For those of you just getting into DIY juice, let me share some of my journey.
In the beginning I was super .... about everything. I measured volumetricly (although mass measurement would have been even more precise), I tracked everything to the drop in a SS, acquired all sorts of lab paraphernalia, I tested nic concentration on every batch, I tried ultrasonic and thermal baths for speed steeping, magnetic stirrers for mixing, etc.. etc..
Over time what I figured out was that I was making WAY too big of a thing out of it. It does not have to be a science project.
- "Assuming" you are making it for yourself, precision of nic concentration is no big deal. Close is good enough. Even if you are off by 5% in your measurements, 5% more/less of what the recipe calls for is no big deal. Vapers "self regulate". If a juice is 5% weaker your body will know and you will unconsciously vape a little more, if it is 5% stronger you will vape a little less.
- If you leave a little headroom in the bottle, a couple of good shakes is all that is needed to mix the juice. I use an Erlenmeyer flask to mix my "master batch". I put the ingredients in, put my thumb over the opening and give it a good shake before bottling. The small concentrations of nic have never bothered my thumb, but you could use a rubber flask stopper if it worried you.
- Some juices, do benefit from steeping. Ones I have noticed that benefit are tobaccos, most berries, peanut-butter and caramel. My everyday peach, and many others, do not benefit at all. My rule of thumb is if a juice gets darker in color as it ages, it will benefit from steeping. The easiest way to steep is just let it sit for a month. Speed steeping methods can accelerate it if desired.
- Speed steeping can be done as easily as putting your bottle or flask, preferably glass, in a crock pot water bath for a few hours. Ultrasonic works great if you have a high end one, low end ones dont do much. But even my powerful commercial grade ultrasonic was only marginally better than the crock pot, not enough to justify the expense. Speed steeping, actually the heat, will reduce your nic concentration by a ~5-7% ratio. Again, if it is for yourself, who cares, or you can compensate but mixing it a wee bit stronger than what you want to vape.
- I do use an eJuice recipe program. It not only helps with the math, but can allow the saving of recipes if desired. Nowadays, I rarely use a recipe for the flavorings, I just wing it, but I do use the program to make sure I have the right nic/pg/vg ratios.
What I tend do today is make a "master batch" (ie a 1pint bottle) of unflavored nic at my desired pg/vg ratio, but I make the nic ratio 10% stronger than what I want to vape. This way I can take a small 30ml Unicorn bottle and add 1.5ml - 3ml of flavor and then fill the bottle with my master batch. Give it a good shake and Boom, done....... and I know that I am within 5% of my desired nic ratio. If I am trying to "nail" a recipe I still use this method, I just track my flavoring amounts carefully with a 1ml syringe.
The one thing I am still .... about is labeling my bottles. Nothing worse than picking up a bottle and having no clue what is in it, in fact that has the potential to be dangerous.
I learned that it really doesnt need to be a big deal, and I dont need a lot of labware.