There's another reason you can't make good corn tortillas at home -
you're using dried masa mix. High-end tortilla makers start with
dried whole-kernel corn. The corn is cooked in vats to make masa
which is used immediately to make tortillas. The machines in the
little mom-and-pop tortillerias work the same way. One machine the
size of a VW can process 300 lbs of corn per day.
_Translation Nation, Defining a New American Identity in the
Spanish-speaking United States_ by Hector Tobar, ISBN 1-57322-305-0,
page 160. Very interesting book.
Jeff