What is Molecular Gastronomy?
Rebel Eats star and creative culinary man Justin Warner demystifies this transformative field of food science.
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If you aren’t familiar with the term molecular gastronomy, spend a few hours watching Cooking Channel or Food Network and you’re bound to get a glimpse of this weird, wonderful food science. You could see chefs like Russell Jackson using liquid nitrogen (which apparently has uses far more delicious than dermatology) to make ice cream on Food Network Star or Homaro Cantu making edible “dirt” on Iron Chef America. These strange techniques might make you scratch your head. In the pages that follow, I’ll attempt to demystify the curious chemistries of molecular gastronomy.
So, What Is Molecular Gastronomy?
Well, that's tough to say. If you were to consult such esteemed resources as Wikipedia, you'd find an answer like: "It is a subdiscipline of food science that seeks to investigate the physical and chemical transformations of ingredients that occur while cooking." But I don't really agree with that. If that was the case, then the first caveman to figure out how to cook meat to delicious results was a molecular gastronomist. It is my belief that anyone who's ever made a mistake while cooking, and attempted to correct it, is a molecular gastronomist. Science is about finding the solution to a problem and cooking solves a problem: How can I make this ingredient edible or more palatable than in its previous state?
When The Questions Changed
In 1988, two scientists (physicist Nicholas Kurti and chemist Herve This) began using their vast scientific knowledge to address some problems –– and explore their curiosity –– in cooking. They perceived cooking as a phenomenon and sought to answer such questions as, "Why isn't my egg perfectly cooked according to the laws of thermophysics?" And, "How do I make my food look more like dirt?" Among all the questions they answered, however, their biggest achievement was probably coining the term molecular gastronomy itself.
Gastronomy vs. Cooking
Like any other "-onomy," this is a study: the use of scientific methods to understand what’s going on when we cook our food. By doing experiments, Kurti and This taught the world many things. They wanted to know why food behaves the way it does. For example, why does Grandma’s food taste better? Because grandma is old, and back in the day, people used to cook things slowly. (Cooking stuff at 176 degrees F –– which is perfect for a big roast –– is actually nearly impossible to do in a contemporary household kitchen.) So while chefs may do wild things on TV like making “caviar” out of coffee to put on a sundae, that is actually not molecular gastronomy –– it’s just cooking. Alton Brown, on the other hand, explores the reasons why food transforms the way it does on his show Good Eats, so in that regard, he is a molecular gastronomist.
Let's Talk About Texture
Now that we’ve established that what we see on TV is generally “molecular cooking” rather than gastronomy, we can start talking about examples of molecular cooking and their applications. A good molecular cook will try to amp up the sensory experience on all fronts, including the all-important texture. (I remember the first time I had raw abalone –– the texture conjured up the image of silly putty being pulled too quickly. When my teeth sunk in, the abalone snapped. I had never had snappy food before and it blew my mind.) I believe that the coolest thing about our mouths is that we can use them for both taste and touch –– texture is just your mouth touching food. The most-basic textures are solids, liquids and gases, and it is the interplay between those that makes our mouths happy. (Gases are a tough thing to pull off in the kitchen, but with a little resourcefulness, you can taste gases.)
Setting the Stage with Gas
Though smoke is a mix of gases and solids, for the sake of texture, I am going to call it a gas. I’m a big fan of using The Smoking Gun. (The manufacturer recommends you use its branded wood chips, but I can attest to the fact that any old chips will do.) Having a lamb dinner? Gas your house with rosemary to set the stage. Smoke some freeze-dried strawberries to sweeten the air for dessert. (Imagine if movie theaters didn’t smell like popcorn!) I used to work with a chef who would walk through the restaurant before service with a pan of smoking garlic. It cozied up an otherwise spare and chilly restaurant. You’d be very surprised at how an aroma can change the feel of a space and impact people's sensory experiences.
Solids, Liquids and Everything in Between
Most of the molecularly influenced foods you see on TV or in a restaurant rely on turning a liquid into a solid or vice versa, and this is the space where the bulk of techniques exist. Since most liquids are largely composed of water, our normal methods for turning liquids into solids are limited (to wit: freezing). But when you introduce hydrocolloids (culinary whiz buzzword!) to a liquid, these ingredients cause the liquid to become solid or semisolid. They are composed of hydrophilic polymers, which somehow cause the water molecules to stop moving and form a solid (in layman’s terms).
Hydrocolloids in Action
So how can a humble home cook use hydrocolloids in the kitchen? Easily. In fact, you probably already have one in your pantry: cornstarch. With twice the thickening power of flour, cornstarch can turn a boring liquid into a clingy sauce or finesse flavored milk into the “custard” of your dreams. (Custard is in quotes since, despite being able to make custardlike consistencies out of liquids, without eggs, they actually aren’t custards at all.) Just note, cornstarch is thermo-irreversible, meaning once your mixture heats up, you won’t be able to undo the gelification. Also, strong acids lower its ability to function, so maybe don’t try out that egg-free lemon custard first. You’ll need a kitchen scale to experiment with hydrocolloids; most of the recipes on the Internet are done on a weight percentage scale.
Gelatin: Oh, the Possibilities
Next up, one of my favorites of all: gelatin. That’s right; those Jell-O shots you made in college were actually molecular cooking! Gelatin tolerates alcohol uniquely and is thermo-reversible, meaning that it can melt. I’ve gotten really experimental with gelatin. For example, by putting the ingredients of Caesar dressing into a gel cube, I was able to serve it on hot lettuce, amazing diners as the salad “prepared itself” tableside. For some boozy appetizers, cube sparkling wine and put it on crackers with cream cheese and smoked salmon. (Beware that pineapple, kiwi and papaya have weird enzymes in them that like to eat gelatin for dinner.)
Foams, AKA Eating Air
Gelatin can also let us eat air! Well, kinda. By adding a little gelatin to increase the viscosity of a normally unwhippable liquid, we can charge the liquid with nitrous oxide and make an edible cloud. (A cream whipper is required to do this.) When you disperse the gas into a slightly gelatinized liquid, the gelatin connects with the water to encapsulate air. Encapsulated air is just a bubble, and lots of bubbles equal foam. Foam is texture filled with flavor that dissolves in the mouth. Next time you're thinking of drizzling a sauce on a plate, look to gelatin and a cream whipper to amp up an otherwise boring dish.
And Then Came Agar
Agar, the seaweed-derived hydrocolloid, is readily available at most health-food stores. While gelatin takes a long time and requires a specific temperature, agar is both speedy and easy to use. (Caveat: It's a little grainy in texture.) Agar handles room temperature better than gelatin and is also a lot less wobbly, so it can be cut into squares, cubes, triangles and even noodles. Put some agar-ed, sweetened, salted, minted grapefruit juice in a thin layer in a baking dish, cut ribbons, top it with lump crab meat and creme fraiche, and boom! You’ve got crab salad where the noodles are both the sauce and the starch of the dish.
The Secret Behind Those Spheres
There is another harder-to-find hydrocolloid that deserves mention: sodium alginate, which gels when combined with calcium. Sodium alginate is our go-to for spherification, which is the process of turning a liquid into a shape that resembles caviar (i.e., a liquid encased in a sphere-shaped membrane, with a bit of help from calcified water or calcium-infused liquid).
Wondering how to use it? Make a sphere of salty lime juice as a chaser for a tequila party or put a few spheres of Alfredo sauce over some spinach fettuccine. The possibilities are endless, my friends.
Now we dive into the world of “dirts.” Dirt is a gross thing to eat, but imagine if your perfectly poached egg was anchored to the plate by a mound of bacon-drippings dirt. Dirts are liquids that have been turned into powdery, crumbly solids. This is done with fats and maltodextrin, which you might find on the ingredients list of a lot of processed foods. The process is simple: Blend maltodextrin with the fat of your choosing (e.g., olive oil, coconut milk, bacon fat, beef drippings) and watch it turn into dirt. Now you can make an olive-oil-and-rosemary-coffee-cake crumb, shrimp coated with curried-coconut-milk dirt or even bacon-dusted doughnuts. Thank you, maltodextrin, for being the crumbling chemical you are.
Last, From Solid to Liquid
The weirdest of all hydrocolloids is methylcellulose, which sort of turns solids into liquids. Methylcellulose forms solids at high temperatures and melts them at low temperatures, which is pretty much the opposite of everything that we’ve ever learned about everything. It keeps even the juiciest things solid in the oven, and then lets them spread out once you are ready to serve (think fruit tarts and pies). You could make an ice-cream base, wrap it in plastic wrap, poach it in hot water and serve it on top of cold apple pie. Apple pie is cold, ice cream is hot, mind is blown.
In my next rant, we'll talk about sous vide cooking and the importance of scientifically perfect temperatures. In the interim, feel free to hit me up on Twitter for all of your hydrocolloid needs. Foam on, my friends.