When you wish to take some good chocolate, make it the evening before in an earthenware coffeepot and leave it. The night rest concentrates it and gives it a smoothness that improves it.This sounds a bit strange. I would expect some evaporation to thicken the chocolate up a bit, so the concentration makes sense, although I would guess it wouldn't be a big difference. As far as the smoothness goes, I would guess that melted chocolate in milk cannot get any more smooth. But, in my quest for the best hot chocolate, I decided to do a little experiment. I made hot chocolate, left it in the fridge for two days, then I made an identical hot chocolate. After heating up the first chocolate, I tasted them side by side. It was undeniable, the first really was noticeably thicker and smoother, a substantially better hot chocolate.
I wonder if the same effect could be accomplished by gently heating the chocolate for longer, so that more evaporation takes place. As researchers say in each paper "More research is needed". Does anyone want to give me grant money?