Thank you, Sun! Your information tells me a lot! I do not understand the temperature dependence yet, but I think I have an idea of what has happened, and indeed something I have been concerned about.
I'm going to get chemical technical here, because I suspect there are some that can follow this logic.
Flavors are are generally esters, especially fruit flavors, as well as ketones and aldehydes. I would imagine (don't really know, but imagine) that tobacco flavors are also esters, etc. There was likely water present in the juice. Vinegar is the product of acetate ester hydrolysis (reaction with H2O). MANY flavors are acetate esters, with varying ether groups. Banana: isopentyl acetate. Orange: octyl acetate. The other product of hydroysis of the same ester is an alcohol (alcohol is a generic organic chem name for carbon groups with an OH...VG is a trialcohol, or triol). Any alcohol larger than propanol (rubbing alcohol) STINKS!!
banana oil + H2O ----> isopentyl alcohol + acetic acid (vinegar)
Isopentyl alcohol stinks like...hmmm...someone who has not washed in a long time. It has a FUNK!
Not saying you had banana, as you clearly didn't, but you obviously had an environment where water and pH (nicotine is basic) were hydrolyzing esters. Acetic acid is vinegar, but other esters may be decompose to butyric acid, propionic acid, etc (not all esters are acetate esters). Butyric acid smells like vomit. A tiny amount of butyric acid will smell like parm cheese (butyr name means butter...greek or latin, i forget).
I do not know about the tobacco flavors but they are likely to be a complex mix of various flavor compounds.
Now to why this happened in the cold and not room temp. I honestly don't know, but if a reaction is exothermic, it will be react more in cold. And it is very true that cold liquid, especially di- and triols (PG, VG) WILL absorb water when cold.
So it seems water, not cold, is if not THE enemy, AN enemy, more so than microbes, as was discussed earlier. And if the pH of the solution is right, ester hydrolysis will occur, and since esters hydrolyze to alcohols and acids easier than acids and alcohols form esters, cold will enhance this hydrolysis to stink compounds.
So it seems, at least, that flavors can indeed hydrolyze in the cold/wet environment of a fridge. Even unopened ones, although my guess is this depends on the source's recipe.
While this does not say anything about unflavored high nic juice, unopened, it does say a lot about flavored juices. Evidently even unopened ones have enough water in them to have this occur, especially if the pH is right.
On a side note, I ordered some unflavored juice from Vermont Vapor, mainly because the use only glycerin, nicotine (99% pharm pure) and a little citric acid to balance pH. I wonder how flavor mixes with that juice will store?
So given this valuable detailed info from Sun,
it is clear that the fridge is, at least certainly for flavored liquids, not recommended for long term storage. And given that available commercial info say cool, dark, dry, I am going to store all my reserves as such.
Long term storage of unopened reserves will be, at least with today's info , unopened bottles in a box in the basement, maybe even with drying packs like are in some vitamin jars. A desiccator!
In fact, if you are using a tackle box for supplies/juices/etc, like I am, I think a few of those drying packs would be good in there as well.
I'm sure disiccants are available in hobby shops...look for the flower-drying supplies. Silicon oxide is the usual stuff, although even salt will absorb water! In my world of chemistry, CaCl2 or MgSO4 are both good for this. CoCl2 is also another really good one, since it is colored blue when dry, but turns pink upon hydration, so you know it is done drying the environment...put it in an oven with heat for a bit and it goes back to blue. I don't know if it is available to the general population.
Sun, I believe we have made great progress on this vital issue! There are still many variable I need to understand, but dark, dry, and arid seems the total way to go for all liquids at this point.
For me, given the possible/likely banning, vaping is much more pleasurable if I know my liquids are going to be stable for a LONG time!
I understand this may have been too technical for some here, but the answers are only going to come from hard-core chemistry.
Thanks so much for your info, Sun! Rock on, my friend!
Kurt
