Note: This experiment ends in faaaaiillluuuurrre. I found a great different way to make xylitol candy, though, that I'll post in a day or two.
Xylitol is a pretty fun sugar substitute. You'll find it advertised as being in a lot of gums and the like, and that's because when xylitol dissolves in your mouth, it actually makes your mouth colder. Some things like cinnamon or spicy peppers make your mouth think it's getting hotter, but they don't really; xylitol is the real thing in terms of dropping degrees.
If you'd like to get all sciencey about it, it's called the ENTHALPY CHANGE OF SOLUTION, a.k.a. heat of solution, and xylitol and erythritol are the two artificial sweeteners that are really kingpins of this cold cold movement. Don't think xylitol's some weird technical ingredient, either - you can find it right over on Amazon.
Why am I playing with xylitol? I'm attempting to make a super-cold candy for Masters of Social Gastronomy later on this month, so I was thinking it'd be a good bet.
For all the candy-making charts for sugar that exist online, though, It's impossible to find information about what happens when you heat up xylitol. Everything points to it not being a good candidate for a xylitol-only candy, but nothing can really tell me why. So let's do an experiment.
I put 2/3 cup xylitol in a pot over an induction burner, set to 140. It started melting pretty much the same way sugar does, but then it kinda stopped. The stuff on the bottom was melted, but everything above it was not. I'm guessing this is because as xylitol melts it absorbs a ton of energy. I ratcheted it up to 180F and waited some more.
[Note from weeks after I did this: This was a result of using an induction burner! I later discovered xylitol's melting point is around 95C/203F, so I'm guessing the heating unit was heating up to >200F and then coasting down to 180F, repeat repeat repeat. Cycling = not fun for science.]
Finally, it was melted. When you make candy out of sugar, you drop a bit of the melted parts into cold water to see what's going to happen when it solidifies. So, I did that. OK, it boringly melted away into the water. Now let's just hop up to 320F.
Much much later: NOTHING WORKS. IT NEVER CHANGES, FOLKS. NEVER CHANGES.
I am giving up!