Cooking for Engineers

Eggs

• Which cooks faster, an egg in salt water or an egg in fresh water?

• Which egg cooks slower, one boiled in Colorado or one boiled at Carolina Beach, NC?

• Two eggs are placed in boiling water at sea level and cooked to the identical degree of doneness, one on a sunny and one on a stormy day. The air temperature is the same on both days. Which egg would take longer to cook?

Cooking at high altitudes

If you are a newcomer to the mountain area of Wyoming, you may wonder why your potatoes take longer to cook or why your cakes continually fall. Recipes from low altitudes usually need to be adjusted at altitudes above 3,000 feet (even Boone, NC is at 3266 ft). These adjustments are made in time, temperature and/or ingredients.

Here’s Why: High altitude means lower air

pressure, which decreases water's boiling temperature from 212oF at sea level to 203oF at 5,000 feet and to just 199oF at 7,200 feet.

Higher altitude – Lower pressure – Lower boiling point

Lower altitude – Higher pressure – Higher boiling point

So what?

This variation (lower boiling point) affects cooking of vegetables, eggs, candies, and internal structure of baked products because water and liquids evaporate faster and leavening gases in breads and cakes expand more.

So what?

If water boils at a lower temperature, then foods cooked in water or steam (potatoes, boiled eggs, chili) take longer to cook. In general, cooking time must be increased from 4-11% per 1,000 feet.

Under Pressure

A pressure cooker is great for cooking meats and vegetables which require long cooking at high altitudes. By increasing pressure, the temperature at which water boils is raised, and food cooks more quickly.

Regarding beans… When making bean soup, the starch

inside the cells swells and softens, so the beans will be tender. In the presence of acids, starch within cells can't swell, so the cells don't ever break down. So don't add acidic ingredients, such as tomato sauce, wine, lemon juice, or vinegar, until the beans are already tender.

You scream, I scream.. Which melts faster, ice cream or

sherbet?

Check out… www.cookingforengineers.com http://www.exploratorium.edu/cooking/ http://www.ochef.com/Science.htm