You have read in my past baking tips posts my hints for high altitude baking. I mention the lower air pressure and low humidity levels, but I don’t dig into the explanations. For science nerds, I will delve a little deeper. For non-scientists, my explanations are short enough – grab a cookie; it will be over soon.
The lower atmospheric pressure makes a noticeable affect in baked goods. “Leavening agents such as yeast, baking powder or baking soda will have more rising power. That’s because the thinner air offers less resistance to the gases created by the leavening agent. Therefore, you should use less leavening (about 20 percent less at 5,000 feet) as your elevation increases.” If you use sea level amounts of leavening agents they will create more gasses, expanding and rising more quickly. It sounds good until you look in the oven and watch your gorgeous creation rise too fast and then fall, to ultimately suffer with the dreaded sinkhole.
Another consideration for high altitude bakers is that “above 2,500 feet, the atmosphere becomes much drier. The air has less oxygen. … Moisture quickly evaporates from everything.” The problem arises when moisture loss is not accounted for when baking at altitude, so liquids are added to recipes to counter this. Another thing to keep in mind is that all high altitude areas are not created equal. I baked in New Mexico, an area with extremely low moisture in the air. Moving to Colorado, where the air has a slightly higher moisture content, improved not only the texture of my skin but that of my baked goods, too.
A high altitude change that affects cooking more than baking is that water boils at a lower temperature. “As the altitude increases, the atmospheric pressure pushing down on water decreases, which allows the water to boil at lower temperatures. A lower boiling point means that food cooks at a lower temperature, despite the fact that the water is boiling.” When food cooks at a lower temperature in water it takes longer thus requiring lots of patience to boil potatoes. Bakers will feel it most when they are cooking above water, such as when melting delicate ingredients like chocolate.
Now that you have been armed with the scientific knowledge behind some high altitude baking alterations, you can see why changing recipes at altitude is so crucial. You can also gain insight as to why it can take six tries to perfect a high altitude recipe. At least you can enjoy eating the trial batches – we do!