Here's why colder water makes better dough for yeasted bread and pizza.
When making yeasted doughs that undergo a long, slow fermentation in the refrigerator, such as many of our pizza doughs and the dough for our Pita Bread, we use ice water. Keeping the dough cold during mixing—especially when friction from a food processor is involved—allows the yeast to ferment gradually when the dough is refrigerated. During this proofing period, the yeast develops complex flavors and creates just enough gas bubbles to make the dough pliable. If the dough becomes too warm during mixing, the yeast ferments too quickly and the dough will overproof, becoming sour-tasting and excessively bubbly. Those extra bubbles make the dough prone to tearing when stretched.
To prove what a difference a few degrees makes, we prepared two batches of pita dough: one using 35-degree ice water made by mixing equal volumes of ice and water and letting the mixture sit for 5 minutes before using and another with 55-degree water made by briefly stirring a handful of ice cubes into 2 cups of water.
After an overnight ferment in the refrigerator, the dough made with the 35-degree water had a smooth exterior, had expanded minimally, and stretched with ease once it came to room temperature. The dough made with 55-degree water had many large bubbles just beneath its surface and was about 25 percent larger. We found it difficult to shape and stretch evenly.
The takeaway: For pizza, pita, and other doughs that ferment in the refrigerator, make sure your ice water is truly icy: Mix equal volumes of ice and water and let it sit for at least 5 minutes before using.