Find Your Precise Altitude

• If you are baking brownies above sea level but below 3,000 feet, you do not need to adjust the volume of ingredients in your brownie batter. Brownie bars are uncharacteristically stable compared to more delicate baked items that must rise to achieve their light, fluffy textures, such as cakes, yeast breads and muffins. Even at an altitude between 3,000 and 7,000 feet, brownie batter may only need minor adjustments. Over 7,000 feet, however, additional liquids and flour are helpful.

How Elevation Changes Baking

• Air pressure and atmospheric moisture have significant effects on the chemical processes that occur in baked foods. Lower air pressure at high altitudes makes it easier for leavened batters to rise. The boiling point lowers as elevation increases, which allows moisture to cook out of food more rapidly. These environmental changes ultimately weaken the integrity of baked goods, requiring you to compensate by adding extra flour to their batter. You may only need to increase the baking temperature by 15 to 25 degrees Fahrenheit to achieve the proper texture and consistency, especially at lower altitudes.

Increase Moisture with Water or Eggs

• Because moisture cooks out of brownies more rapidly at higher elevations, you must add extra liquid to brownie batter to prevent the bars from being dry. The best ingredients for increasing moisture in brownie batter are water and egg whites. Most of the water cooks out of the brownies, leaving the rich chocolate flavor unaltered. Egg whites, on the other hand, increase the batter’s volume of moisture as well as protein. The extra protein helps the bars set more effectively. Between 3,000 and 7,000 feet, 1 to 2 tablespoons of water or one extra egg white should be sufficient. You may need as many as 4 tablespoons of water or two egg whites if your altitude is above 7,000 feet.

Increase Stability with Flour

• Brownies don’t contain a lot of flour in the first place, so you shouldn’t adjust the amount dramatically at higher elevations. Adding too much flour makes the bars dry, tough and crumbly. Start by baking a batch without additional flour to see whether alterations to the baking temperature or liquid ingredients yield the desired product. Brownies that don’t set properly resemble thick pudding more than dense fudgy bars, and they benefit from extra flour to achieve greater stability. Increase the amount of flour by 1 tablespoon if you are between 3,000 and 5,000 feet. Add 2 tablespoons of flour at elevations between 5,000 and 7,000 feet. At an altitude between 7,000 and 10,000 feet, add 3 tablespoons of flour. Above 10,000 feet, you may need 4 tablespoons.