I use lemon flavoring when painting with gel, paste and luster dust colors – it works very well! I’ve also heard clear vanilla extract works well.

I think any extract would work, but I’m pretty sure they all contain alcohol as well. If it makes you feel better, the alcohol evaporates. A higher grain alcohol like Everclear evaporates even more quickly but you have to work fast. I don’t think there’s another option besides water and it usually leaves sticky spots.

You should take into account, as Kendra already stated, alcohol evaporates so it shouldn’t be a problem.

To better understand this, simply place a few drops of vanilla extract on a plate & walk away for an hour. When you go back to the plate, you’ll find the liquid has completely evaporated and you’re left a shiny “film” on the plate.

I often paint with straight color and then the white color mixed to give me the shade I need. BUT as they said alcohol evaporates. I like lemon extract best, it seems to flow better. I also took a painting demo with Ruth Rickey, she uses vegetable oil in powdered colors to do some of her painting.