impossible to find B5 at the pumps. I prefer regular diesel, but don't freak out when all I can find is B10, but I want to make sure that it's no more than B10, cause even at B10 I use extra Howes. But B20 is rapidly becoming the standard all over. And up north, espcially in IL and a few other places, it's B20 even in the winter, and sometimes it's a little more than that.
