I was recently presented with the opportunity to attend a student-only lecture for a Harvard University undergraduate course called “Science and Cooking: From Haute Cuisine to the Science of Soft Matter.” So I did what any self-respecting (food) nerd would do—I threw on my finest plaid shirt and v-neck sweater, grabbed top cameraman Steve Klise, and got my butt to Cambridge.
For those of you who haven’t yet received your invitation to attend, I’ll explain.
Launched last year as a general education course, Science and Cooking was dreamed up a as way to promote scientific discussion among students (and the public) who like eating and talking about food, but could more or less care about science. It’s the academic equivalent of melting a pound of cheddar onto a bowl of steamed broccoli so that your kids will actually eat it—and just like with broccoli, it works. The class is wildly popular, as are the accompanying public lectures—and it’s largely thanks to the scary-good lineup of guest speakers. Harvard has procured a veritable “who’s who” of the science-obsessed breed of high-end chefs and food personalities leading today’s culinary scene. Among the lecturers are Dave Arnold, Ferran Adrià , Jose Andres, David Chang, and Nathan Myhrvold. The list goes on and on, all helmed by multiple appearances from the godfather of food science himself, Harold McGee, and led by professor David Weitz.
The day I joined the class, the future leaders of America and I were treated to a talk by Wylie Dufresne, chef and owner of wd~50 on Manhattan’s Lower East Side. Chef Dufresne is famous for taking familiar dishes and flavor profiles and applying modernist techniques to alter their appearance and texture in drastic and novel ways. The result is food that is at once thought-provoking and comforting.
Dufresne’s silver bullet in the kitchen (and the entire focus of his 60-minute lecture) is an enzyme called transglutaminase (TG), or as he lovingly refers to it—meat glue. As the pet name suggests, TG is great at sticking meat together. But as Chef Dufresne went on to illustrate, its applications are far broader in reach. I’ll talk about some of those (“cheddar cheese”) in a bit, but first let’s cover the science (“broccoli”).
Bond… Covalent Bond.
First off, proteins are made up of amino acids, and for most intents and purposes there are 20 (nine of which we consider essential—i.e. we don’t make them in our bodies so we have to eat them). TG (most commonly sold under the brand name Activa) is an enzyme that forms a particularly strong connection, called a covalent bond, between two of the 20 amino acids: lysine and glutamine.
Covalent bonds are strong—how strong, you ask? Well, your hair’s main protein, keratin, is made of covalent bonds. Think about how hard it is to get your curly locks straight, or vice versa, and you have an idea of their strength. (For the curious: Perms are made possible by the use of strong, smelly chemicals that first break the existing covalent bonds so the hair can be curled, and then reform new ones to hold it in place).
While the chemistry is a bit intense, the application of TG couldn’t be simpler. Dust the surfaces of small pieces of meat, poultry, or fish with dry TG (alternatively the TG can be made into a slurry with water and brushed on), wrap tightly together with plastic wrap, and refrigerate at least 4 hours and up to 24 hours to allow the bonding to complete. And that’s it—unwrap the plastic and you are left with one uniform piece of meat where there were once only scraps. The appeal of the product from a thrift standpoint is undeniable, but it was in Dufresne’s more creative applications that I found real inspiration.
The Glue that Binds
If chefs designed the natural world, all animals would grow cylindrically. There’d be no cow shape, no pig shape, and certainly no chicken shape, because these irregular forms pose two perennial kitchen challenges: uneven cooking (thin cooks faster than thick) and trim waste. The solution? Meat glue. Dufresne showed a video of one of his cooks breaking down a whole cod, cutting each fillet lengthwise into half a dozen strips, painting each with a slurry of TG and water, and wrapping them all together with plenty of plastic wrap. Four hours later the cook unveiled a perfectly cylindrical piece of cod, just as nature never intended. Cut into thick rounds, each portion could be reliably cooked exactly like the next—and with no waste.
“Very cool,” you say, “but can one only stick cod to cod, and beef to beef?” Good question—you sound just like a Harvard student. Remember that the prerequisite for binding with meat glue is protein (and its amino acids glutamine and lysine), so most protein-rich foodstuffs can be stuck together. But the more important question, as Dufresne pointed out, is whether you actually want to. The chef remarked that he could certainly stick a duck breast and a lobster tail together and create the world’s first dobster, but how would he then go about cooking his creation? Dufresne’s point is that just because you can, doesn’t mean you should. And he should know: He’s been playing with TG in a professional kitchen for a long time. From his trial and error we learned a few exciting techniques that do work.
Perhaps Dufresne’s most famous meat-glued dish is spaghetti-like noodles made almost entirely of shrimp. Shrimp paste is combined with TG and then extruded directly into a temperature-controlled water bath, where the exterior of the noodles instantly cook and set the noodles’ shape. Another pasta made possible by TG is peanut butter noodles.
TG forms bonds with the peanut butter’s proteins, allowing it to be made into sheets and cut into noodles. And, since TG is heat stable, the noodles can be heated (or even boiled) for service. Anyone care for peanut butter noodles in their pad Thai?
Clearly the options seem limitless, but what if you want to glue things together that don’t naturally contain glutamine and lysine? Luckily for us, Chef Dufrense asked himself that same question, and then answered it with a simple solution: gelatin. By infusing gelatin-rich water (gelatin is a mixture of proteins and peptides) into things like radish slices and barley, he’s able to stick them together to great effect.
Ultra-thin sheets of radish are flexible and can be draped elegantly over a dish, while bonded barley cakes can be tossed directly into the deep fryer where they crisp and brown without crumbling apart.
While for many of you this is some excellent food for thought, I’m sure to others it sounds a bit like mad science. To those you of you in the latter camp, Chef Dufresne offered the following clarification about his crew at wd~50: “We’re not just guys in lab coats electrifying bunnies. We’re trying to find the best way to electrify the bunny.” The pursuit of perfection never looked so cool, yet sounded so strange.
My Chat with Wylie
Q: At America’s Test Kitchen we develop recipes for home cooks using pantry staples. Do you see any specific techniques from your work in a professional kitchen that could be translated for the home cook?
A: Pressures cookers are great. We pressure cook pine nuts and get a bean-like flavor and texture. Also, just order some TG/Activa on Amazon, get a good blender, and start playing. I would say the reason people eat at wd~50 is because of the time and effort it takes to make this stuff, not necessarily a lack of access to ingredients.
Q: Is your style of professional cooking more science or art?
A: I hate to bust everything up, but all cooking is science. And, yes there is an art to it. It’s both.
Q: You talk a lot about the durability of meat-glued foods—how can they be both extremely durable and then easy to chew? I’m thinking specifically of your barley cakes.
A: It’s all about striking the right balance. We try a lot of experiments and have a failure rate just under 50 percent. Eventually we find the right amount of TG, gelatin, etc. to add to get the results we want.
Q: Do you season the inside of composite meat-glued steaks?
A: Sometimes, it depends on their size and the end result we want. For the cod, we brine the individual strips before gluing.
Courtesy of Harvard, you can watch footage from Dufresne’s public lecture online:
Break It Down
Chemistry professor Greg Verdine breaks down proteins into amino acids.
The Beef Cylinder
Chef Dufresne describes a plated dish that features slices of meat-glued beef—medium-rare from edge to edge and well-seared around its cylindrical exterior.
Not Just For Meat
Meat-glued barley cakes stand up to deep frying and blowtorches.
What looks like a single piece of lamb is actually 10 lamb strip steaks stacked on top of each other and bonded with meat glue.