Reply to "Royal Icing Not Drying"

I have this same problem. I'm pretty sure it has something to do with the ingredients in each individual extract. I've never used almond emulsion but I use pure almond extract and it dries nicer than any other flavor I've tried. I like to use raspberry extract because it tastes absolutely amazing but it won't dry without a dehydrator and even then it's a crap shoot sometimes. I was thinking about posting a similar question earlier but I got distracted by searching for airbrush stuff . It seems like extracts that have propylene glycol have drying issues. That's what I've noticed at least. Whatever that ingredient is it seems to possibly cause the royal icing to separate faster and not dry properly. Anybody else have any ideas? I'd love to hear some theories on this.