I have been experimenting with Erythritol for some time now. I had been looking for a low-carb or no-carb sweetener without any aftertaste (I find stevia has somewhat of an aftertaste) but with some of the structure of crystalized sugar. Enter Erythritol!
Erythritol is available in nature, but can be produced industrially. Often it is harvested from a fermentation process (of maize or mushrooms). The nice thing is that you end up with a sugar look-alike and feel-alike crystalline matter.
For some background on the chemical side, check this blogpost.