Yeast consists of tiny living cells that make carbon dioxide as they breathe. Its bubbles puff up not only bread and cakes but also pizza. With the dough from the last experiment, you can see just what a difference yeast makes!
Dough #1 from the previous experiment
Dough #3 from the previous experiment
2 cookie tins or pie plates
Small can of tomato sauce
Pinch of oregano
A rolling pin or glass
56-112 g of cheese (mozzarella, parmesan or cheddar)
1 to 2 teaspoonfuls of olive oil
On a lightly floured board, punch the raised dough with your fists. Knead it for a few minutes and stretch it out or roll it with a rolling pin or the side of a glass to a circle six to eight inches in diameter and 1/4-inch thick. Leave the edges a little thicker, so they make a rim.
Put the rolled-out dough on an oiled cookie sheet or a pie plate. Let it rise for another 15 minutes.
Roll out the other piece of dough, the one that didn’t rise because the yeast was killed. Knead it and then roll it out into the same kind of circle.
Preheat the oven to 450°F (230°C).
Put a layer of cubed or grated cheese on each of the dough circles. Stir a pinch of marjoram or oregano into the tomato sauce. Then pour half of the tomato sauce into the centre of each pizza and spread the sauce in circles towards the rim. Top each with another layer of cheese. Place the pie plates near the bottom of the preheated oven. Bake each pizza for about 20 to 30 minutes or until its crust is brown.
Be sure to use a potholder when you take the pizzas out of the oven. Let them stand for about five minutes before you cut them. Taste each one.
This Is What Happens:
The pizza made from the raised dough puffs up even more and has a light, moist taste. The dough of the other “pizza” is unpizza-like-flatter, heavier, and not very tasty.
Science Behind It:
The yeast in the raised dough is still active and continues its action during your kneading and for part of the time that the pizza is baking. The other dough bakes as though no yeast had been added.