Philip, You might try getting an instant-read thermometer and checking the
internal temperature using your normal baking method. If it is in the low
end of the fully baked range, say 195 F (measured when you are ready to
remove the bread from the oven, not just opening the door), you might try
bring the temperature to 200 or even 205 F. Reinhart's BBA suggests 205 F
for ciabatta which is probably similar is texture and shape to your
bread. The higher internal temperature should drive more moisture out of
the bread. There is a tradeoff here; getting the crust to crisp might
alter the texture of the crumb.
BTW, I freeze nearly all my breads since one batch of most recipes is too
much for just the two of us. Freezing crisps most crusts. I double wrap
the breads with the inner wrap being aluminum foil so that I can just toss
the loaf (or slices), still in the foil, into a toaster oven. Once the
bread is thawed, I unwrap the bread and let it rest uncovered in the warm
toaster. The crust will be much crisper than fresh. Overall, it is not a
good as freshly baked bread but still a lot better than any bread you can
buy wrapped in plastic in the supermarket.
Werner