23 December 2012

Well Here I Am


Never in my wildest dreams would I ever think I'd be living in a square state.  Or an entire state that has less population than the previous city I lived in.  Now I've lived in some pretty different places - Akron, Ohio; Oshkosh, Wisconsin; Huntsville, Alabama, but never west of the Mississippi.  And never at altitude.  

I am currently sitting at 6,062 feet above sea level which is 5,744 feet higher than I was just a few weeks ago.  This had led to some pretty interesting discoveries.  First, running is near impossible right now - I'm talking full on huffing and puffing after a quarter-mile.  Secondly, I'm having fun learning how this huge difference in atmospheric pressure effects nearly everything in the kitchen.

The table below indicates air pressure at elevations below and above sea level:


So what does this mean?  Most recipes are written for elevations from sea level to >3,000 feet.  As you go up in elevation the absolute atmospheric pressure drops off steadily.  How does this affect cooking and baking?

1. Water boils at a lower temperature:

 Elevation    Boiling Point of H20 
Sea Level              212ºF 
 3,000 ft         206.7ºF 
 5,000 ft         203.2ºF 
 7,000 ft           199ºF 
10,000 ft         194.7ºF 

High altitudes mean reduced air pressure, meaning that water can boil at a lower temperature. The result is that it takes longer to cook and bake foods, since the lower temperature slows down the chemical and physical reactions that occur during baking and cooking.  For instance, dense cake batter or dough will take longer to bake completely, especially in the center, when baked at an altitude above sea level.

2. Moisture evaporates more quickly:

At higher altitudes, moisture evaporates faster than at lower altitudes. This means that moisture will leave your baked goods more quickly than at sea level. 
  • Reduced moisture can jeopardize the overall structure of baked goods.
  • Flavors can become weaker or less pronounced, since there are fewer moisture molecules to carry the aromas.
  • Baked goods tend to dry out, even go stale, much faster than at sea level.
3. Air bubbles expand and rise more quickly:

Low air pressure induces rapid expansion of leavening gases, which are bubbles formed from air, carbon dioxide, and water vapor that rise in products with yeast, baking soda or baking powder.
  • Cakes will rise very fast but fall even faster, resulting in a dense, flat cake.
  • Recipes calling for stiffly beaten egg whites might experience excessive expansion while baking, causing the egg whites to pop, resulting in a collapsed cake or baked good.
  • Low pressure can cause yeast bread dough to over-proof, or rise too much, resulting in warped or flat bread after baking.
Baked goods tend to act in similar ways so you can plan the proper adjustment based on the type of baked good.  There is no right way, as altitudes, environments, and oven temperatures vary.  The best way to adjust for high altitude is on a recipe by recipe basis.  All of the adjustments may be needed, or only one or two; it depends on the recipe.  Experimentation is key to finding the perfect balance, be sure to keep notes!

King Arthur Flour has an excellent altitude adjustment guide:
                         General Changes When Baking at High-Altitude
WHAT TO CHANGE
HOW TO CHANGE IT
WHY
Oven temperature
Increase 15 to 25°F; use the lower increase when making chocolate or delicate cakes.
Since leavening and evaporation proceed more quickly, the idea is to use a higher temperature to “set” the structure of baked goods before they overexpand and dry out.
Baking time
Decrease by 5-8 minutes per 30 minutes of baking time.
Baking at higher temperatures means products are done sooner.
Sugar
Decrease by 1 tablespoon per cup
Increased evaporation also increases concentration of sugar, which can weaken the structure of what you’re baking
Liquid
Increase by 1 to 2 tablespoons at 3,000 feet. Increase by 1 1/2 teaspoons for each additional 1,000 feet. You can also use extra eggs as part of this liquid, depending on the recipe.
Extra liquid keeps products from drying out at higher temperatures and evaporation rates.
Flour
At 3,500 feet, add 1 more tablespoon per recipe. For each additional 1,500 feet, add one more tablespoon.
In some recipes, a flour with a higher protein content may yield better results. Additional flour helps to strengthen the structure of baked goods. 
Leavening
When using baking powder and baking soda, the following chart can help you how to adjust amounts.  When baking a recipe that calls both baking powder and baking soda plus an acidic ingredient, like buttermilk or sour cream, try switching to all baking powder and sweet milk.
                   Adjusting chemical leavens according to altitude
BAKING POWDER 
OR BAKING SODA
3,000-5,000 FT
5,000-6,500 FT
6,500-8,000 FT
1 teaspoon
7/8
1/2
1/4
1-1/2 teaspoons
1-1/4
3/4
1/2
2 teaspoons
1-1/2
1
3/4
2-1/2 teaspoons
1-3/4
1-1/4
1
3 teaspoons
2
1-1/4
1
3-1/2 teaspoons
2-1/2
1-1/2
1
4 teaspoons
2-1/2
1-1/2
1
Cakes:  Use extra eggs to increase liquids; if only part of an egg is needed, use the whites. 
Crackers and Pie Crusts:  Won’t be dramatically affected; will usually need extra water to help the dough to form. 
Fried Doughs:  Lower the frying temperature by 3 degrees per 1,000 feet and increase cooking times. 
Quick Breads:  Use the guidelines above to make adjustments. 
Yeast Breads:  Decrease the amount of yeast in the recipe by 25% and make water/flour adjustments as necessary to get a dough with the correct texture.  Make sure your bowl has plenty of room for the dough to rise in.  Since rising times are much shorter at higher altitudes, you have a number of options to help its flavor.   
Give the dough one extra rise by punching it down twice before forming it.
  • Try covering the dough and placing it in the refrigerator for its first rise, to slow the action of the yeast give the dough more time to develop.
  • If you have sourdough starter on hand, use some of it for some of the liquid in the recipe.
  • Make a sponge by mixing the yeast, the liquid in the recipe, and 1 to 2 cups of flour. Cover and let the sponge work for a few hours in the refrigerator to develop it. 
Cookies:  Because cookies bake for a shorter amount of time than bread or cakes, and are relatively low in water and high in fat content, they’re much less susceptible to the vagaries of high-altitude baking.  The principle adjustments recommended for cookies baked at higher altitudes (generally considered to be above 3,000 feet) are to increase the water slightly, to help the dough come together, and to decrease the amount of chemical leavens (baking powder, baking soda) used.  Experienced high-altitude bakers know to bake at slightly higher temperature, with a shortened baking time.  
I hope this sheds some light on the mysteries of cooking at altitude and offers some solutions.  Stay tuned for my trials and tribulations and hopefully lots of delicious successes!

Additional resources:
King Arthur Flour: http://www.kingarthurflour.com/recipe/high-altitude-baking.html
Colorado State University Extension Resource Center:  http://www.ext.colostate.edu/pubs/pubs.html#nutr_high
Food Service Warehouse Education: http://www.foodservicewarehouse.com/education/bakery/c27622.aspx