I am getting ready to play with this method, but I heard a couple of weeks ago from Duff on Ace of Cakes that he mixes the dust with Vodka. He said it would dry quickly. I think you are supposed to add just enough to the dust to make it fluid enough to brush it on. That part I need to play with, I hope it works well. I am planning on using it on an upcoming 50th anniversary cake.
Most people I have heard talk about this say to use vodka or everclear because they are tasteless (?). You can also use lemon extract. The alcohol works better than water because it dries (evaporates) more quickly.
That is how I have heard of it done before. I am planning on trying to put a small amount in a little squirt bottle to see if I can make it have a thinning effect. I don't really want the full brushed look for what I am going for, but I also don't want to spend the money on airbrushing supplies. But, yes, the vodka and the brush is how I have seen it done before.
Using a clear alcohol or extract works best. People use clear vanilla, lemon extract, vodka, gin or everclear. Some have even mentioned mint extract. I like using vodka because it leave no taste and dries quickly--I would use everclear which is a grain alcohol, but I cannot get it in my area. I also put a little bit of dust in a tiny bowl and add the vodka with a medicine dropper--that way I have control over how much I add. Testing it on a piece of fondant is a good idea--I do that when I want to play around with color combinations.
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