There is a theory behind that statement... lets see if I can invoke some brain waves here
Hope you can stay with me, I'm not a chemist
Each flavoring is made up of dozens of molecules to create the desired taste, (not real flavors).
Ok,.. lets say you want to have a strawberry/watermelon juice.
So you get your strawberry, with all of it's molecules, and you add it to your watermelon with all it's molecules.
FRESH (important here) you will have a nice strawberry/watermelon juice ...but
What happens is, as soon as you add the PG/VG/NIC changes start to take place, as these molecules have a bigger playground, and start fighting for space in all the extra room.
Maybe the strawberry wins, maybe the watermelon wins, but in any case all these molecules running around will create a THIRD flavor.
So "fresh" it's strawberry/watermelon/ ......steeped, it changes.
The originals will still be there but mutated with a new element created, and added to the mix.
That's why , unless you mix, shake and vape, you may think your flavorings are not up to par, because it "doesn't taste right" next week/month.
I'm a "steeper". All of my juices are at least a month old because I stay well ahead of myself.
This has not only produced some "different', but great tasting juices, it has also created some problems and a lot of "tweaking"
If we were dealing with some honest to gosh squished strawberry's and smashed watermelon, it would be a lot easier.
Make sense ??
Any hair raising experiences to relate ??
I hear you. Your strawberry, for example, has over 300 compounds to make up that one single flavor, though there may be only ten components listed as ingredients. Much can be learned, over time, from the examination of the components. TFA publishes all of their mixture components on their site here:
Perfumer's Apprentice
Simply click on the List "tab" of any flavoring to see the underlying components. I believe flavoring is much more an art than a science, though. Understanding flavor chemistry doesn't mean you can make a good flavoring, that's where the art comes into it. I rarely spend a lot of time thinking about the molecular structure of our mixes, LOL.
I do understand that blending flavors does result in changes to the underlying solution that affect taste, aroma, and ultimately flavor. We make this whole juice thing way more complicated than it needs to be. It's like making a smoothie in a blender. If we add several different foods, we will be creating different flavorings after blending. Adding a fudge topping to the ice cream makes a chocolate sundae. The sundae is different then than the ingredients we started with individually, and hopefully, even better.
There are really three parts to what is commonly referred to as steeping, as well. There is aeration (breathing), steeping and aging. As long as the juice is not in the light and kept in a cool environment, simply agitating, capping and aging the juice will improve the flavor, in most cases, over time, until flavor maturity. Normally, this shouldn't take more than about a week, and is often quicker, depending on the recipe.
My point about making juice is that good juice is good immediately. It may improve and become great over time, but bad juice, initially, never becomes great in my experience. When I first started, I made juices that required weeks, sometimes, to "improve." Many said this was normal. The actual problem, though, as I was to later learn, was a bad mix, not a steeping/aging deficiency. If I need four weeks for the eggnog to diminish to the point that it doesn't taste bad in my vanilla custard, then what I really have is a recipe/formula failure/error, and not a long steep requirement. This is just my experience. Here's a tutorial on the subject that is short and concise on steeping, breathing, and aging, even if Rip is crazy:
Because the initial flavoring must be good at inception, imho, I always encourage members to test their juice immediately out of the beaker. If it's not good, I recommend trying another recipe. it's just silly to make juice, and then wait a week or two to see if it's any good. I don't want to take a month to make a new vapeable juice. I did do that a few times! When it's good right off the bat, you may have a great juice, but only time will tell. Bad juices never become great, no matter how much time we waste waiting for it to stop tasting bad. Again, that's been my experience time and time again.
We can completely avoid the world of chemistry and molecules in our juice making, make our recipes, aerate (breath) for a short time, cap and place in a cool dark place like a kitchen cabinet (steeping), and then just allow it to age. If you have premixed your flavorings as I do, and allow them to stay in a cool dark place for a while (aging), nothing else will be required. The premixing will allow the final juice mixture (with VG and Nicotine in my case) to reach maturity in hours to perhaps a day or two on the outside, and far quicker than completely mixing everything together and allowing the nicotine to oxidize, making the juice darker and darker over time, even reducing the flavor and nicotine strength.
That being said, I know of no juice that won't benefit from time (steeping and aging), perhaps a week, to improve, and reach maturity. Premixing of flavor bases does this, as well. I generally will shake the bottle for 30 seconds, allow it to breath until the air bubbles dissipate on the surface (maybe an hour?), then cap and age in a cool dark place. That's really all that is required. I don't heat, or use ultrasound, lasers, cavitation, or a thermal micro shaker platform. It is simply not necessary. This is a hobby for me, and vaping is something I took up in 2009 to stop smoking.
I think I posted that about a year ago 
