Isn't anybody else surprised that Wlad made a custard? I thought they could not be made safely
It took awhile for me to piece all this together, but custards can most definitely can be made safely! There's a slew of options out there now. FlavourArt has one of the most authentic custards (I've come to realize) and it does not have diketones. FA does 'eggy' very well and that is what a custard arguably should taste like,
not butter! The most popular of all DIY/pre-made custards comes from Capella (their v1). I bought it just to see what it was like and it is so damned far from an actual custard I don't know what people are tripping off of. Well, yeah I do. The concentrate is devilishly good to taste, but a custard flavor it ain't. You can pit it up next to
Capella French Vanilla and even their Vanilla Cupcake and you'll see that they are all one of the same -- diketone rich, buttery vanilla flavors.
Generally speaking, with an an actual real-world custard (I just made one the other day) the only thing really akin to 'buttery' is the fat from the cream and the yolk of the egg. But other than the mouth-feel
that provides, it's not all of what's responsible for the taste (as in flavor). Make a meringue and you'll get all the sweet eggy taste in the world and it is typically without yolks -- but it is light and airy, not thick and rich. So the whole custard business in eliquid is (IMO) an aspect with texture of actual custards, not the flavor. You can get the taste safely of a custard for eliquid, but not necessarily the coated mouth-feel like eating one. One way you can come close is using butyric acid (like in TFA's Vanilla Bean Gelato), but that gets to be tricky from what I have learned and it can come off as odd and nasty if used too heavily -- almost like how artificial sweeteners often stick out like a sore thumb. I digress.
p.s. I don't know of a more beautiful concentrate than FA's Meringue! And like their custard, no diketones.