@minas6907 Maybe I didn't make the post clear enough:
The fondant is FINE after I make it; it is smooth as silk and perfect as I understand what fondant is supposed to be.
The problem is when I melt it and add butter and flavorings to make centers for bon-bons. It's fine, nice and smooth, about 75% of the time. The remaining times it has a very tongue-feelable graininess.
Following advice I saw in a video I was heating to 140, but Greweling's advice is hotter, 160, so I started taking it up that high. Two batches done that way were fine, but the most recent batch--a 160 batch--was back to having that grainy feel.
And that's the twist: the fondant is FINE until I melt and mix, and it doesn't always set grainy. But I don't know what parameter is causing it to do that.