Part of the problem is that I'm using a new brand and variety of yeast. In Maryland I used Fleischmann's Instant Yeast. Here the yeast I can get for a good price ($4 for two pounds) is Red Star Active Dry Yeast (RSADY). Whenever you switch yeasts, you're switching critters. Different critters behave differently.
The solution to the problem has been to increase the amount of salt in the recipe. I'm finding that with the RSADY, if I use a proportion of 3 parts yeast to 4 parts yeast (with yeast in the 2 tsp range), then I get good results for a two pound loaf. If the proportion is lower than that, the yeast gets out of control and things start falling.
A few recipes work fine without alteration, in particular my French baguette recipe and anything from Artisan Bread in Five Minutes Per Day.
We're also using all natural non-GMO unbleached unbromated flour (Wheat Montana, best flour in the world) and organic sugar. Using high quality ingredients means you'll have high quality results.