You don't need to be a physics major to bake a cake. But if you're living in Utah, it would help you understand why your cakes fall, your candy goes hard and your home-canning takes longer to process.
That's because most cookbooks are written for sea level — the elevation of Los Angeles and New York City. The Wasatch Front is 4,200 to 4,600 feet above sea level — higher in mountainous areas like Park City. A higher altitude means lower atmospheric pressure, and that can make a difference in baked goods, candies, home canning and other cooking, said Pauline Ingolls Williams, a home economist with Utah State University Extension in Salt Lake County.
"Bread done in bread machines almost always caves in on the top here," said Williams.
But most cookbooks don't offer alternative directions for higher elevations, so unsuspecting cooks faithfully follow a recipe only to have poor results.
The reason? Boyle's Law of Physics, said Williams, which says "the more pressure, the smaller the volume. The less pressure, the larger the volume. And, there is less pressure as altitude increases."
So, air bubbles in cake batter and bread dough expand more at higher altitudes — there's less air pressure pushing down on the bubbles. Also, the boiling point is lower, said Williams.
Even if you don't totally understand why, it pays to know how to alter your recipes for better results.
CANDY: Candies finish cooking at a lower temperature. Liquid boils at a lower temperature —about 2 degrees for every 1,000 foot difference from sea level — because there's not as much air pressure to inhibit the boiling action. (At sea level, water boils at 212 degrees. At 4,000 feet, water boils at 202 to 204 degrees.) Your cookbook says to take the fudge off the stove when it gets to 238 degrees, or a "soft-ball" stage. But the candy syrup boils and the liquid evaporates and gets to "soft-ball" at around 230 degrees. If you wait until your thermometer says 238, the fudge will be too firm.
"It's a critical difference," said Ruth Kendrick of South Ogden, author of "Candymaking." The book's recipes are written for sea level, but at the beginning she explains altitude adjustments. (Many people apparently skip that information, because she gets calls from frustrated cooks when the recipes don't turn out.)
She and Williams both recommend calibrating your candy thermometer. Put your thermometer in boiling water, and subtract the thermometer's temperature from 212 degrees (the sea level boiling point). Whenever you make candy, subtract that number from the temperature given in the recipe. If your thermometer read 204 degrees, you would subtract that from 212 and get 8. From then on, always subtract 8 from the temperature given in any candy recipes.
The calibration helps, said Kendrick, because many thermometers vary by one or two degrees.
"Most recipes have that much of a cushion, but when you're a beginner, you need every advantage you can get."
Another tip: get a "decent-quality" thermometer so it's accurate, and ignore the hard-ball, soft-ball and other markings on it, because that's for sea level.
Kendrick said thermometers are more reliable than putting a few drops of syrup in cold water and then trying to roll it into a ball. (If the ball is soft, it's called "soft-ball" stage. At around 290 degrees, the syrup cracks and is at the "soft-crack" stage).
If your candy is undercooked, you can usually put it back on the stove and cook it longer. But if it's overcooked, it's harder to save.
"Don't panic and yank it off the heat and pour it out quick," she said. "Instead, add a little hot water, which will put the moisture back into the solution, and the temperature will drop. Don't add cold water, or it will just sizzle."
Kendrick's favorite saying is, "There are no failures, just re-name it. Runny fudge can be 'hot fudge ice cream topping,' and fudge that's overcooked is 'Fudge Lumps.' Let people think that's what you intended to do."
HOME CANNING: Since water boils at a lower temperature at higher elevations, "you need to boil the food for a longer period of time to kill the bacteria," said Williams. Add 10 minutes to water-bath processing times. Instead of processing peaches for the required 30 minutes, they will need 40 minutes at this altitude. For pressure cookers, add one-half pound of pressure for every 1,000 feet above sea level.
BOILING: Cooking anything that is boiled or simmered — stews, pasta, beans — will usually take longer than recipe directions say.
"There may be excess evaporation, so you may need to add extra liquid," Williams advised. "I would go between one and three tablespoons per cup of liquid called for in the recipe."
BAKED GOODS: In baking, soda or yeast produce carbon dioxide, creating bubbles that cause your cakes or breads to rise. If the air pressure is reduced, the carbon dioxide molecules expand and rise more, so the cake might flow out of the pan. If there's not enough structure in the batter to hold all these air bubbles, the volume collapses and the cake falls.
When Raymond Lammers applied for a job as pastry chef at Stein Eriksen Lodge a few months ago, he didn't realize the resort's 8,200-foot altitude might affect his baking. He previously worked at sea on a cruise line and in Amsterdam, which is below sea level.
"It's funny, because I made a souffle without even thinking, and it still came out very nice," he said. "I think it depends on the recipe you're using. With souffles, you have to watch carefully that you don't whip them too hard. I've noticed that the lack of humidity here affects the recipes, too. And all the pastries proof (rise) a little faster than normally. Instead of 50 minutes, it takes only 40 minutes."
Lammers' advice: "If you want to do something special for Christmas, try it out before that to make sure it works."
Add a little more "toughening" ingredients, such as egg or flour, to give the batter more structure, said Williams. You could also reduce the amount of sugar by 1 to 2 tablespoons, because sugar tenderizes the batter. Or reduce the baking powder by 1/8 to 1/4 teaspoon. Increasing the baking temperature by 25 degrees helps set the crust faster so the bread or cake doesn't over-rise during the first 10 to 15 minutes of baking. (Decrease the baking time slightly.)
"Try one thing at a time, and see how it turns out," said Williams. "If you do all three things at once, you won't know what worked and what didn't."
Boxed cake mixes usually have "high altitude" directions, which call for adding a little more flour and water and a little less oil.
If you reduce the amount of yeast in a bread recipe, you may not get as much "yeasty" flavor. Instead, let the rolls or bread rise until doubled, rather than going by prescribed time in the cookbook.
With angel and sponge cakes, the leavening is largely air from whipped eggs or egg whites. So beat the eggs only until they form a peak and fall over, not until they're stiff and dry, or the cells could collapse during baking.
At high altitudes, foods like flour are drier and will absorb more liquid, so sometimes a little more liquid is needed for a batter or dough to reach the right consistency.
FOODS WHERE THE ALTITUDE HAS NO EFFECT: Anything that's raw or roasted, or any foods that don't come to a boiling point in the cooking process.
FUDGE CAKE
4 squares unsweetened chocolate (4 ounces)
1/2 cup shortening
2 cups sifted cake flour
2 teaspoons baking powder
1 teaspoon salt
2 1/4 cups sugar
1 1/2 cups cold milk
3 eggs (refrigerator temperature)
2 teaspoons vanilla
1 cup nuts, chopped and floured (optional)
Grease and flour pans or line with waxed paper. Melt chocolate and shortening together and cool slightly. Mix and sift flour, baking powder, salt and sugar into mixer bowl. Add milk, eggs and vanilla. Beat 30 seconds on low speed, scraping frequently. Add melted and slightly cooled chocolate-shortening mixture. Beat 7 1/2 minutes on medium high speed, scraping several times. Stir in floured nuts, if used. Pour batter into pans. Bake at 350 degrees for 48 minutes for two 8-inch pans, or 30-35 minutes for 28 cupcakes.
The following recipe comes from the Colorado State University Extension and is already adjusted for 4,000 to 5,000 foot elevations:
WHITE CAKE
2 1/2 cups sifted cake flour
2 1/2 teaspoons baking powder
1/2 teaspoons salt
1 1/2 cups plus 1 tablespoon sugar
1/2 cup plus 2 tablespoons shortening (room temperature)
1 1/4 teaspoons vanilla
1 cup plus 3 tablespoons cold milk
5 egg whites (refrigerator temperature)
Grease and flour pans or line bottom of pans with waxed paper. Mix and sift flour, baking powder, salt and sugar into mixer bowl. Add shortening, vanilla, milk and egg whites. Beat 30 seconds on low speed, scraping frequently. Beat 7 1/2 minutes on high speed. Scrape twice during this beating. Pour batter into pans. Bake at 375 degrees for 30 minutes for a 9-by-13-inch cake or 25-28 minutes for 2 8-inch layers, or 23-25 minutes for 24 cupcakes.
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