The Art of Darkness

Ever looked closely at an Oreo, the world's best-selling cookie? I admit that I usually devour them too rapidly to permit full examination of the iconic treat, which is depicted in Naomi Weissman's clever Periodic Table of the Desserts, which I have prominently posted in my kitchen. It holds the number 76 spot, under the Latin name "cuppedia optima" (best cookie), and, in keeping with chemists' conventions, is abbreviated Os.

However, if you carefully inspect an Oreo you will notice two things. First, a series of four-leaf clovers is embossed on both sides of the cookie. Second, despite being described on the package as a "chocolate sandwich cookie" made with "real" cocoa, an Oreo is not chocolate colored. It is, in fact, black.

That's because while Oreos are indeed made with real cocoa, it has been so alkalized that it is no longer brown. To appreciate this, you have to know a little about a process called "Dutching."

It all started with Coenraad Johannes van Houten, who worked in his father's chocolate business in Amsterdam in the early part of the 19th century. Using a hydraulic press he perfected an inexpensive method for extracting cocoa butter from the cocoa liquor which is produced from the nibs of cocoa beans. The solids left behind are then ground into cocoa powder.

But he didn't stop there. In addition he treated the resulting cocoa powder with a solution of potassium or sodium carbonate, which alkalized it, changing its pH and making it less acidic. (The Aztecs did much the same thing using wood ash.) This process, given the nationality of its inventor, was dubbed "Dutch-processing" or "Dutching."

With batter that clearly shows the impact of black cocoa, the secret ingredient in Oreos, Black Velvet Cake is a darker hue than any other you'd make with ordinary cocoa powder.Tom Harte

In addition to making cocoa less acidic, Dutching gives cocoa a more mellow flavor and, more obviously, a darker color. Compared to Dutched cocoa, natural cocoa is reddish brown. In fact, Red Velvet Cake originally got its reddish color as a consequence of a chemical reaction between non-alkalized or natural cocoa and baking soda (before cooks wanting a more intense color started adding whole bottles of food coloring to the recipe.) Dutched cocoa, on the other hand, is dark brown.

Black cocoa goes beyond natural cocoa powders like Hershey's or Dutched cocoa like most European brands. It is ultra or super alkalized. As a consequence it goes beyond brown all the way to black. Some say it gives cocoa a more earthy taste, which is not surprising because it looks a little bit like dirt.

Addictive though they are, Oreos are not the primary reason to use black cocoa. Even a tablespoon or two added to a recipe calling for natural cocoa can add impact to cakes, brownies, quick breads, ice cream, cookies, and, of course, homemade Oreos. There are just a couple of caveats to consider: black cocoa is low in acid and practically fat-free, so adjust your recipes accordingly by using baking powder, not baking soda, and adding extra fat. Otherwise, there's no reason to be afraid of the dark.

Compared to natural cocoa powder, which is typically reddish-brown, black cocoa is far darker and essentially black.Tom Harte

Black Velvet Cake

This behemoth of a cake, a distant cousin of Red Velvet Cake, is adapted from a recipe on the Sugar Geek Show blog.

Cake:

• 2 3/4 cup flour
• 1 1/2 sticks butter
• 2 1/4 cups sugar
• 1 cup black cocoa
• 1/3 cup semi-sweet chocolate chips, melted
• 4 eggs
• 1 teaspoon salt
• 2 teaspoons baking powder
• 1/2 cup strong hot coffee
• 1 cup warm buttermilk
• 1/2 cup vegetable oil
• 1 tablespoon vanilla

Whisk together flour, baking powder, baking soda, and salt and set aside. Whisk together melted chocolate, cocoa, coffee, vanilla, and oil, then add buttermilk, whisking until combined. Cream butter and sugar until fluffy. Add eggs, one at a time. At low speed add one-third of dry ingredients and one-third of chocolate mixture and mix until incorporated. Repeat two more times. Divide batter between two greased 9-inch pans and bake until tester comes out just barely clean. Do not overbake. Cool completely before frosting.

Frosting:

• 16 ounces cream cheese
• 2 sticks butter
• pinch of salt
• 7 cups powdered sugar
• 2 teaspoons vanilla

Beat together cream cheese and butter until combined. Add salt and half of powdered sugar, beating until smooth. Add vanilla and remaining powdered sugar, beating until frosting is fluffy.