Bread-Bakers v006.n082.9

i really love the pugliese bread i buy here in san francisco. it's
very crusty, and has *big* gas bubbles in it: a typical slice will
have voids from the size of a large grape on down. 

i can get crusty bread without a problem by using my clay romertopf as
a baking container, after soaking it, but i'm not sure how to get the
chewy, bubbly bread itself.  do i just need more gluten? baking
powder? essence of swiss cheese holes?

any pointers appreciated.