So I just received my first order of VG and PG. Until now I had been using what I had leftover from BCV and from Wal-Mart. I got 1 gallon of VG and 1 liter of PG. A couple of months ago I never would have thought I'd be ordering this stuff by the gallon. I always figured I would have a few small bottles laying around and that I would be mixing a few bottles of juice every now and then. I was wrong.
After much consideration, I ordered from Duda Diesel which is about 45 minutes from where I live. Thus, I had it in my hands the day after I ordered it via Fed Ex. Total cost for 1 gal VG and 1 liter of PG was $36 shipped. (I had to pay state sales tax of like $2).
I decided on them over Essential Depot and other vendors because they provide a full COA on their website which explains exactly where they get it, how it's shipped, etc. It is 99.7% pure USP and kosher certified. They source it from ADM (Archer Daniel Midland) who is a "Big Ag" giant that is also big into biodisel. ADM has (American) factories that distill crude glycerine (from soybean) into a highly pure USP grade product. It is then sent by tanker truck (or rail) to distributors like Brenntag who then sends it to smaller retail companies like Duda (Duda told me they buy it by the truckload directly from Brenntag).
Duda is a biodiesel business that sells products for biodiesel DIY'ers and other people interested in making their own fuel. They have also branched out into solar panels, wind power, geothermal systems, etc. The dude started the company from home after he was trying to make fuel for himself and became frustrated that there was no place to buy supplies for individuals. Now has a pretty nice sized warehouse and operation.
Since glycerin is a natural by-product of biodiesel production, then it makes sense they would carry glycerin. They carry PG because people use it in anti-freeze (OMG, anti-freeze!). I figure if I decide to go max VG, I can just mix my PG with 50% distilled water and throw it in my car. Their PG comes directly from Dow Chemical (makers of Optim) and is likely about as pure as one can reasonably obtain (all American sourced too -- 'Murica, FTW).
Essential Depot will not reveal from whom they source their glycerin. I don't like that. Same thing with Humco (Wal-Mart glycerin). I emailed Humco and asked them directly and they told me they repackage it, but cannot reveal their supplier. I understand they keep it secret for business and competitive reasons, and that's fine and I wouldn't care if I were making soap. But we are inhaling this stuff, so I want it to be as pure as possible and treated properly along the chain of custody.
I don't know, I am just one of those kinda guys that likes to know "how things are made." Maybe you don't care, and that's fine, but I am sort of OCD about knowing everything I can know, especially if I am going to be inhaling it. I feel about as comfortable inhaling PG/VG sourced from Duda as I do anywhere else. At least I know it was made and packaged in 'Murica. We make good shit (well, second to Germany and maybe Japan, but still good).
My personal rule is that as long as it's USP, you're good to go.
What more do you really want? If you were given the name of the supplier, then what? Would you take their word on purity? Ask for a tour of the lab? Google them hoping to find comparitive reviews?
AFAIK, as long as you go for the purest possible (which would be USP, there is no higher authority) glycerin is glycerin, and glycol is glycol. If it's 99.7%, the brand and manufacturer should be irrelevent.
Well, the USP standard only requires 99% purity. Most USP glycerin I come across is 99.5 or 99.7%, thus for some reason they have raised the purity beyond what is necessary to be in compliance.
If various companies have done that, then there could be differences in quality between them. Or maybe not. I just like to know either way.
I'm pretty sure that the .5%, .3%, .1%, etc. is just water absorbed during production, since VG is hygroscopic. I can't say I'm 100% certain since I'm not a chemist, but I've read that in a few places and it sounds right.
As far as taste goes, 99.5% is no different than 99.7%. I've worked with atleast 5 different brands of USP glycerin and glycol, and find them indistinguishable.
I think the only way for you to be really, really, REALLY sure would be to send a sample away for GCMS. Personally though, I don't think it'd be worth it.
Very pleased at the homework you've done and the prices seem pretty nice. At wholesale I currently get VG at $18/gal and I think ~$20/gal for PG. But.. I occasionally get a tub that has a couple black particles in the bottom. I'm a shtickler for purity and it bugs me to no end. I'm always driving back 40 miles to exchange it. It's a pain.
I should add that it's not some poop VG I get, it's from a very reputable e-liquid company on the west coast. They have a full half a mil iso7 lab, which makes me wonder why I get any impurities whatsoever.
I've ordered some stuff from Duda's Amazon store (mostly syringes) and have been pleased. They always ship quick and their prices are pretty good if you're looking for Luer Lock syringes with blunt needles already attached.
As far as Humco, I've used it and it's fine IMO (and count me as one of those people that can't tell a damn bit of difference between any brand of VG I've tried.) Don't take this as gospel, but I could've sworn someone found out that Humco gets their VG from Dow Chemical. Considering how many huge retail companies Humco rebrands for, it makes sense that they'd source from who'd I'd imagine is probably one of the largest VG manufacturers in the country.