What is Cornstarch and What Does it Do?

I'll just get right into it: what is cornstarch and what does it do?

This question came up when I was chatting with a gluten-free friend who said she'd recently made a GF brownie mix that called for 1/2 cup of added cornstarch in the event of high altitude baking. Well, that's odd, I thought. I wonder why? That seemed like a lot of cornstarch to me. Maybe there are some things I don't know about cornstarch?

And so I figured, for my reference and yours, I'd come up with a roundup of what cornstarch is, what it does, and how to use it in your baking. Ready? Set? Let's go.

Cornstarch: what is it? 

The short version? Cornstarch is derived from the endosperm (tee hee) of corn kernels, which is ground into a find powder. It's used primarily as a thickener and binder both in savory and sweet cooking and baking.

Cornstarch: how is it made?

The long version? It's sort of confusing, but here's what I gleaned from the International Starch (really) page. First, corn is steeped in hot water for up to 48 hours. The germ is then separated from the endosperm, and still steeping, they are both, respectively, ground. Starch is separated from the steeping liquid, the remaining cereal germ, and corn gluten--mainly in centrifuges and hydrocyclones (a cyclone-shaped device). The starch is then modified by applying different reaction conditions - temperature, pH, additives. This process creates the corn starch with unique and reliable properties we use for our culinary projects. 

Key roles cornstarch plays in baking

Lemon meringue pie

Cornstarch as a thickening agent

Cornstarch can be added as a thickener to a variety of mixtures, from gravy to pie fillings to custards or cake fillings. It has more power, ounce for ounce, than flour, which is also used for this purpose; increasingly, the fact that it is also gluten-free is attractive to bakers, enabling them to make gluten-free pie fillings and custards. 

Here's what happens when cornstarch is added to the mix: heat causes the starch to bind with molecules of water, and the starch begins to swell as it absorb the liquid. When the mixture comes to 203 degrees F, the starch will have expanded to about 10 times its size while still in powder form. However, this expanding is finite. You can bring cornstarch-enriched sauces or mixtures close to a boil, but don't let them fully boil and don't stir too vigorously. The starch will start to deflate, erasing the entire purpose of adding it to your mixture. 

The cornstarch will not only become thicker in heat, but as it cools, it will set, so it's a great way to further solidify desserts tending toward gooey such as the filling of Lemon meringue pie, without the cloudy color that flour might impart.

There are considerations for using cornstarch as a thickener. According to this website,

• If you add cornstarch directly to a liquid, it can get clumpy, especially if added to a hot mixture. First, make a slurry of equal parts cornstarch and a cold liquid. Add this liquid paste to the mixture you want to thicken for better results. 
• Cornstarch doesn't react well with acidic ingredients. Tapioca starch or arrowroot will work better for thickening acidic mixtures.
• Cornstarch imparts a glossy, translucent sheen to the mixtures it thickens, so it tends to be used more in sweets rather than savory sauces. 

Cornstarch in cookies and cakes

Cornstarch not only thicken sauces and mixtures, but it can be used in baked goods such as cookies or cakes, too. It is said that cornstarch used in combination with flour can "soften" the harsh proteins of flour, making a more tender baked good. Anecdotally, I can tell you this is true. A recipe such as shortbread which employs part flour and part cornstarch yields a cookie with the perfect crumb: crumbly, but not fall-apart. Tender and delicate, but in a way that the cookie still holds its shape.

As I learned on a King Arthur Flour forum, it is also one of the secrets of cake flour.

Cake flour has been treated with chlorine gas which acts not only as a whitening agent, but also has a maturing effect on the flour. It damages the proteins that form gluten so that these will not form the long stiff chains and networks that make good bread, but also breaks down starches so that these will absorb more water. These hydrated starches then "gel" during baking to provide an alternate structure (alternate to gluten formation) which is desirable for cakes; tight, even crumb, moist, very tender.

You can make your own cake flour substitute, by the way. All you have to do is add two tablespoons of cornstarch per cup of all-purpose flour for a recipe. While it won't yield exactly the same results, it will certainly yield a more delicate baked good than all purpose flour alone. 

Cornstarch as an anti-caking agent

The difference between confectioners' sugar and granulated sugar? Primarily texture--confectioners' sugar has been finely ground (and you can make your own, at home, btw!)--but it's also the fact that confectioners' sugar is mixed with a small amount of cornstarch. The starch acts as an anti-caking agent by keeping moisture and condensation from forming the sugar granules into lumps.

Cornstarch isn't just used to discourage moisture from ruining your sugar. If you buy shredded cheese in the supermarket, chances are it has cornstarch in the mix--this keeps the moisture and condensation from making your cheese slimy. However, with cheese, there is a caution involved. The starch can turn brown quicker than the cheese in heat, so it can give a false indication of doneness. 

Frequently asked questions

Still curious about cornstarch? Here are some answers to commonly asked questions.

Why is cornstarch used so often in gluten-free baking?

Probably first and foremost because it's naturally gluten-free. Both cornstarch and flour are considered "cereal starches"--but the main difference is the aforementioned gluten. Flour has it; cornstarch does not.  But, you know, it also adds structure to baked goods, and this can be helpful when they lack the "glue" of gluten. 

Is it possible I know this stuff by a different name?

I've seen it as "corn starch" and "cornstarch"--I prefer the one-word variation. You'll see it referred to as such in US and Canada; in other countries, it may be called "cornflour"--not to be confused with cornmeal. 

My cornstarch got all clumpy in my pie filling. What's up? 

Nobody likes clumps and lumps in what should be a smooth pie filling. To avoid lumps, make a slurry (equal parts cold liquid and cornstarch) before incorporating the starch into the pie filling mixture. 

I'm sure I did everything right, but the starch didn't thicken my mixture.

Check the expiration date. Cornstarch does not last forever, and an advanced age can very much affect its thickening abilities.

Other possible causes: the mixture got too hot and the starch broke down; you overstirred and the starch broke down.

Help! My pie filling began "weeping". Is the cornstarch to blame?

Cornstarch can thin as it stands. The technical term is "syneresis", and it is characterized by a liquid "weeping" from the filling. It tends to happen more with mixtures including eggs or a lot of sugar. One of the culprits can be overstirring--this can break up the starch and make it thin out. Be sure to follow the instructions on your recipe to ensure that you are following the specified guidelines for how to treat the cornstarch mixture.

Don't have cornstarch?

Here is a list of some substitutes you can use in baking.  

Can I use cornstarch instead of flour?

Go ahead and give it a try. Cornstarch has twice the "thickening" power of flour, so you won't need as much. This helpful table will assist in substitution amounts. 

Recipes with cornstarch

• Lemon meringue pie in a chocolate crust (CakeSpy)
• Chocolate chip cookies (Sally's Baking Addiction)
• Shortbread (CakeSpy for Craftsy)
• Alfajores (CakeSpy)
• Marquesote (CakeSpy)

What's your favorite recipe containing cornstarch?

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Tapioca Pudding with Coffee Syrup and Caramelized Tapioca

Lucky you, dear readers! What we've got here is a guest recipe and excerpt from the fantastic new book Brazilian Food by Thiago Castanho and Luciana Bianchi. 

This is a really lovely book, with photos as vibrant as what I imagine Brazil to be (having never been, it's all imagination for me!). The recipes are accessible, flavorful, and interesting--and exotic. It's a cookbook to dream on, and I think it would make a nice holiday gift!

And, well. Even if none of that intrigued you, the fact is this: the cover features rainbows.

 Note: the photo and recipe in this post are used with permission from Brazilian Food by Thiago Castanho & Luciana Bianchi, Firefly Books 2014, $39.95 hardcover.

‘Bolo podre’ com calda de café e tapioca caramelizada 

Tapioca pudding with coffee syrup and caramelized tapioca 

This is a traditional pudding of the Amazon region. It does not contain wheat but granulated tapioca flakes, usually moistened with coconut milk. We eat it in the morning or late afternoon, but it is always accompanied by a cup of freshly brewed coffee. 

Serves 10 

* 2 vanilla beans   

* 1/2 cup (50 g) unsweetened, finely shredded dried coconut 

* 2 cups (500 ml) whole milk  

* scant 1 cup (200 ml) sweetened condensed milk  

* scant 1/2 cup (100 ml) unsweetened coconut milk 

* 1 cup (120 g) farinha de tapioca (granulated tapioca) or Farinha de Tapioca substitute (see page 82)  

* oil, for greasing  

Coffee syrup   

* 2 ¾  oz (80 g) rapadura or unleveled . cup (80 g) dark brown sugar 

* 1 cup (250 ml) hot espresso coffee 

Caramelized tapioca 

* unleveled . ¾ cup (100 g) farinha de tapioca (granulated tapioca) or Farinha de Tapioca substitute (see page 82) 

* unleveled . ¼ cup (60 g) superfine sugar 

1. Cut the vanilla beans in half lengthwise, and scrape out the seeds with the tip of a knife. Put the seeds, bean pods, shredded coconut, and all the milks in a saucepan. Place over medium heat, and cook, stirring constantly, until the mixture reaches scalding point. Discard the vanilla bean pods. 

2. Put the farinha de tapioca in a large bowl, and add the hot milk mixture. Stir well. Pour the pudding batter into a generously oiled 12 x 4.-inch (30 x 11 cm) loaf pan, and refrigerate it for 3 hours, or until it is firm. 

3. To make the coffee syrup, combine the rapadura and . cup (60 ml) of water in a saucepan. Heat for 2 minutes, stirring until the rapadura has dissolved. Add the coffee and remove from the heat. 

4. For the caramelized tapioca, combine the farinha de tapioca and sugar in a saucepan, and heat gently, stirring constantly, to melt the sugar. Cook until the caramel is a light golden brown. Pour the mixture into a nonstick baking pan and let cool. Store in an airtight container. 

5. Transfer the chilled cake to a serving board, and sprinkle with the caramelized tapioca. Serve in slices, accompanied by a drizzle of coffee syrup. 

Tips from Thiago: When pouring the pudding batter into the pan, press it down gently to pack it together and prevent it from falling apart when it is removed from the pan. 

Baker's Dozen: A Batch of Sweet Links

Today's links are brought to you by the color RED. 

Need a good way to use up all that leftover pie? Pumpkin pie shakes for all! (CakeSpy)

One of my favorite Christmas cookies: pistachio cookies. (CakeSpy)

Another fave: Stained Glass Cookies. Get ready for compliments if you make these! (CakeSpy for Craftsy)

Very intrigued: 7-up biscuits! (Bake.Frost.Repeat)

Cardamom rolls: so spicy and delicious-looking! (Fresh April Flours)

A helpful primer on cake knives. (Bakery Boy Blog)

No-bake peppermint cheesecake. This one's a showstopper. (Beyond Frosting)

Cappuccino eggnog donuts. So into these. (The First Year) 

Mini gingerbread house mug kits by my friend Not Martha. (Not Martha)

Savory whipped cream! Really?? Really. (CakeSpy for Craftsy)

DIY horchata. Or, add rum and make it "rumchata". (CakeSpy)

French Toast Swirl Sticks. I'd go there. (Pepperidge Farm)

Interesting: a historian chases down the history of baby food. (Saratogian)

Brown sugar chess pie. YES. (Grandbaby Cakes)

Cherry buttercream. It's a winner. (CakeSpy) 

Book of the week: CakeSpy Presents Sweet Treats for a Sugar-Filled Life. Yes, MY book! Because it's a great holiday gift.

How to Draw Food

From discussing boneless, skinless chicken breast versus drumsticks to watermelon and ice cream, I will teach you how to draw food just right. Read the full post here.

Best-Ever: Pumpkin Pie with Sweetened Condensed Milk

If pumpkin pie made with evaporated milk simply stopped existing today, I wouldn't really care. Because even though that's the "back of the box" classic version, I prefer mine with sweetened condensed milk.

Adding sweetened condensed milk not only saves you the trouble of measuring out sugar, as it provides all the sweetness your pie will need, but it also imparts a creamy, rich flavor. It's perfectly accented with a little salt, which takes the pie from earthy to ethereal, and completely crave-worthy. 

It's also almost sinful how easy this pie is to make, so instead of using pumpkin pie spice I used all the spices separately. It made the recipe seem more impressive, I think. 

I consider this the best way to eat pumpkin pie, and I hope you will, too. 

Pumpkin pie made with sweetened condensed milk

Makes one 9-inch pie (8 servings)

• One 9-inch pie crust, unbaked (I prefer the King Arthur method)
• 1 teaspoon ground cinnamon
• 1/2 teaspoon ground ginger
• 1/4 teaspoon ground cloves
• 1 teaspoon salt (note: I like my pie fairly salty. If you don't, use 1/4 to 1/2 teaspoon)
• 2 large eggs
• One (15 ounce) can plain pumpkin puree
• One (14 ounce) can sweetened condensed milk

Procedure

1. Position a rack in the center of the oven; preheat the oven to 425 degrees F (212 degrees C).
2. Roll the pie dough to a circle about 12 inches in diameter; place it into the pie pan and crimp the edges. Keep the dough refrigerated while you prepare the filling.
3. In a small bowl, stir together the cinnamon, ginger, cloves and salt. Set aside.
4. In a large bowl, beat the eggs; stir in the pumpkin and the sugar-and-spice mixture. Once well incorporated, stir in the sweetened condensed milk (it may incorporate better if you add the milk in three additions, ensuring that each addition is fully mixed in before adding the next). Pour the filling into the prepared pie shell.
5. Bake for 15 minutes, then lower the oven temperature to 350 degrees F. Bake for an additional 40 to 45 minutes, or until a knife inserted into the center comes out clean. Cool on a wire rack to room temperature. Serve at room temperature, or refrigerate the pie and let it sit at room temperature for 30 minutes before serving. If desired, serve topped with whipped cream.

PS: Pumpkin pie not for you? Here are some other pies and ideas for Thanksgiving from around the web that I suggest.

• Above: a sweet tutorial from the cute new book Sweet Treats for the Holidays: Edible Creations for Halloween, Thanksgiving, Christmas, and More
• Salty Honey Pie. I love bringing the "salted" trend to other things aside from caramel! (Annie's Eats)
• Peanut butter pie. Because, why not? (Mel's Kitchen Cafe)
• Fancy up your Kid's table at Thanksgiving this year! (Baked Bree)
• Learn what Christmas cookies think about Thanksgiving pies. Amusing! (CakeSpy)
• Buche de thanksgiving. (CakeSpy for Serious Eats)
• Cranberry-apple upside down cake. (Sally's Baking Addiction)
• Honey-pumpkin meringue tart. (Culinary Concoctions by Peabody)
• Chambord cranberry sauce! (Family Fresh Cooking)
• Homemade Parker House rolls! (CakeSpy for Craftsy)

Happy Thanksgiving, sweet ones!

Pop-Tarts That Should Exist

I'm thankful that Pop-Tarts do exist, but I wish these ones did, too. New print in my Etsy store!

Best of New Mexico: Homemade Blue Corn Pinon Bread

This one's dedicated to my Santa Fe friends.

If you've ever been to Santa Fe, New Mexico, you know that it is a special place indeed. The food reflect's the city's "tri-cultural" background: Native American, Mexican, and Spanish. With, of course, a touch of modern hippie and crystal-chaser in the mix. It makes for an interesting food scene, to say the least. (for my ultimate review of New Mexico sweets, check out this post!)

Two ingredients which are in frequent rotation in both baked goods and savories alike are blue corn and piñon nuts (pine nuts), respectively. One beautiful example of a delicious fusion of these ingredients was found in the beyond-locally famous atole-piñon pancakes served at Tecolote Cafe, a funky little breakfast place on Cerillos Road that is famous for their "no toast" policy. 

Well, me and everyone in Santa Fe was saddened when Tecolote shuttered their doors earlier this year due to a lease matter. I mourned those pancakes. 

Well, I am happy to say that Tecolote has found a new home and will be re-opening soon. In the meantime, I will "toast" them with a food that is inspired by them but that will never-ever appear on their menu: blue corn piñon bread.

Made with part blue corn flour and plenty of buttery piñon both in the bread and on top, this is a beautiful loaf with a novel, slightly blue-purple tint when looked at from the right angle. Taste-wise, it's lightly nutty; the blue corn gives it an intriguing, earthy taste. With mellow little lumps of rich piñon punctuating every bite, it's an absolute delight served with butter and a little salt.

Since it's made with whole wheat flour, too, it has a firm enough structure so that it is also appropriate for any type of dish you'd make with sandwich bread. 

Blue Corn Pinon Bread

Adapted from King Arthur Flour

Yield: 1 large loaf 

• 2 cups lukewarm water
• 2 1/4 teaspoons instant yeast (1 packet)
• 1 tablespoon honey
• 2 teaspoons salt
• 3 tablespoons soft butter
• 3 cups whole wheat flour, sifted
• 1 cup blue corn flour, sifted
• 1/4 to 1/2 cup piñon, to taste

 Procedure

1. Combine the water and yeast. Once the yeast begins to bubble lightly, proceed.
2. Mix all of the remaining ingredients with the yeast mixture in the order listed, reserving 1/4 of the piñon to top the bread later.
3. Knead, either by hand with a dough scraper or with a stand mixer, until it has progressed past a shaggy texture to a solid, slightly sticky mass. This can take up to 5 minutes by hand; less when using a mixer. It will never quite take on the smooth elasticity of wheat flour-only bread, but the extra moisture is necessary as the whole grains will absorb it. Place the dough into a lightly greased bowl, cover it, and let it rise at room temperature until it’s quite puffy and doubled in size, 1 to 2 hours.
4. Gently deflate the dough with your hand (a gentle pressing, not a knockout punch), and shape it into a fat 9″ log (it may still be slightly sticky; I used lightly oiled hands). Place it in a lightly greased 9″ x 5″ loaf pan. Sprinkle remaining piñon on top.
5. Cover the pan, and let the dough rise for 2 hours or even overnight, or until it has formed a crown which extends 1 inch or slightly more over the rim of the pan. Toward the end of the rising time, preheat the oven to 350°F. 
6. Bake the bread uncovered for 20 minutes. Tent it lightly with aluminum foil, and bake for an additional 15 to 20 minutes, or until it is golden brown on top, and when knocked lightly, yields a slightly hollow sound.
7. Remove the bread from the oven, and turn it out onto a rack to cool. When completely cool, wrap in plastic, and store at room temperature. 

Have you ever baked with blue corn flour before?

Easy Recipe: Horchata

Have you ever heard of horchata? No, I am not insulting you. Horchata is a delicious, milky beverage which is actually not always made with milk, but often rice or nuts ground into a "milk". It's nearly always spiced with cinnamon, and is often sweetened. It's common in Mexico, and common enough in New Mexico that I have become quite intimately knowledgable of the stuff.

Photo via flickr member sstrieu

Now that you're intrigued...how about making some horchata?

It's so easy and tasty that there's no reason for you to say no. And I'd bet that it's pretty likely you have a lot of the ingredients on hand already!

There's nothing to lose. Make it now. This version does have milk, which I think makes it extra-nice. You don't have to add it if you don't wanna. And oh, if you wanna get really naughty, add some rum!

Easy Horchata

Makes 2 servings

• 1/2 cup long grain white rice, UNCOOKED
• 1 1/2 cups water
• 1/4 cup whole milk* (see note above)
• 1 teaspoon vanilla extract
• 2 teaspoons cinnamon
• 1/4 cup sugar

1. In a blender, combine the rice and water. Mix on high for about 1 minute.
2. Add the rest of the ingredients right to the blender, and let it steep for 3 hours at room temperature. This is letting the flavors come together in a very pleasant way.
3. Strain the mixture, and pour it into a pitcher. Serve chilled (I prefer to chill it in the fridge rather than serving with ice, as I feel that it dilutes the mix).

Enjoy!

Great for Holiday Baking: Plush Puffs Marshmallows

Commercially made marshmallows aren't a go-to confection for me, because so many are inferior in quality and flavor. However, a homemade marshmallow is a different thing entirely: pillowy, sweet, and just begging to be popped on top of a rich cup of hot chocolate.

I was happy to discover a company that creates marshmallows that really do approximate that unique homemade flavor and texture: Plush Puffs. They sent me a package of samples, and I was very impressed with the quality (note: the samples were free to me; I am not being paid to write this post).

They sent me their holiday flavors, which included Gingerbread spice, pumpkin pie, and peppermint marshmallows. Each of the flavors tasted season-appropriate, and had a wonderful, pillowy yet holds-its-shape texture. In looking at their website, I was delighted to see that they offer a huge selection of flavors, from vanilla bean to caramel swirl to lemon meringue to even a tantalizing-looking chocolate chip cookie inspired flavor. Oh, and they pride themselves on not using high fructose corn syrup.

While my experience to this moment has been eating the marshmallows out of hand, I can definitely see them playing a role in holiday baking, be it gingerbread s'mores, minty cocoa, or maybe a homemade holiday s'mores pop-tart? Hmmm....

What do you think I should bake with these seasonal marshmallows?

If you're intrigued, shop for your own marshmallows on the Plush Puffs website.