The Accidental Scientist: Science of Cooking
Candy Bread Eggs Pickles Meat Seasoning

Monthly Feature:
multi-tasking eggs
multi-tasking eggs

"Multi-tasking," the managerial buzzword these days, isn't a new concept if you're talking about cooking. Eggs have been multi-tasking forever. And their importance in preparing a wide spectrum of foods proves that eggs can perform any number of diverse and demanding roles. This is pretty impressive for something as compact as an egg.

Egg whites are 88 percent water. Yolks nearly 50 percent. So the task of contributing liquid to batters and doughs is an easy one for eggs. As flour absorbs liquid in baking, starch granules swell to form the framework that becomes a cake, a muffin, a cookie. Eventually moisture converts to steam, a leaven so powerful that just one part liquid explodes into 1,600 parts steam. Break into a cream puff or a popover (high ratio of eggs) and their hollow centers provide dramatic testimony to steam's immense power. On a smaller scale, the steam created from the liquid in just one or two eggs works quietly in most batters and doughs to boost rising.

The proteins in eggs also enable them to act as leavens but in a completely different manner. Proteins unwind and stretch to form the flexible, elastic film that encases air bubbles. When eggs are beaten, they can expand to a foam that's up to eight times their original volume. Beaten egg whites hold millions of tiny air bubbles, which lift angel-food and sponge cakes, meringues, and souffles. Even in batters containing baking powder, beaten eggs whites are an additional source of leavening.

Each month, we've featured a different kitchen science article by the Inquisitive Cooks, Anne Gardiner and Sue Wilson , with tips, facts, and unique ideas to give you a whole new perspective on cooking.

View other articles.

Also visit Ask the Inquisitive Cooks for a weekly kitchen science Q&A!

What happens if you leave a bottle of milk in the fridge too long, or if your yogurt sits out in the sun? You get rancid yuck, right? But somehow, if done just the right way, a similar process can result in fragrant, pungent, yummy cheese.

How can this possibly happen? View the Webcast and watch as we investigate the creamy, rich--and sometimes stinky world of cheese.

While the elastic quality of proteins is lost when eggs are cooked, the firming of proteins allows eggs to perform yet another function. As their proteins coagulate, eggs bind ingredients together. Meat loaves are less likely to crumble. Casseroles serve in tidier portions. And a crumb coating holds more tightly to a veal cutlet when its been dipped in egg before being rolled in breadcrumbs.

In creme caramel and quiche, egg proteins unwind, then bond to form a mesh that traps milk or cream in a soft gel. And in a stirred custard or creme anglaise, eggs thicken just as effectively, but at lower temperatures than flour or cornstarch.

Lecithin and the other emulsifiers in egg yolks come in handy too. Tiny droplets of fat stay suspended throughout emulsions such as mayonnaise, hollandaise, and bearnaise when coated with a thin film of yolk. Without the emulsifying properties of eggs, these special sauces wouldn't be as luxurious, nor as smooth.

It's eggs, not lemon, that add the rich yellow color to a lemon pie filling. And of course they contribute flavor to any food in which they're used.

Looking at just some of the ways we use eggs makes us think perhaps we give too little credit to their special qualities. They might not look as splashy as a frilly head of lettuce or announce their presence with a searing burn of a hot pepper. But the humble little egg is surely handy in the kitchen and confirms that in cooking, this one extraordinary character can indeed accomplish the work of many.

Anne Gardiner & Sue Wilson are the authors, with the Exploratorium, of the book The Inquisitive Cook.


  - - - Science of Cooking - - - Webcasts - - - Ask The Inquisitive Cooks - - -  


© Exploratorium | Use Policy | Privacy Policy