Cornstarch Crystal Conundrum aka Perfect Pudding

Cornstarch is very important to any cook or baker who has ever tried to thicken a filling or a sauce. It is effective and highly water soluble, so the resulting product doesn't look milky or cloudy like sauces thickened with roux can. It is a starch, which is a very long carbohydrate. Carbohydrates, after a long and extensive and way too complicated chemical reaction, are what provide energy for our bodies. Starches are produced by plants as a way to store the carbohydrates. Cornstarch is, believe it or not, a starch produced by corn.

Atoms consist of a nucleus (protons and neutrons) and an electron cloud. The number of protons in a nucleus determines what type of atoms they are. There are lots of ways that atoms interact with each other. When they get close enough that they share their electrons they are bonded and they become a molecule. These molecules in turn can react with each other and create much weaker bonds called intermolecular bonds. The strongest intermolecular bond is the hydrogen bond. When a hydrogen is bonded it loses it's electrons. Some atoms, like oxygen (and nitrogen), keep their electrons. So when a lot of molecules get together, the hydrogens and oxygens (or nitrogens) will try to pack close. Pure starches bond really closely to each other through these hydrogen bonds and the resulting groups are called crystals.

So what happens when you throw some of this starch in a pot with water and heat? The heat makes the molecules dance (more heat = more energy, more energy = more dancing), the faster they dance further they get away from each other. When they get far enough away the crystals break and the water rushes in and takes up the hydrogen bonding spots. The water get pulled in very tightly making it harder and harder for the water to move around, thickening the mixture.

Pudding is one of the many excellent foods that uses this reaction to its advantage. The other day I found myself craving something sweet. And pudding, homemade from scratch pudding, was what fit the bill. Or more accurately, what fit the current state of my pantry. Actually that isn't really true. I had to make some modifications to make this recipe work, and boy were they delicious. I was out of white sugar, so I used brown sugar instead. The original called for finely chopped bittersweet chocolate, all I had was chocolate chips. And like every other recipe I make I added a little extra vanilla. The original is by Martha Stewart. This is my version.

Comfort Chocolate Pudding

Ingredients

6 Tablespoons brown sugar

3 Tablespoons cornstarch

1-1/2 Tablespoons cocoa powder

pinch salt

1-1/4 cup heavy cream

1-1/4 cup milk

1-1/2 teaspoon vanilla

1 cup chocolate chips

1-1/2 Tablespoons butter

In a medium saucepan, whisk together sugar, cornstarch, cocoa, and salt. In a small bowl combine the cream with the milk and vanilla. Whisk some of the cream mixture into the dry ingredients until cornstarch is completely dissolved. Whisk in remaining cream mixture until smooth.

Place saucepan over medium heat. Cook, whisking constantly, until mixture comes to a boil and thickens (this will happen at about the same time so keep an eye on it). Remove from heat and add chocolate chips, whisking until chocolate is melted. Whisk in butter until melted.

Using a ladle, pour pudding into six dessert cups. Refrigerate until set, about 1 hour.