Some people seems to think that in order to improve an e-juice flavor, the e-juice must sit for weeks before use it.
I really do not understand where that come from since most of the e-juice ingredients do not seem to be chemically reactive.
Have anyone any good explanation on why should the e-juice flavor improve with the sit?
Hiya Apple, welcome to the forum!
I'm not a chemist, but I do play one on the internet, so I'll take a shot at this one.
I can't tell you which electron goes where, but that's pretty much what's going on in any chemical reaction; electrons in the outer shells of atoms either swapping or not swapping with the outer shells of other atoms, whether it's a stand-alone atom or an atom that makes up a molecule (nicotine, for example, is a molecule; so is water, and would be proplylene glycol, and glycerine).
The flavorings that are in an e-liquid are also composed of molecules; as is virtually everything in the universe that isn't a stand-alone atom. E-liquids will change flavor and color over time because of these chemical reactions. Nicotine itself is reactive with other molecules, and that is evidenced by the fact that a zero-nicotine liquid will stay a lighter color than the same liquid with nicotine in it.
The short answer to your question is that the flavor will change as these chemical reactions occur, and "bonds" are formed between different molecules, depending in large part on the "valence" of the atoms involved.
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Checking my work .......
From that source we all "love to hate" - Wikipedia:
"A chemical bond is an attraction between atoms that allows the formation of chemical substances that contain two or more atoms. The bond is caused by the electrostatic force of attraction between opposite charges, either between electrons and nuclei, or as the result of a dipole attraction. The strength of chemical bonds varies considerably; there are "strong bonds" such as covalent or ionic bonds and "weak bonds" such as dipole–dipole interactions, the London dispersion force and hydrogen bonding.
Since opposite charges attract via a simple electromagnetic force, the negatively charged electrons that are orbiting the nucleus and the positively charged protons in the nucleus attract each other. Also, an electron positioned between two nuclei will be attracted to both of them. Thus, the most stable configuration of nuclei and electrons is one in which the electrons spend more time between nuclei, than anywhere else in space. These electrons cause the nuclei to be attracted to each other, and this attraction results in the bond. However, this assembly cannot collapse to a size dictated by the volumes of these individual particles. Due to the matter wave nature of electrons and their smaller mass, they occupy a much larger amount of volume compared with the nuclei, and this volume occupied by the electrons keeps the atomic nuclei relatively far apart, as compared with the size of the nuclei themselves.
In general, strong chemical bonding is associated with the sharing or transfer of electrons between the participating atoms. The atoms in molecules, crystals, metals and diatomic gases— indeed most of the physical environment around us— are held together by chemical bonds, which dictate the structure and the bulk properties of matter.
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Lastly, if you talk to a juice maker, they'll probably tell you that some juices are "good to go" right away, and some need to sit ("steep", like tea) for a while - days or even weeks - to reach their prime. That said, IMO juice will start to go bad if it sits around to long, especially at warm temperatures. I haven't looked into it fully, but I have a feeling there's an ideal temperature and humidity level for any given juice, and it probably varies according to flavor, PG/VG ratio, and nicotine content, among other things.
Some people "steep" juice with the cap off, but I'd do that in moderation. For me, a safe bet would seem to be to store juice in a cool, dark place. I'm planning on getting a dorm fridge that I can set to a fairly warm (for a fridge) temperature, like maybe 55 degrees or so. Juice is fairly expensive, and I have had a lot of it become unusable. So much so that I could have bought a couple of fridges buy now with the money I've lost.
If you search on "juice (/e-liquid/e-juice) steeping (/storage/storing)", either on this site or with Google, you will get a LOT of information.
