>....Store-bought milk, already having been cooked to death in the
>pasteurization process, has lost those enzymes.
most store-bought milk is pasteurized but not ultra-pasteurized so
for best results, i.e. highest volume of the crumb it's best to use
dry milk or scald the milk. you could do a side-by-side test to
convince yourself but cook's illustrated did this a few years ago and
photographed these results. they recommended scalding and removing
the skin that forms on the surface.
re pasta rollers, i was devoted to my atlas hand crank machine but
since kitchen aid came out with the pasta roller attachment i have
retired the hand crank machine.