Friday, December 16, 2011

What Happens When You Cook At High Altitudes







High altitude has a profound effect on baking.


Atmospheric pressure at high altitudes is much lower than it is at sea level, and this lower air pressure affects cooking primarily due to the effect of lower air pressures upon water. According to the U.S. Department of Agriculture Food Safety and Inspection Service, most cookbooks define high altitude as any elevation over 3,000 feet above sea level. Lower atmospheric pressure translates directly into lower humidity levels, causing moisture to evaporate faster from foods with high water content. Lower air pressure also allows leavening agents to act more easily, causing dough to rise more quickly than it does at sea level.


The Boiling Temperature of Water


Water boils at lower temperature at high altitudes than it does at sea level


The boiling temperature of water decreases by nearly 2 degrees Fahrenheit for every 1,000 feet of elevation above sea level, according to Colorado State University professor Pat Kendall. Water will not increase in temperature beyond the boiling point unless a pressure cooker is used. Turning up the heat does not make boiling water hotter, it just makes the water evaporate faster. Pasta, rice or any other boiled foods will cook slower at high elevations than they do at sea level. If a pressure cooker is used, higher weight settings will have to be used in order to maintain pressure, due to the larger pressure differential at high altitude. Any foods boiled at high altitudes will require more time to cook than they do at sea level.


Lower Atmospheric Pressure.


Lower air pressure at high altitudes means less resistance for leavening agents to overcome, causing breads and cakes to rise faster. The easiest way to counter this effect is to adjust the amounts of various ingredients in recipes designed for sea level cooking; use less baking powder or shortening, or increase the amount of eggs used. Another means of countering the effects of lower air pressure is to raise the baking temperature, allowing the cell structure of cakes to set before they over-rise and fall. Bread dough will rise faster at high altitude than it will at sea level. Rising time is a critical factor in bread baking, and shorter rise times will make for less flavorful bread. An effective countermeasure is to punch or knead the bread dough twice before baking, giving the bread plenty of time do develop flavor without over-rising.


Lower Humidity at High Altitudes


The lower humidity levels in high altitude air cause water to evaporate faster; meat dries out quicker during cooking and sauces reduce faster than at sea level. Moist-heat cooking methods like braising take longer due to lower liquid temperature, and baked or roasted foods often dry out before they are fully cooked. The most effective way to counter the lower humidity levels found at high altitudes is to increase the amount of liquids used and to cover roasted or baked food with foil or baking bags while it is in the oven.


Food Temperature


Due to the effects of high altitude on the boiling temperature of water and the increased rate of water evaporation at higher elevation, a cooking thermometer becomes an essential tool for proper food safety. Meats will dry out and brown much faster at high altitude, giving them the appearance of being done when they are still undercooked. Home-canning of food requires longer boiling times at high altitude than it does at sea level, as with any boiled food prepared at high elevation. Liberal use of a cooking thermometer will help insure that safe cooking temperatures are reached.

Tags: high altitude, does level, evaporate faster, high altitudes, humidity levels