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Syneresis and other geeky jargon for cooks

Scrambled eggs should cook over low heat until they form tender curds. If you leave the pan on a burner too long or on too high heat, you may see liquid seeping from around the edges of the golden mixture. This is called syneresis (pronounced sin-er-EE-sis). Eggs in chafing dishes on breakfast buffets often weep like this.shutterstock

This is the first of a new column that will run biweekly and explore the intersection of culinary arts and kitchen science.

Take the lid off a container of yogurt that you’ve had in the fridge for a few days and you’ll probably see a watery layer on top that has separated from the creamy base. This curious phenomenon also happens when you leave scrambled eggs in the pan a minute too long. Or overcook a luxurious custard in a quiche. The golden filling suddenly starts weeping liquid. Food scientists, who have been studying this for decades, know it as syneresis (sin-er-EE-sis).

Scientific terms are no longer limited to chem labs and lecture halls. Ordinary cooks are learning the science behind how we cook and what we eat, transforming our approach to cuisine. It's all part of a revolution in food that is pulling down the boundaries once established between traditional disciplines of culinary arts and food science. At one time, you could go into a kitchen and become a chef or work in a lab on food science. Today, chefs, geeks, scientists, scholars, and everyday cooks are digging in.


In this "A Side of Science" column we will unravel kitchen mysteries and talk about innovative creations. You may know some already: why you plunge cooked green vegetables into ice water, or why you shouldn't rinse pasta after cooking. Others, like the difference between caramelization and the Maillard reaction, or the chemistry behind what makes pie crusts tender and flaky (no one wants to go to all that trouble and end up with something tough), may be new to you.

Now back to syneresis. It's the release of liquid from a gel, which is what happens — this is the geeky part — when a web of food molecules holding liquid in place contracts and pushes it out. It can be caused by simple aging (yogurt sitting in the fridge) or stress (too much heat under the egg pan). Aside from making crusts soggy when a quiche filling weeps, syneresis is harmless.

In 2010, when Harvard University first offered a course called "Science and Cooking: From Haute Cuisine to the Science of Soft Matter," the enrollment was so high, the college had to offer overflow classes in an auditorium; lines for the public lectures wound out the door and down the block. Up-and-coming chefs at the Culinary Institute of America in Hyde Park, N.Y., attend classes with titles like "Culinary Chemistry" and "Scientific Evaluation of Traditional Cooking Techniques."


Home cooks are using scientific theory to hone their kitchen skills, and they seem to have an insatiable appetite. MIT grad J. Kenji Lopez-Alt, managing culinary director of, has more than 36,000 Twitter followers (@TheFoodLab), and his new book, "The Food Lab: Better Home Cooking Through Science," was No. 1 in celebrity and TV show cookbooks on earlier this week — and it won't be released until later this month.

The ethos of today's food movement could be described with the motto emblazoned on British chef Heston Blumenthal's coat of arms, "Question Everything," says food and cooking science writer Harold McGee. "There are lots and lots of traditional ways of doing things, traditional dishes, ideas about what goes with what, and these days, all those things are being tried and tested and questioned," he says on the phone from his home in San Francisco.

McGee's 1984 groundbreaking book, "On Food and Cooking: The Science and Lore of the Kitchen," brought curiosity to a steady simmer. It was revised and expanded 20 years later, winning several awards, and remains standard issue in culinary schools and a go-to resource for anyone curious about food.

The popular author (@Harold_McGee on Twitter has more than 42,000 followers) is a visiting lecturer at Harvard's Science and Cooking course. He credits Ferran Adria, the Spanish culinary innovator of the now-shuttered El Bulli restaurant, whom many consider the world's greatest chef, with putting science on the map. "It was just the example of a wildly successful and wildly creative chef using science as one of many different tools for creativity," says McGee.


He adds that Adria decided to make his life's work coming up with cuisine people had never experienced before. Adria's approach of engaging the senses, emotions, and intellect, then adding an element of surprise, resulted in dishes such as spherified olives (liquid centers surrounded by a thin membrane of xanthan gum), carrot foam with hazelnut foam air and Cordoba spices, and Roquefort sorbet with hot apple and lemon jelly. He profoundly influenced the direction of culinary professionals, who called it "molecular gastronomy."

Now, food scientists are trading lab coats for aprons. The science began as a profession in the early 1900s, and traditionally, it didn't involve the cooking aspects of food, says Guy Crosby, PhD, the science editor for Brookline-based America's Test Kitchen and an adjunct professor at Harvard, where he teaches food science and technology.

The food science profession "was mostly involved with food safety, and food packaging and processing," says Crosby. When it involved going to the stove, those aspects "tended to be more the realm of home economists."

In 2012, Crosby and editors of America's Test Kitchen wrote "The Science of Good Cooking," which was on The New York Times best seller list for eight weeks (a follow-up book is in the works). The scientist ( points to the value of collaboration. "When you can get a team situation where you get food scientists working with chefs, it can work out really, really well," he says. He sees chefs increasingly seeking out scientists to expand the creative process.


The mash-up of science and cooking has gone viral. McGee calls this "the general geeking-out of enthusiasts," and says this includes "people who decided that they're interested in coffee, for example, and will get 10 machines, and will start a blog."

Lopez-Alt, who worked at No. 9 Park and Clio, and was an editor at Cook's Illustrated, says food geeks make up a large part of his readership, but home cooks, chefs, and even noncooks are logging in. The upper echelon of the food world is taking notice. "The Food Lab" column was nominated twice for a James Beard award.

All of this doesn't mean we're forgetting our great aunt's recipe for green bean casserole. Knowing the science of everyday cooking can free cooks from the constraints of recipes and let them become more creative, says Lopez-Alt. "It makes you a more adaptable cook," he says.

He insists science does not preclude tradition. "Food can be very soulful and meaningful, and understanding the science doesn't change that at all."

Valerie Ryan can be reached at