High Altitude Bread Baking
Irwin Franzel came up with the solution when he vacationed in Denver several years ago. He was kind enough to allow us to reprint his advice in our book THE BREAD MACHINE MAGIC BOOK OF HELPFUL HINTS. So to quote Irwin and ourselves: At higher elevations, the dough "overproofs." Due to the lower barometric pressure at high altitudes, the carbon dioxide gas bubbles created by the yeast expand more rapidly. Therefore, the bread rises too high, the gluten loses its strength, and the bread collapses during baking. Try the following combination of suggestions: Reduce the amount of yeast by about 1/3. This will create less carbon dioxide and the bread will not rise as quickly.
Add from 1/2 to 1 T gluten per cup of flour. Increasing the gluten will give added strength to your bread.
Watch your dough as it mixes. You may need to add at least 1 to 3 T more liquid since flour stored at high altitudes tends to be drier.
Two other options: Because of the rapid-rising nature of high-altitude breads, try baking them on the Rapid Bake cycle of your machine to reduce the rising time. Or, if your machine has a programmable mode, watch the loaf as it rises; when it nears the top of the bread pan, switch to the Bake cycle manually.