Hey guys!
I've been mixing for a year or so, and I've had a very weird thing happen to me a few days ago. I mixed a batch of juices with some PG I'd purchased locally a couple of months ago, and I noticed that all of them had this bitter, weird taste to them. I thought maybe my nicotine had gone bad, and started making plans to buy some more.
I mix by weight, so when I'm mixing, I keep some PG in a dropper bottle and then refill it from my big bottle whenever it runs out. When I opened the big one, it made a slight hiss, as if I were reopening a soda bottle. That was the first red flag. The second one was the intense chemical/alcohol smell that came from it. I tasted a drop on my finger, and the taste was horrid, like pure alcohol, and incredibly bitter, but not the normal bitter sweetness from fresh PG.
Needless to say, I immediately discarded it, along with my whole batch of juice. In fact, I'd mixed other stuff with that PG before, and decided to throw it all away, just to be safe. Got myself some fresh PG from another, more trusted supplier, mixed it all again, and the weird taste was gone.
So, my question is: what the hell happened? This bottle was maybe three or four months old, and I keep my PG closed in a dark cabinet, occasionally taking it out to transfer 30ml to a dropper bottle before mixing. Does PG spoil? Did it get contaminated? The soda bottle hiss when I opened it, along with the extremely strong alcohol taste and smell, led me to think it had somehow fermented, even though that's obviously not possible. Or is it? I'm confused.
PG is sensitive to UV. Byproducts from oxidation include dioxolaned, aldehydes, acids and ketones.
If metal falls into PG it can oxidize faster, too.
You might be tasting a ketone product.
Interesting, thanks for the answer. Why would oxidation from UV happen if it's sitting inside a dark cabinet? Not questioning your input, I just want to know if there's a safer way for me to store my stuff from now on.
I would say no, because I've personally never seen it happen with my PG stored at room temperatures.
That being said, no PG is 100% pure so I'm sure there are outliers with more rapid degradation and oxidation. If you don't toss the stuff let me see if I can send you a label to ship it to me and maybe I can swing a lab test to find out wtf it can be.
That is extremely weird, especially the hissing sound that it made.
Definitely not normal and never occured to me. PG might degrade over time, especially depending on storage, but I don't imagine it beginning to hiss like a soda.
Sad to hear you discarded the bottle and /u/abdada can't test it. I'm glad he's more relaxed then me, since he's the chem pro around the community. This thing freaks me out.
Good call you discarded it.