Several of my classmates are extraordinarily interested in molecular gastronomy. The Big Fat Duck Cookbook was brought up as an excellent cookbook for molecular gastronomists.
We made Bechemel and Veloute today. We learned that Bechemel must be strained to get rid of the specks. A watery Veloute can be fixed by adding more roux. The butter that we used was not clarified very well and had residual scum. It did not make a large difference when making an opaque sauce.