Presentation on theme: "Extension.usu.edu High Altitude Cooking 2011 FACS Nutrition & Food Science Conference Karin Allen, PhD USU Extension Food Quality & Entrepreneurship Specialist."— Presentation transcript:
extension.usu.edu High Altitude Cooking 2011 FACS Nutrition & Food Science Conference Karin Allen, PhD USU Extension Food Quality & Entrepreneurship Specialist
Why Elevation Matters There is less atmosphere above us at high altitudes – this results in less pressure pushing back down Figure 6.6 in The Atmosphere, 8 th edition, Lutggens and Tarbuck, 8 th edition, 2001.
extension.usu.edu Two main Consequences 1.Lower atmospheric pressure means water boils at a lower temperature This affects all types of cooking 2.Lower atmospheric pressure means gasses can over-expand This primarily affects baked goods
extension.usu.edu Lowered Boiling Point This video from Edwards Vacuum demonstrates that water can be made to boil, and even freeze, just by lowering the atmospheric pressure: http://www.youtube.com/user/edwardsvacuum#p/u/17/pOYgdQp4euc
extension.usu.edu Lowered Boiling Point Temp of boiling water drops ~1°F every 500 ft More water is lost to evaporation during cooking – foods dry out more easily Food is at a lower temperature, so it must be cooked longer Exception – microwaved foods cook more quickly!
extension.usu.edu Adjustments for Baking at 5000 ft Increase oven temperature 15-25°F Proteins and starches will set sooner, so the cake does not dry out or collapse Decrease sugar by 2-3 Tbsp per cup With less sugar present, proteins set at a lower temperature Increase liquid by 2-3 Tbsp per cup This keeps many types of cakes moister
extension.usu.edu Over-Expansion of Gasses These videos from Edwards Vacuum demonstrate how over-expanding gasses can destroy the structure of food foams and cause them to collapse: http://www.youtube.com/user/edwardsvacuum#p/u/3/nDMySLjeyL0 http://www.youtube.com/user/edwardsvacuum#p/u/2/coi5JVAId7Y
Over-Expansion of Gasses At sea level, higher air pressure prevents bubbles from over- expanding At higher altitudes, there is less outside pressure to control expansion
extension.usu.edu Adjustments for Baking at 5000 ft Increase flour by 1-2 Tbsp per cup More gluten can be developed, so the films around the bubbles are stronger Decrease leavening by ¼ tsp per tsp Less gas is generated so less expansion occurs Decrease fat by 1-2 Tbsp per cup Less air is incorporated during creaming & more gluten is developed during mixing
extension.usu.edu Additional Resources USU Extension County Elevation Guide USDA Fact Sheet http://www.fsis.usda.gov/factsheets/high_altitude_cooking_and_food_safety/index.asp Boiling point/elevation table http://www.engineeringtoolbox.com/boiling-point-water-d_926.html Boiling point calculator http://www.csgnetwork.com/h2oboilcalc.html Additional Edwards Vacuum videos http://www.youtube.com/user/EdwardsVacuum