Crystallization: Fudge

We briefly touched on crystallization in a previous post, but today we actually addressed them in cooking.  Crystallization is a process in which atoms arrange themselves in a fixed ratio with set bonding patterns.  This can be either helpful or harmful in the cooking process; it is necessary for the creation of lollipops, hard candies, and a number of other confections, but very inconvenient when making chocolate fudge.  The creamy, smooth texture of fudge should not be marred by crystals.

So what exactly is crystallization, and how does it affect the foods we eat?  According the dictionary.com, a crystal is a piece of a homogeneous solid substance having a naturally geometrically regular form with symmetrically arranged plane faces.  Chemically, this geometric form is the set bonding pattern of the atoms.  Crystals can be made from ionically bonded atoms (between a metal and a nonmetal), and they can also be an arrangement of molecules (which are compounds of covalently bonded atoms).  

In the case of fudge, the sugar would be the crystallization culprit.  Amidst the silky goodness of the chocolate, small bits of sugar have the potential to attach to one another, forming larger, palpable crystals that mar the fudge.  To avoid this, certain tactics can be employed.  First, avoid introducing any seed crystals into the mixture.  Seed crystals, bits of already crystallized sugar, provide opportunities for other sugar molecules to attach into larger formations.  In addition, adding another substance to block the sugar molecules from connecting will almost guarantee a smooth consistency.  These anti-crystallization agents include honey and corn syrup.  In our fudge frosting, we utilized corn syrup.  

The fudge frosting was poured over a chocolate cake, ringed with KitKats, and decorated with two cows.  The result was an adorable pasture cake. 

We used Ina Garten's Beatty's Chocolate Cake Recipe:

Ingredients
Butter, for greasing the pans1 3/4 cups all-purpose flour, plus more for pans2 cups sugar3/4 cups good cocoa powder2 teaspoons baking soda1 teaspoon baking powder1 teaspoon kosher salt1 cup buttermilk, shaken1/2 cup vegetable oil2 extra-large eggs, at room temperature1 teaspoon pure vanilla extract1 cup freshly brewed hot coffeeChocolate Buttercream, recipe followsDirectionsPreheat the oven to 350 degrees F. Butter two 8-inch x 2-inch round cake pans. Line with parchment paper, then butter and flour the pans.
Sift the flour, sugar, cocoa, baking soda, baking powder, and salt into the bowl of an electric mixer fitted with a paddle attachment and mix on low speed until combined. In another bowl, combine the buttermilk, oil, eggs, and vanilla. With the mixer on low speed, slowly add the wet ingredients to the dry. With mixer still on low, add the coffee and stir just to combine, scraping the bottom of the bowl with a rubber spatula. Pour the batter into the prepared pans and bake for 35 to 40 minutes, until a cake tester comes out clean. Cool in the pans for 30 minutes, then turn them out onto a cooling rack and cool completely.
Place 1 layer, flat side up, on a flat plate or cake pedestal. With a knife or offset spatula, spread the top with frosting. Place the second layer on top, rounded side up, and spread the frosting evenly on the top and sides of the cake.

This is the fudge frosting recipe:
Place 1 cup granulated sugar, 1/2 cup baking cocoa, 1/2 cup milk, 1/4 cup butter, and 2 tablespoons corn syrup in a saucepan.  Bring to a boil, stirring constantly.  Remove from heat, place in an ice bath, and whip until cool.  Add 1 1/2 cups powdered sugar and whip until smooth.  Apply to your favorite cake.