why does the recipe of cake call for an additional flour and water when the cake is made at high altitude? what is the physics concept behind? thanks!

Question

anonymous · Answer

Water boils at a lower temperature at higher altitudes because the atmospheric pressure is less. We can't very well lower the cooking temperature because we wouldn't be able to cook the eggs to the right temperature, which has the potential of causing salmonella. Therefore, we increase the amount of water. Let's say we have the same cooking time at higher altitudes and that that the water reaches its boiling point sooner in the cooking cycle at higher altitudes. We need to increase the amount of water because the water will be boiling for a longer time. If you've ever left a pot boiling on the stove, you'll notice that the water level drops. The same idea applies here. As the water boils, it leaves the cake as steam. During cooking, we don't want to boil off all the water as doing so will cause the cake to burn. A pressure vs. boiling point curve can be found here: http://www.engineeringtoolbox.com/boiling-point-water-d_926.html

kainui · Answer

So why the extra flour though?

anonymous · Answer

I've never seen extra flour called for. My best guess would be to maintain the proper consistency by balancing out the water. There isn't physics concepts behind it as far as I know.