Whip It Up!

Do you like lemon meringue pie? Did you know that the white meringue topping is made from egg whites? Making a meringue is an amazing trick. You start with a small amount of a clear, yellow liquid, and end up with huge mounds of fluffy white foam. This happens partly because of denaturation. The protein knots we talked about before can't withstand the beating, and they fall apart. But the whipping process also mixes a lot of air into the egg whites.

If you've never seen the changes egg whites undergo, it's a cool experiment to try. Take two eggs from the refrigerator, and separate the whites from the yolks while the eggs are cold (ask an adult for help). Make sure that there is absolutely no dark-yellow yolk mixed in with the whites. Then let the egg whites stand on the counter for about 30 minutes to warm up a little. Pour them into a large bowl made of glass, ceramic, copper, or stainless steel that has been carefully cleaned. Using either a hand whisk or a mixer (which is much easier), start beating the egg whites. Take a look at them every few minutes to observe what's happening.

First you'll notice that the egg whites form bubbles, although they're still yellow at this point. Then you'll notice that the liquid turns white, but is still thin and bubbly. Pretty soon, however, you'll notice that the egg whites become stiffer. If you lift the beaters out of the beaten egg whites, they form little peaks that bend over (this is called the soft-peak stage). But keep going! Eventually, you'll get stiff, shiny peaks that look like little snow-covered mountains (not surprisingly, this is known as the stiff-peak stage). At this point, you can even turn the bowl over, and the beaten egg whites won't come out. It's a pretty amazing transformation!

If you like to cook, you can sweeten the beaten egg whites with sugar, and bake them to make a kind of cookie called a meringue. You can even flavor the egg whites with things like chocolate or coconut. Do a Google search for a recipe!