Purim Science: Baking Soda vs. Baking Powder

Purim starts tonight at sundown. If you want to try my grandmother's recipe for Hamantashen and you're all out of baking powder, you can make your own by mixing two parts cream of tartar with one part baking soda.
Hamataschen cookies
Apricot, chocolate Kiss and prune-filled Hamentaschen are traditional Purim treats made with science. Image: Kathy Ceceri

A few years ago, when the kids were studying chemistry, we made Hamantashen cookies for Purim and the question came up about the difference between baking soda and baking powder. We had done the baking soda and vinegar thing many times, so we already knew that mixing sodium bicarbonate with an acid releases carbon dioxide. When you bake, those little bubbles of CO2 make the bread puff up. The acid needed to start the reaction in a batter can come from yogurt, buttermilk, lemon juice, or even molasses or honey.

Baking powder = baking soda + cream of tartar. Image: Kathy Ceceri

But the recipe for Hamentashen from my grandmother's old cookbook called for baking powder:

  • 1 cup sugar
  • 1 cup oil
  • 3 eggs
  • 1/4 cup orange juice
  • 1/2 tsp salt
  • 2 tsp baking powder
  • 4-5 cups flour
  • Filling: canned poppy seed or lekvar (prune) filling; apricot jam; chocolate chips or Kisses
  1. Preheat oven to 350 degrees.
  2. Mix together everything except the flour. Add enough flour to make a soft dough, a little on the dry side.
  3. Form into a ball. Roll out about 1/4 inch thick on a floured board. Cut the dough into circles with a round cookie cutter or the rim of a glass. My grandmother's were always small and dainty, but in New York the bakeries they make 'em as big as your hand.
  4. Spoon some filling in the middle. To shape the cookie, pinch three sides up to form a triangle.
  5. Bake for 20 minutes, until the edges are brown.
Baking powder fizzes with water alone. Image: Kathy Ceceri

Baking powder is baking soda with the acid already mixed in, in the form of cream of tartar. When moistened, powdered acid combines with the baking soda and produces the requisite bubbles. Some baking powder is "double acting," meaning it releases most of the bubbles when heated, so that the leavening action doesn't expend itself while the dough is waiting on the counter to bake.

Purim starts tonight at sundown. If you want to try my grandmother's recipe for Hamantashen and you're all out of baking powder, you can make your own by mixing two parts cream of tartar with one part baking soda.

(Thanks to fellow Culinary Jew Rebecca Levey, whose tweet about finding some poppy seed Hamantaschen reminded me of this project!)