Tuesday, April 20, 2010

Can You Boil Water?

Mad Science

Before you drag out your canning equipment for the new season, it's a good idea to review some basic information.

Can you boil water?

Water boils at 212 degrees Fahrenheit. Sometimes. Actually, water boils at 212 degrees Fahrenheit at sea level. Here in the western Rocky Mountains, sea level is a long, long way down there. So we must make adjustments in our cooking, if we wish to obtain optimal results. Here, more than anywhere else, good cooking is an art that requires a light touch, a gentle hand, and hard-earned knowledge. So even if you live at a lower elevation, those camping trips to the mountains can result in raw boiled potatoes and tepid hot chocolate, if you don’t take steps to correct for the change in altitude.

Physics

The reason for this is simple physics: As elevation increases, the boiling point of water decreases. At 4,000 feet elevation, water boils at 204 degrees; at 8,000 feet, the boiling point is 197 degrees. The lowered boiling point is 1.9 degrees for each 1,000 feet increase in altitude. This means you must cook your food longer, once it begins to boil, to get it done. In baked goods, decreased pressure causes leavening gases to expand more and moisture to evaporate faster, and because high altitude areas are usually drier than lower elevations, flour may be drier and doughs may require more liquid to reach the proper consistency.

This is important for the home food preserver. If you are using the boiling water bath method, additional processing time is required. If processing time is 20 minutes or less, add 1 minute for every 1,000 feet of elevation above sea level. If processing time is over 20 minutes, add 2 minutes for every 1,000 feet of elevation. If using a pressure canner, the processing time will not change, but the pressure needs to increase 1 pound for every 2,000 feet of elevation.

To find your elevation, enter the name of your town or locality into this website: www.topozone.com/findplace. You can also put a pan of water on the stove to boil. Suspend a cooking thermometer in the water, being careful to keep the thermometer from touching the pan sides or bottom. Leave the thermometer in the water for a few minutes after the water starts to boil, to allow the thermometer to reach its maximum temperature.

Mountain Baking Mysteries

Do your cakes tend to fall? Do your brownies stick to the pan? Altitude, not attitude, is the culprit. Most recipes for baked products are geared for sea level bakers. Always grease your baking pans thoroughly, as cakes and breads tend to stick more when they are baked at high altitudes. Using a larger size pan can also help. Above 3,000 feet, decreased atmospheric pressure may cause a cake to rise too quickly, causing its cell structure to overexpand. You want to raise the oven temperature 25 degrees, so the product will bake faster and set the cell structure, so the cake will not fall. Many mixes that require adjustment for high altitudes have specific directions right on the package. Be sure to look for them.

Angel food and sponge cakes present special high altitude problems. The leavening gas for these cakes is largely air. If you beat too much air into the egg whites, the air cells overexpand and collapse, poor dears. Aim for a gentle peak that falls over gracefully, not one that’s stiff and dry. Using less sugar, more flour, and a higher baking temperature also helps strengthen the cell structure of foam-type cakes.

Pound cakes and other rich cakes benefit from reduced amounts of fat.

Yeast bread dough benefits from higher baking temperatures, more liquid, less yeast, and more and shorter rising periods. The dough rises more rapidly and can over-rise easily, so let dough rise for a shorter time. Because flour dries out more quickly, use the minimum amount called for in a recipe, or use 1/4 to 1/2 cup less than the total amount.

Fancy breads contain more sugar, which makes them brown too fast at high temperatures, so they should be baked at 375 degrees.

Boiled candy and cooked frostings (sugar mixtures) become concentrated more rapidly because of the faster evaporation of water. Watch them closely to prevent scorching. Reduce recipe temperature by 2°F for every 1000 feet of elevation.

Cookie recipes often can be improved by a slight increase in baking temperature, a slight decrease in baking powder or soda, fat, and sugar, and/or a slight increase in liquid ingredients and flour. These changes increase the strength of the batter and improve its ability to retain the steam long enough for a crust to form. Many cookie recipes contain a higher proportion of sugar and fat than necessary, even at low altitudes. For more nutritious cookies with fewer calories, up to one-fourth of the sugar called for often can be replaced with nonfat dry milk powder without loss in product quality.

Quick breads vary from muffin-like to cake-like in cell structure. The cell structure of biscuits and muffins or muffin-type quick breads is firm enough to withstand the increased internal pressure at high altitudes quite well without adjustment. However, a bitter or alkaline flavor may result from inadequate neutralization of baking soda or powder. In such cases, a slight decrease in the baking soda or baking powder usually improves results.

Quick breads with a cake-like texture are more delicately balanced and usually benefit from adjustments for altitude. Trouble signs include: a porous, sugary crust; a coarse, gummy, or oily texture; and a low volume in proportion to weight. Try a slight reduction in the proportion of leavening agents, sugar, and fat, and/or a slight increase in the proportion of flour, eggs, and liquid ingredients. Appropriate selection of pan size and baking temperature also are important.

Cooking is definitely an art, but it’s an art that benefits from knowing a bit about chemistry and physics, as well. The Rocky Mountain Cook knows, “It’s not done when the timer goes off. It’s done when it’s done.”

Sources:
www.gofallon.com http://www.bettycrocker.com/baking/basics/high_altitude_baking.aspx
http://extension.usu.edu/files/publications/highalt.pdf

2 comments:

  1. That is really interesting. I did not even think of this before. At different levels, the water will boil at different temperatures. Thanks for the great information. Keep up the grood work with your articles and please stop by my health blog sometime. The web address is http://healthy-nutrition-facts.blogspot.com/.

    ReplyDelete

Blog Archive

About Me

My Photo
~ I'm the author of Headwind: The Intrepid Adventures of OSS Agent Katrin Nissen. If you're a WWII buff, you'll like it here!