In Linlin Jensen’s class, students boil vegetables, make pasta and ice cream, and create other dishes to better understand the chemical principles of food and cooking. Kitchen Chemistry, says Jensen, a teaching professor of chemistry in the Eberly College of Science, is designed to “teach better chemistry and improve students’ understanding of how chemistry relates to their daily lives.”
When Jensen, a theoretical chemist, began teaching at Penn State in 2007, she noticed that many students “feared” chemistry. The chemistry department was also looking for creative ways in which to interest students in the subject, so Jensen came up with Kitchen Chemistry in 2014 and has been teaching the online course since 2015. “I like to cook and bake,” she says, “so that’s the route I took to come up with a class for students that, even if their goal isn’t to become an expert in chemistry, they use chemistry all the time.”
Chem 5 students purchase the basic ingredients they need to cook and bake simple dishes and in each of Jensen’s 12 lessons, they mix up recipes that help them understand chemical principles like boiling, freezing, acidity, fermentation, and caramelization. They learn about heat transfer, the impact of adding sugar and salt to food, the chemical reaction produced when adding baking soda or cream of tartar to baked goods, and how the way in which ingredients are measured can alter the outcome of a dish.
“You could measure a cup of flour by scooping it directly out of the package, you could sift it into the measuring cup, or you could sift it somewhere else and then scoop it,” Jensen says. “The chemical concept behind measuring is density and when you use different measurement techniques, you will end up with different densities.”
It goes without saying that her students’ favorite class is the one on homemade ice cream. And when it comes to their final assignment—“a recipe that they design as an experiment to understand a particular chemical aspect”—Jensen’s students get quite creative. “One year, a student who was allergic to eggs decided to use chickpea water to create a dish,” she says. Another student used a “reverse searing technique” for steak, cooking it in the oven at a very low temperature for 20-to-30 minutes to get the meat to an even temperature, then grilling it on a hot cast iron skillet for about a minute. The foolproof method for a nice, juicy steak is now Jensen’s go-to.
