The Science of Buttermilk
Sundays are pancake day in our household. I make them with thick, tangy buttermilk and I separate the eggs, beating the whites for a fluffy, sky-high rise. Our two young daughters help out, adding the salt, stirring the batter; the older, who's four, takes her turn flipping them. Hundreds of flapjacks later, I've come to learn a few things about both kids and pancakes.
I've always made pancakes and waffles with buttermilk, following the conventional wisdom that buttermilk makes better, fluffier baked goods than those made with sweet milk. By nature, however, I am not inclined to trust traditional kitchen lore. If I'm told to scald milk, I don't bother. If a recipe calls for egg whites at room temperature, I leave them in the refrigerator until the last minute to see what happens (in fact, cold egg whites whip as well as warm ones). So I thought that, in the Cook's tradition, it was about time to put buttermilk to the test.
I like a thick pancake, so one Sunday I used one cup of flour, one-half teaspoon salt, one-half teaspoon baking soda, one cup of buttermilk, two tablespoons of melted butter, and one separated egg. I whisked the dry ingredients together in a bowl, beat the egg yolk lightly with the buttermilk and melted butter, and poured the liquid ingredients slowly into the flour mixture, stirring gently with a rubber spatula. Then I beat the egg white and folded it in. For the sweet-milk version I used one teaspoon of baking powder in place of the soda.
The resulting batters were remarkably different. The buttermilk batter started to rise immediately, looking a bit like a sponge for bread. The sweet-milk batter was thinner and denser, although it did thicken as it sat in the bowl for about 10 minutes before cooking. The buttermilk pancakes rose at least 50 percent higher, and had a fluffier texture. The sweet-milk pancakes were good, but more compact and somewhat tougher. There was no discernable difference in taste, which surprised me, since most baked goods made with buttermilk have a distinctive flavor.
I guessed that the acidity of the buttermilk reacts in a more pronounced manner with the baking soda than the sweet milk does with the baking powder. For a more detailed description, I turned to our technical consultant, Harold McGee.
According to McGee, double-acting baking powder is designed to create gas (carbon dioxide) at both room and baking temperatures (single-acting baking powder only creates gas at room temperature). If too much of the rise occurs at room temperature, gas begins to escape before the high heat has the chance to "set" the cake by trapping the carbon dioxide. When baking pancakes, however, the batter is not subjected to heat for very long, so less gas is developed during cooking, and the rise is smaller. You can make your own single-acting baking powder by adding a bit of cream of tartar to baking soda (for detailed instructions, see Biscuits, May/June, 1993 issue). This should give you a faster rise, more appropriate to pancakes.
Buttermilk, on the other hand, is full of lactic acid, which reacts at room temperature with the baking soda. As I observed in my test, the buttermilk batter started to rise immediately (this is why some buttermilk biscuit recipes recommend that biscuits sit 10 minutes before baking-- they begin rising at room temperature) and the final pancake was lighter and fluffier than the sweet-milk version. For quick cooking, buttermilk has a clear advantage.
When serving up breakfast that morning, I followed all of the rules drilled into me by our kids-- use lots of butter (if it melts, it doesn't count), make sure that some of the syrup spills onto the plate (so they can scoop it up with a spoon), and don't cut the pancakes ahead of time (they have to ask). Everything was served up perfectly and the kids were called to the table. They sat down, took one look at their two fluffy buttermilk pancakes and said, "Dad, we wanted waffles this morning." I guess pancakes are easier to figure out than children.