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(Photo illustration by Julie Barnett)

Chemistry of cooking views cuisine at a molecular level

It's no use crying over spilled milk, sure, but a fallen cake, now that's a tragedy. There are a handful of artful diagnoses for cakes that suffer from a slump in the middle, aka "sad cake syndrome." Most likely, the baker has failed to incorporate enough air into the batter, perhaps because he or she didn't beat it long or thoroughly enough. There could be a more scientific explanation, too. In "Chemistry 101 for Pound Cakes," Chef Rick of chefrick.com advises that a new brand of sugar may let you down because not all sucrose crystals are the same. One of sugar's jobs in a cake batter (in addition to making it sweet, of course) is to gouge out tiny pockets that then fill with air. During the baking process, steam will fill those holes, producing the loft so prized by pastry chefs.

"If the crystals of `one brand` are smaller than `another`, or the edges of the crystals aren't as sharp," Chef Rick reports, "they won't cut into the butter as deeply." Small holes = sad cake.

Most of us aren't used to thinking of our food at a microscopic level, but for others it comes naturally. Trinity University Chemistry Professor Nancy Mills has been teaching at the college since 1979. She's been an avid cook and diner for even longer. "My husband says my family travels on its stomach," she laughs. Her love of cooking was fostered in her small Nebraska hometown by her father, who once brought a French woman over to cook so that "we could see what real tomato soup was like."

Although Mills spends the bulk of her day contemplating beakers, for her it's a natural transition to beaters. She'll be sharing some of her knowledge on Wednesday, February 2 as part of Trinity's Food for Thought luncheon series.

The press release for the event says that the series "offers Trinity professors the opportunity to leave the classroom," but Mills does not sound like your average shut-in. She sounds like an epicurean who is very comfortable with her food's origins. Take fish for instance. Plenty of folks who like to dine on salmon won't cook it at home because of the fishy stench that lingers long after the repast is past. Fish degrade at a lower temperature than other organisms, explains Mills. "If they didn't, the oceans would be full of dead fish." That unmistakable odor is caused by bases -- amines such as cadaverine (I trust we don't need to dig into the root of that word) -- that form as the fish begins to break down. Poach the offending pesca in lemon juice or wine and the acid will stabilize the amines. Voila, no stink.

Chemistry can also demystify some seemingly arbitrary rules that mark the line between delicacy and disaster. Meringue, the edible cloud made from egg whites and a bit of sugar, must be made in a metal bowl because plastic can absorb oils. Even a small amount of oil will prevent the egg whites from expanding to their full volume.

For the everyday cook, Mills has tips for producing the perfect hardboiled egg. Prick a small hole in the larger end of the shell. This will pierce the egg sack "for the chick that we never think about." The egg white will fill the space, and you will have perfectly ovoid hardboiled eggs, great for pickling whole, or creating a stunning batch of deviled eggs.

Mills also has a solution for that unappetizing green layer that forms around the yolk. The pea-green hue comes from the sulfur in the white, which migrates toward the center of the egg, meeting the iron in the yolk. Plunge eggs into ice-cold water as soon as they are done cooking and stop the sulfur in its tracks for sunny yellow yolks.

For Mills, solving problems and creating effects by understanding what's happening at the molecular level is "what's fun about chemistry" and cooking. She may be armed with more knowledge than the average cook, but she doesn't use special tools or utensils. "But if I could take some of the equipment from my chem lab into my kitchen, you'd have some great stuff." Her first choice for adaptive re-use would be a reflux condenser, a container for boiling liquids that has a cap that catches condensation and returns it to the pot. "You could boil stuff all day and it wouldn't go dry. I think it's an important safety feature," she chuckles.

Mills will be sharing a recipe or two with her Food for Thought audience, including a favorite, green beans flavored with rosemary. The secret she says, is using butter to extract the flavorful essential oils from the herb. Because butter and essential oils are non-polar, they're attracted to each other. Which doesn't explain our seemingly boundless attraction to the creamy fat, but that may be a mystery that's better savored than solved.

By Elaine Wolff

Nancy's green beans

Adapted from a recipe in Bon Appetit, December 1995
8 servings

2 lbs green beans, trimmed
1/4 c butter
1 T chopped fresh rosemary (or more)

Cook green beans in salted boiling water until just tender. Drain and pat dry. Set aside. Melt butter in a large skillet over medium-high heat until frothy. Stir in rosemary and sauté for 3-5 minutes. Add green beans, toss to coat, and heat until the beans are warm. You can cook the beans earlier in the day and add them to the rosemary butter just before serving. You can experiment with other fresh herbs and other vegetables, although green beans are a wonderful vehicle for many flavors.

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