Chemistry and cooking collide in a new course at Carlow




For a baker, lemon meringue pie is a tart dessert with an airy foam atop a smooth yellow filling.

For students in Carlow’s molecular gastronomy course — or maybe even Alton Brown — lemon meringue pie is a colloidal system, which involves a gas dispersed in liquid, atop a smooth yellow filling.

That’s because baking is chemistry at its core, explained Monique Hockman, the professor who created the class. 

“Cooking is pretty much an art,” she said. “But baking is a science. You truly have to measure things.” 

The perfect lemon meringue pie is no exception to the rule — measuring out the ratio of egg whites to sugar in the foamy meringue is vital in trapping gas bubbles. Similarly, yeast and flour must be proportionate to create the soft, chewy dough for sunshine sweet rolls, a play on traditional breakfast rolls that involves shredded carrots and even carrot baby food.

While baking in a chemistry lab that Ms. Hockman converted into a kitchen — complete with toaster ovens under the fume hoods — four groups of students dashed around, collecting ingredients for the recipes they’d follow in their lab. Cream of tartar, flour, two containers of raspberries, oranges, lemons, pie crusts, yeast and salt (cleverly labeled NaCl for sodium chloride) lined a table toward the back of the classroom.

Ms. Hockman, who holds a doctorate in physical chemistry from the University of Pittsburgh, said she partially modeled the class from a similar course taught at Harvard University called Science and Cooking, which has been turned into a massive open online course through EdX and adapted for a public lecture series. 

Outside the food lab where Ms. Hockman’s students create mostly traditional foods, fruit juice caviar, flavored foams, and fruit or vegetable spaghetti noodles are just a few of the wacky creations people imagine when they hear the term molecular gastronomy, she said. However, most chefs who create these visionary and experimental dishes dislike the terminology.

Local chef Kevin Sousa was the first to bring molecular gastronomy to Pittsburgh with his Alchemy menu at Bigelow Grille in the DoubleTree Hotel, Downtown. Among other items, the menu offered tiny, liquefied beads of pierogi with a shot glass of highly concentrated sauerkraut consomme.

He said that molecular gastronomy is a silly term because everything is made of molecules, and all cooking is science. He admits there is a certain specificity associated with what some call molecular gastronomy, but he just calls it modern cooking.

“There’s a slightly more scientific approach to it, like why things go together that may not have been thought of before as good pairings,” he said.

Ms. Hockman also notes that the term molecular gastronomy is merely the chemistry behind cooking, not necessarily art nouveau in food.

“The idea is to achieve the tastes but in different physical states than they normally exist,” she said. 

In a nearly three-hour class one Wednesday in March, the students tried out four recipes, which appeared drastically different at first. However, each employed a leavening agent, or a substance, which causes expansion in baking.

For Ms. Hockman, the differing culinary approaches with similar scientific functions are what constitute the term molecular gastronomy.

Two of the recipes, sunshine sweet rolls and multigrain cinnamon rolls, used yeast to help the sweet dough rise. The other two recipes, for raspberry foam and lemon meringue pie, relied on cream of tartar to puff up egg whites.

In the breads, biological leavening helps dough to rise, Ms. Hockman told the class. When activated with warm water, biological leavening agents ferment sugars and carbohydrates in flour to release carbon dioxide. Yeast is the most common biological leavening agent, although unpasteurized beer, sourdough starter, buttermilk, kefir and yogurt also use the same mechanism.

The group making cinnamon rolls split up the labor. Biology major Kayla Todd, 19, kneaded the dough. Ms. Todd, of Churchill, donned a white apron with a few squares of the periodic table that spell out Iron Chef, and mixed the dough with her hands until it resembled a ball of cookie dough.

Alternately, her classmates used mechanical leavening to make meringue and foam. In this process, meringue requires cream of tartar or potassium bitartrate — which is not a cream at all, but a fine powder.

Students use a stand mixer to whip up egg whites and cream of tartar, which stabilizes air bubbles and keeps the fluffy substance from deflating. The heat and force of the mixing causes the soft peaks to form.

In chemistry terms, the amino acid chains in the egg whites uncoil in a process called denaturation. After they uncoil, they begin to mesh back together again but with pockets of air stuck inside. Adding sugar, as the students did, keeps the gas bubbles from popping. 

At the end of class, Ms. Hockman rolled in a cart with a coffee machine and lined up the baked goods on a lab table. The room fell silent as students sampled the fruits of their labor.

Despite the chemistry and hard work, Ms. Todd was, ironically, most concerned with the icing on her cinnamon rolls, which her partner made out of powdered sugar, half-and-half and butter.

“It’s amazing. You have to taste it,” she said, adding, “I want to cook now because I hadn't done it at home before.”

Courtney Linder: clinder@post-gazette.com or 412-263-1707. Twitter: @LinderPG.





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