Acetyl Pyrazine is typically used to enhance tobacco flavors or to bring out a nutty or bready note.  However it is very strong and not very forgiving so start by adding just a drop to your mix - add too much and your juice may end up tasting like corn chips!  Recommended to start testing at 0.5% to base or less and adjust to taste.

Less baked biscuit, more fried corn fritter... I use it often under .5 (even at .5 it’s a noticeable taste) to help bakery/dessert recipes get a more deep fried edge to them, where joy I find elevates that yeasty bready taste. It’s super unforgiving though, start low, go slow.