At high altitude, the air density is lower than at sea level.
This causes two basic problems:
First at higher elevations, water boils at a lower temperature, thus requiring you to cook longer once you hit boiling (and the time it takes you to prepare your recipe). For example, the water's not as hot in Denver as it is in Boston, even boiling. This is the reason, when cooking in the mountains, your coffee and hot chocolate can be merely tepid, even though the water was boiling.
Second baked goods tend to rise faster, requiring a change in the proportion of ingredients used in leavened foods (such as breads and cakes). Sometimes, you may need to adjust the baking temperature in your oven as well!
However, changes in altitude do not affect oven temperatures.
Note: Since baking items often rise quicker at higher altitudes, you may want to increase the oven temperature. So, at elevations over 3500 feet, the oven temperature for batters and doughs should be 25 degrees Fahrenheit higher than the temperature used at sea level. Proofing time for yeast breads should be reduced.
As you may know air pressure at sea level is roughly 15 pounds per square inch. Since there are a few miles of air above us, lots of stuff (molecules) in the air is all pulled to the earth by gravity. For example, when you go up in the atmosphere a mile (5,280 ft.) you have much less air pressure (i.e. much less air pressing down on you). The same is true for being underwater: the closer to the surface you are, the less pressure you feel in your ears; the deeper you go, the greater the pressure. Any reaction that causes expansion (like giving off gases as part of a chemical reaction), will happen slower the closer one is to sea level, since the air pressure surrounding the reaction is greater. But as one goes up in the atmosphere, the surrounding air pressure is less. Therefore expanding processes (like rising bread) would seem to happen faster and maybe more profusely.
Boiling:
In general, then, if you are making something that needs to be boiled, the cooking process will take longer at high altitudes than at sea level. At as low as 5,000 feet (1,500 meters), the boiling point of water has changed enough to change cooking times significantly. For example, expect rice cooked at 5,000 feet (1,500 meters) to take 25-30 minutes instead of 20-25 minutes of simmering before the water is absorbed and the rice is done.
Baking:
For any baked goods that rise (yeast breads, cakes or breads made with baking powder, etc.), it is important to adjust the recipe so that the rapid rise time doesn't make the resulting bread or cake too dry.
This can be done as follows:
For Yeast Breads: Yeast breads rise more quickly at high altitudes, so be sure to watch your dough carefully and judge the rise time by the change in the dough's bulk, not by the amount of time it takes.
For Recipes Using Baking Powder:
Don't overbeat the eggs. Overbeating adds too much air to the bread or cake.
Raise the baking temperature slightly; the faster cooking time will keep the recipe from rising too much.
Decrease the amount of baking powder slightly; this also prevents the recipe from rising too much.
Always grease your baking pans thoroughly, as cakes and breads tend to stick more when they are baked at high altitudes.
Read the Directions!
When all else fails, read the directions! If you're baking something you've baked for years, take a close look to find any instructions about preparing your food at a higher elevation. Usually, there will be a note (in fine print) stating what to add or delete from the recipe to make your food come out just like you've always enjoyed it!
Baking Cakes at High Altitude
Most cake recipes for sea level need no modification up to the altitude of 3,000 feet. Above that, it is often necessary to adjust recipes slightly. Usually, a decrease in leavening or sugar (or both) and an increase in liquid are needed.
Each or all of these adjustments may be required for every recipe is different in its balance of ingredients. Only repeated experiments with each recipe can give the most successful proportions to use. Simply use the guide below to adjust your recipe as needed. Where two amounts appear in the table, the smaller adjustment should be tried first. Then if the cake still needs improvement, the larger adjustment can be used the next time.
Adjustment for 3000+ feet:
Add an additional egg to rich cakes to help keep them from falling.
Increase flour: For each cup of flour increase by 1 tblsp
Decrease fat: For each cup of fat, decrease 1 to 2 tblsp.
Reduce baking powder: For each tsp., decrease 1/8 tsp to 1/4 tsp
Reduce sugar: For each cup, decrease 0 to 1 tblsp.
Increase liquid: For each cup, add 2 to 4 tblsp.
Increasing oven temperature 15 to 25°F more will help set the batter before cells formed by leavening gases expand to much.
Here I found more information and just thought I would add to what I already have. Some of it's a repeat, but useful none the less.
Canning
Time or temperature must be increased in order to kill heat-resistant bacteria. A steam pressure canner must be used for canning meats and vegetables. Follow high altitude directions available from all County Extension Offices.
Deep-Fat-Frying
When deep-fat-frying, lower the temperature of the oil about 15 degrees here to prevent food from over-browning on the outside while being under-cooked on the inside. Baking casseroles and meats require no changes.
Cake From Scratch
Are you ready for the real challenge? A cake made from scratch! If not, continue to use box mixes and follow the high altitude suggestions. For those with sense of adventure, read on.
Above 3,000 feet in altitude the lower atmospheric pressure will affect cakes. There may be excessive rising which stretches the cell structure of the cake, making the texture coarse, or the cells can break before they set causing the cake to fall. This can usually be corrected by decreasing the amount of leavening agent and by increasing the baking temperature 15 degrees to 25 degrees. Because water in the batter evaporates quicker here, there is more of a concentration of sugar in the recipe which weakens the cell structure. Therefore we usually recommend decreasing sugar and increasing liquid. The cakes most likely to fall are those wonderful sweet, sticky, gooey rich ones. These super rich cakes may require reducing shortening by 1 or 2 tablespoons or by adding an extra egg. Some recipes will work fine without changes, others will take some experimenting. Here's a table* to give you a starting point.
Adjustment
3,000 ft.
5,000 ft.
7,000 ft.
Adjustment
|
3,000 ft.
|
5,000 ft.
|
7,000 ft.
|
Reduce baking powder, for each tsp., decrease
| 1/8 tsp.
| 1/8-1/4 tsp.
| 1/4 tsp.
|
Reduce sugar, for each cup, decrease
| 0-1 Tbsp.
| 0-2 Tbsp.
| 1-3 Tbsp.
|
Increase liquid, for each cup, add
| 1-2 Tbsp.
| 2-4 Tbsp.
| 3-4 Tbsp.
|
* Table from High Altitude Food Preparation- pamphlet 41
Angel food and sponge cakes use air for leavening. It comes from beating air into the eggs. Beat only until they form peaks that fall over - not stiff and dry, which cause the cells to collapse. Again, use less sugar and more flour and a higher baking temperature. We're often asked why we don't just add more flour and water to cake recipes like they do with box mixes. Isn't this more complicated. Have you ever tried to take some of the leavening or sugar out of a box mix? The only option on a box mix is to strengthen the cell walls by adding flour and water.
High-altitude conversion tips
To convert standard recipes into those which can be used for high-altitude baking:
Use 5% more flour - to disperse the leavening action and slow down the rapid rise of the cake.
Use 20% more water - to counterbalance the rapid evaporation of liquids at high altitudes and the extra flour added to the cake batter.
Bake about 25 degrees higher - to help "set" the cake's crust.
Reduce baking time about 20% - prevent overbaking at the higher temperature.
Fill pans 1/3 to no more than 1/2 full - to avoid batter overflow caused by rapid cake expansion.
Use cold water and large cold eggs - to give cake extra strength.
Generously grease and flour cake pans - to prevent cake from sticking.
Since high altitude cakes rise higher, remove top oven rack to prevent cake from sticking to it.
Have oven calibrated by a serviceman periodically, since some thermostats are affected by altitude.
High-altitude cookie adjustment
Only cookies with lots of chocolate, nuts or dates need adjustment: reduce baking powder/soda by 1/2.
At very high altitudes, a slight reduction of sugar may help.
This is the fun part. Since I got the information from multiple places, they all have a hint as to what is best. At best this information will help you. Trial and error may be the thing for some baking.
Thanks to the folks at the Colorado State University (Boulder), the University of Southern Colorado (Pueblo), the Colorado State County Extension Office, Safeway Stores and the USDA for there help with this section. Also, "The New High Altitude Cookbook" by Beverly M. Anderson and Donna M. Hamilton.
For more information on baking at high altitudes, ask for "High Altitude Food Preparation" Pamphlet 41 from your Colorado State County Extension Office. There is no charge. It will also list other high altitude recipe books available from Colorado State Cooperative Extension.
One of the things I enjoy with running this website. On Feb 16, 2007 I received an email that has real world adjustments.
I am located at 8000 feet above the ocean and have been baking and cooking successfully way up here for 26 years, 15 professionally.
Leavening agents, just need a smidgen of a decrease (1/8 t.) from about 400-9500 feet. Above that then yes, decrease by 1/4 t
Sugar: I have yet to decrease sugar by more than 1 T per cup, actually I just measure it to just below the cup line in the measuring device.
Liquid: from many that I have met or spoken to, those below about 4500 feet inform me that there are no true adjustments. However adding up to 4 T more of liquid without adding any extra flour could result in a soggy product. I suggest adding approx. 1-2 T per cup and a tad more above 9500 feet.
1-2 T of additional flour is a definite adjustment, especially for cookies otherwise they will become much too flat rather than nicely rounded with sustenance.
My info and knowledge is not based on scientific studies, but rather on everyday experiences in the kitchen.
I hope this info helps.
Randi Levin
The Muffin Lady Inc.
After a prayer service, the Pilgrims began building hasty shelters. However, unprepared for the starvation and sickness of a harsh New England winter, nearly half died before spring. Yet, persevering in prayer, and assisted by helpful Indians, they reaped a bountiful harvest the following summer.
Pilgrim Edward Winslow described the Pilgrims' Thanksgiving in these words:
