It depends on the bread machine as to what adjustments will work the best. In addition to cutting the yeast and increasing liquid, see if the owner’s manual for your machine has any tips and special setting options for altitude. It will likely take some experimentation, but the following suggestions are recommended for using bread machines at higher altitudes:
• Decrease yeast by ¼ to ½ teaspoon for every package (2½ tsp.) called for in the recipe. (Above 9,000 feet, decrease by ½ to ¾ tsp.)
• Add 1 to 2 tablespoons of additional liquid per cup of flour in the recipe. However, be careful not to add too much liquid. The dough must come clean from the sides during the final stages of mixing.
• An increase from 1 teaspoon to 1½ teaspoons of salt is recommended for optimal proofing (similar to amounts in commercial bread).
• Use the longer mixing cycle (i.e., sweet bread cycle) to help control overproofing by allowing the gluten to develop more fully.
• At higher elevations, it may help to add a little gluten (up to 1½ tablespoons) and lecithin (1½ teaspoons) to help stabilize the structure and make it less likely to fall.
Although not specific to bread machines, the Colorado State University Extension Resource Center has the publication "Making Yeast Breads at High Altitude" available for purchase at www.csuextstore.com/store/pc/viewCategories.asp?idCategory=76.
