From five-star restaurants to grandma’s homemade cookies, cooking is an art that has changed the way we taste food. But have you never wondered how cooking works? How on earth did people discover how to do dipping dots or jell-o?
Patrick Charbonneau is an Associate Professor of Chemistry here at Duke and gave a delicious talk on the science of cooking (with samples!) Last Friday.
About 10,000 years ago, people discovered that fermentation can convert milk into yogurt, which is more portable, lasts longer, and is easier to digest. In the 1600s, a new cooking device called a “bone digester” made it possible to cook faster while improving the taste at the same time. When the 19th century came, a scientist named Eben Horsford discovered that adding an acid with sodium bicarbonate to make baking soda. Scientific and culinary minds soon began to work together, and new creations were being created in the culinary world. As you can see, many of the basic cooking techniques and ingredients we use today are the product of scientific discovery.
A big part of cooking is controlling the transformation of matter, or “a phase change”. Professor Charbonneau presented a very cool example showing how controlling this phase shift can affect your eating experience. He made the same toffee recipe twice, but changed it slightly as the melted toffee mixture cooled. You’re putting one version in the freezer right now; wipe the other while it cools. The wiped version is crumbly and sweeter; the other turns into a tough, shiny caramel. The audience got samples and I could easily see how different each version looked and tasted.
Charbonneau explained that while both toffees have the same ingredients, most people prefer the crumbly one because it appears sweeter (I agreed). This is because the tougher one takes longer to dissolve on your taste buds, causing your brain to register them as less sweet.
I was fascinated to learn that a lot of food is mostly just water. It’s strange to think that a solid could be made of water, but some foods are 99% water and still have elasticity! We have polymers – long repeating patterns of atoms in a chain – thank you for that. In fact, you can turn almost any liquid into a gel. Polymers take up little space, but play an important role not only in food, but also in other everyday objects such as contact lenses.
Charbonneau also showed us a seemingly magical way of baking cakes. He took about half a cup of Dixie cake batter, inserted a whipped siphon loaded with nitrous oxide for a second, then tossed it in the microwave for thirty seconds. Boom, just like cake. A cup of damn good fluffy chocolate cake came out. The gas bubbles in the butter and egg dough expand when heated, causing the dough to gel and form a solid network.
Professor Charbonneau does things like that in his class here at Duke, The Chemistry and Physics of Cooking, all the time.
There has been an increase in science cooking classes over the past decade. The experiments you can do in a kitchen lab are so cool and can make science attractive to those who would normally shy away from it.
Another cool thing I learned at the stations outside of Charbonneau’s lecture was that dipping dots are made by dripping melted ice into a bowl of liquid nitrogen. The nitrogen is so cold that it freezes the ice drop into a ball-like shape in a flash!
Contribution by Will Sheehan