The most important thing to establish about high-altitude baking is that it’s more of an art than a science. Or, to put it slightly differently, it’s an art informed by science. There are several reasons for this — “high-altitude” can mean many things, anywhere from 3,000 feet above sea level to 6,000 feet, or even higher. What works for a baker in one location won’t work the same for another baker elsewhere. And an adjustment that performs well in one recipe won’t necessarily...