Effects of Pressure on Bread

Temperature is not the only condition that affects bread. The pressure of the surroundings also determines conditions of making bread dough. In the mile-high city of Denver, the atmospheric pressure is much lower than at sea level. Therefore, the carbon dioxide gas produced in the fermentation process encounters less resistance from the surroundings as it is expanding. Due to this fact, the same amount of carbon dioxide will expand with greater force and produce gas pockets in the dough quicker. Consequently, unless less yeast is used in the recipe, the baked bread will have a much rougher texture than the same recipe made at sea level.

This is similar to the fact that an egg takes longer to cook high above sea level. As was stated before, the atmospheric pressure is lower at high elevations. Water boils at a lower temperature when the atmospheric pressure is less. Water, like any substance, boils when its vapor pressure equals the surrounding pressure. The vapor pressure of any substance increases with an increase in temperature. Since the water is boiling at a lower temperature at a higher elevation, the egg, like everything else, takes longer to cook at a lower temperature.

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This project was funded in part by the National Science Foundation and is advised by Dr. Masel and Dr. Blowers at the University of Illinois.

2007 Arizona Board of Regents for The University of Arizona