Does the type of sugar make a difference when making chocolate? I was checking some sites on how to make chocolate myself.
I should start with mixing cocoa butter, cocoa powder and sugar (and milk powder if I would make milk chocolate). Most sites mention "sugar". I'm assuming those are talking about granulated sugar. I've also found a few sites that call for powdered sugar.

Since granulated sugar has larger particles, I guess it takes longer to be completely melted. But I believe it would happen (so the chocolate would not turn out grainy).
Powdered sugar has smaller particles, so it should be absorbed rather quickly. However, there is also some starch added. Would this have an effect on the chocolate? Or is the amount too small for that?

(After the mixing it together, I should melt and temper it, with adding some existing chocolate.)

So, does the type of sugar make a difference in the taste or structure of my self-made chocolate?
Speaking from making fudge, I have gotten the most consistent results using superfine / castor sugar. 


I haven't noticed starch related issues from powdered sugar, but your mileage may vary; the problem I have had with it is due to clumping in spite of the starch (particularly in a frosting recently). 
I have used granulated sugar to make fudge and it is grainy. I melted most of it, but got sick of stirring it as it got crazy thick. I suppose it's possible to get it to the point of a completely dissolved syrup, but that would take longer than it is worth since you are likely going to run the risk of scorching.


Relative to the taste and structure, you won't get anything special from the caster sugar. However, you will get a more predictable product, and less hassle waiting for it to dissolve. You will also avoid texture problems and reduce the risks brought on by extended time in the pot (i.e. too much heat, likelier to accumulate moisture randomly).