Ok, Reni, I'll chime in, but I'm always reluctant, because steepers have such fixed opinions about their heating/timing processes.
I do not use heat, or substantial agitation (only a 30 second good shake) with my juices. Over time, the different flavorings will bond together to form blends of the flavorings, sometimes with predictable results, sometimes with unexpected results. When I was a new juice maker, I found it very hard to make good juice because of the time required for steeping. Making new juices, or even really good juices was so slow because I had to wait for steeping to occur. Some juices took a few days to steep, others weeks to steep.
In order to speed up the steeping process, many juice makers elected to use heat to "speed steep" their juices. Does this work? Yes and No. Sure, heat will increase chemical activity in solution, no question, but at a price. The price is in entropy. By introducing heat into steeping, you are adding "energy" that would not exist if you just allowed time to steep your juices. Because of an increase in entropy, the final juice made with heat will ALWAYS be different than the juices made without heat. This is just basic thermodynamic physical law. Adding heat to a mix is no different than adding a different ingredient, because it is a different ingredient. You can make the argument that one is trading a slightly different mix to vastly shortened steep time, and, who can argue with this? The point is that the juice IS DIFFERENT after using heat, with a shorter steep time, than juice without heat and a longer steep time, and it may or may not make the juice better.
Where I have differences with some steepers is the contention that great juice REQUIRES a long steep time. I have not found that to be the case, provided we use high flavoring percentage mixes. All of my juices have flavor percentages between 20 and 30% of overall mix. In my case, this is my PG component, and the balance (70%) is my VG component. This varies by user, and does also affect flavor, throat hit and vapor production. Vaping temperature also affects the juice flavoring (watts).
I prefer making good juice with short steeping time frames. It's the only way it works for me, otherwise it would take weeks to make a decent juice. I will settle for really good juice at time of mix, and the expectation that it might "steep" and flavor bond (a condition of low entropy) and become great juice. Often this is the case. To do this is really simple, use enough flavoring where steep time to "bring out" flavorings is not required, as they are already there at the time of the mix. Whenever I run into folks that insist that their juices require weeks to steep to become Nirvana, I often find out that they use low flavor percentage mixes. This actually makes perfect sense. The flavor percentage is low at the time of mixing, and it takes time for these flavors to emerge, with or without heat. SOLUTION: HIGH FLAVOR PERCENTAGE MIXES.
For me, it either tastes good at mix, or I change it. I don't have time to wait days and weeks for the flavors to emerge. When I dumped that thinking, my juice improved immediately, as I can immediately remix flavorings until they are good....I don't have to wait. Also, I want to introduce as few variables into the juices as possible. Why? Because I don't want the flavoring (which is good at mix) to change substantially over time, or by adding thermodynamic variables, entropy, catalytic action, or what have you. I just want the juice to flavor bond (couple of hours usually), and then taste great, and stay great. In my experience, as Reni said, less than good juice....NEVER becomes great juice. And why should it need to? Why not keep trying to make a mix that DOES TASTE GOOD initially? The obvious advantage is NO WAITING. It's good out of the can, you know it's good, it may become great, but it's NOT BAD! Good is good, bad is bad.....NEXT! Easy peasy!
