Look through your favorite gravy recipe or read the back of a powdered sugar package, and you might notice a common ingredient: cornstarch. If humans could put this versatile starch in everything, we just might—it helps us fry crispy tofu and extract gold from rock, to name two of the jobs it does well. But odds are you’re underutilizing it in your own life.
What makes cornstarch so useful?
To fully realize cornstarch’s potential, you must understand it. At the most basic level, it’s a plant snack. Just like you might stuff granola bars into your coat pockets, plants stash away starch in case they get hungry later.
“[Starch] is a food storage for the corn,” says Matthew Steffens, a food industry consultant and a food science lecturer at the University of Massachusetts Amherst.
Corn plants create starch from excess glucose and reserve it. When they need it, they can break it back down into glucose to nourish themselves. The cornstarch you find in the store is made by grinding up corn, combining it with water, and extracting all the other parts of the corn you don’t need, such as the seed coating and protein, says Steffens.
Cornstarch’s versatility is partly due to its two main components: amylose and amylopectin. Amylose is a long, straight chain of glucose molecules, while amylopectin has lots of branches, and it’s the ratio between the two that informs how a starch behaves, Steffens says. Cornstarch is mostly amylopectin, which helps the ingredient thicken foods when mixed with hot liquids. And that viscosity is part of the reason you can find cornstarch in so many packaged goods, says Paul Takhistov, an associate professor of food engineering at Rutgers University.
“Texture is one of the four sensory attributes of food which is most recognized by the consumers, and therefore the viscosity is very, very important for the proper texture,” he says.
Cornstarch is also sought after by home cooks and food manufacturers because of its purity and low cost. You may have seen recipes that call for either wheat flour or cornstarch, and while both work well, cornstarch is purer, Steffens says. Flour has protein and fiber, which make it great for baking but a little less effective at thickening and frying because it has a lower concentration of starch. Cornstarch is also virtually tasteless, and, when heated with any water, mostly transparent.
Use cornstarch to thicken scrambled eggs
Mixing cornstarch into foods like sauces and gravies is one of the ingredient’s most common uses—it thickens ‘em up and creates that smooth, hearty texture you want from comfort food. This works thanks to a process called gelatinization, and all you need are water and heat.
Cornstarch fully gelatinizes when it is mixed with liquid and heated to between 140 and 185 degrees Fahrenheit (60 to 85 Celsius) for five to eight minutes. (If a recipe calls for you to bring the liquid to a simmer or boil, you’ll be at or above the correct temperature.) The heat causes the cornstarch particles to absorb the liquid and swell, providing thickness, Steffens says.
Gelatinization can also help make scrambled eggs creamier without having to use cheese. Mix some cornstarch into a bit of water before adding your eggs to the bowl and whisking. Then add everything to a pan on high heat with butter or oil. Let it sit for a few seconds while the edges bubble before removing the pan from heat and stirring the eggs with a spatula for about 12 seconds before immediately scooping them onto a plate. The starch may not have fully gelatinized during this time, but it will have absorbed and retained moisture that would’ve been lost to the heat, keeping the texture smooth.
But back to that first step about stirring cornstarch into water: You can’t just dump dry cornstarch straight into eggs or any other hot substance. It will seize into a lumpy mess because the outside of the cornstarch clumps will gelatinize, while the insides will stay dry. This is why most recipes ask you to make a “slurry” by stirring cornstarch into cool water before mixing it into hot liquid.
By doing so, you’re creating a suspension, evenly dispersing the solid cornstarch particles within the liquid. When you pour that slurry into the hot food, you’re heating individual granules instead of clumps, and your meal will thicken appropriately, Takhistov says.
Make fried food crispy
Frying with cornstarch also uses gelatinization, says Steffens. When you coat chicken in cornstarch, for instance, and drop it into hot oil, the moisture on the outside of the meat will gelatinize the cornstarch, and then the hot oil will immediately dehydrate it. You’ll be left with a crunchy film of starch, Steffens says.
“That film will hold in the moisture,” he explains. “It’ll just form a nice, crisp barrier.”
The same process applies when you mix cornstarch into a liquid frying batter, so the next time you make tempura or chicken wings, try substituting some flour for cornstarch to see if your meal comes out crispier.
Bake a fluffier cake
High-protein flour, like bread flour, gives your favorite sourdough its stretch and bounciness. Lower amounts of protein makes cakes, pastries, and other baked goods soft and airy. If you don’t have cake or pastry flour, you can replace a couple tablespoons of all-purpose flour with cornstarch to get the same effect.
“What you’re doing is you’re basically diluting out the protein content of that by using starch,” Steffens says. In this case, less is more.
Craft slime and silly putty
Cornstarch has uses outside of cooking too. You can use it to make silly putty with dish soap and water, for example. Cornstarch is great for making goos and slimes because it becomes a non-Newtonian fluid when mixed with water. This wacky substance is solid under pressure but liquid when left alone.
“It’s like running along the beach, on the sand close to the water. If you stop walking, you’ll start sinking in the sand. But if you run—hard as a rock,” Steffens says. “That’s how cornstarch behaves with water.”
So when you stir it furiously or mash it up in your hands, it feels solid, but when you scoop it up in your palm, it will run through your fingers like liquid.
Take care of yourself
Cornstarch is also great for absorbing oil or liquid stains on clothes or for making dry shampoo at home. This is because it’s dry, hygroscopic (it absorbs moisture easily), and a pile of it has a very high surface area because each of the particles is so fine, Steffens says. Each starch granule ranges from 40 to 50 microns in diameter, which Takhistov says is about the thickness of human hair.
That’s also why it’s a good anti-caking agent that manufacturers use to keep jelly beans from sticking together and shredded cheese from clumping in the bag. Any moisture goes right into the starch instead of turning into glue.
So if you splatter grease on yourself while making crispy fried cauliflower with cornstarch, just spoon some of this oil-absorbing powerhouse right onto the stain. Let it sit for 12 hours before washing, and it’ll be like it was never there.