"Frosting" is a term used to describe the layer of "crystals" that forms on the surface of natural wax, such as soy

This is a natural effect that occurs when the wax is heated up, then cools, returning to its natural state.

Frosting is not a reflection of the quality of the candle, or shouldn't be seen as a negative feature!  Overall, the occurrence of frosting is actually a GOOD INDICATION that the wax you're burning, is ALL NATURAL! So, cheers, to non-toxic fumes & sustainable living