That's my source. Kurt is brilliant, and really nice guy ta boot.
Aw, shucks Stormy, you say the nicest things!
I do want to add that while glass does keep O2 from getting into a liquid, there is already dissolved O2 present in PG or VG naturally, and I suspect that this is the main source of oxidation at room temp in glass over long term.
It is true that VG and PG do not expand at freezer temps. They expand when warm. So leave a couple mL headspace in bottles when freezer-storing. It is better to store them standing up, but that is not always possible depending on freezer real estate. But if they are stored on their sides (I do this), make sure when you use a bottle that it warms back up standing up before you use it. The little air bubble will expand upon warming, and if the bottle is on its side liquid can get forced out from under the cap upon warming.
I did fill to the rim a few times back in the early days (>5 years ago!). I filled the bottles with unthinned 100 mg/mL VG-nic in a cool kitchen in January. Then when I took them out and into my hot office in the summer, liquid expanded and leaked out from under the cap. Not good.
But I would not fear oxidation too much. Keeping all oxidation to a minimum is good if you like completely tasteless nic base that has little TH and pepper effect. But a bit of oxidation can add TH and pepper, that I personally prefer. Nic oxides are not harmful, and it takes VERY little to strongly color a nic, with minimal depletion of nic concentration. For me, some nics get BETTER with some oxidation. Those I just keep some in plastic dropper bottles at room temp for weeks or months.
VaperTek Throat Hit nic is Kevin's regular ultra-pure no-taste nic with O2 literally bubbled through it for a short time. This is one of my favorite nics currently. The slight oxidation gives a TH and pepper bite that I love, but without significant flavor. Has a slight yellow tint.
I think that slight oxidation is part of the tobacco-liquid flavor bloom that happens over time. It is well-known that tobacco flavors can improve with time (some call this steeping), and I think oxidation is a big part of that, in addition to more complete mixing. Nic oxides in high enough concentration will impart a tobacco-like flavor.
But if you want all oxidation to essentially stop for years for the purpose of long-term storage, storing in glass in the freezer is the best way to go. Ar or N2 purging the headspace is probably overkill, but if you want to do that, by all means. The amount of O2 in the headspace is very low, and probably less than what is already in the PG or VG. But the rituals we go through to store our nic long term are good for purging doubt, and I think this is also very important for peace of mind!
I've not tried canning jars, but I would be reluctant to use my hinged-lid Mason jars, with the rubber gasket, since PG and VG are alcohols, and I know that ethanol will dissolve the rubber gasket over time. I use 30-50 mL amber bottles with plastic caps and eurodropper inserts (
Specialty Bottle - European Dropper Bottles). The insert is polyethylene I believe, and acts as a gasket for the cap. But I doubt in the freezer much O2 gets through it or the cap. I have seen no change in my nic in the freezer: >5 years for some and the same as when I bought it. The surodropper inserts also allow for no spills and syringe dispensing, both very important to me.
