Puff pastry and pate a choux leavening both rely on what?

• A. Air is the leavening for both
• B. Steam is the leavening for both
• C. Baking Powder is the leavening for both
• D. Yeast is the leavening for both

Answer: (B)

Steam is the driving force behind the rise in both pastries. In puff pastry, the water in the dough and the moisture in the fat layers turn to steam as it bakes; the laminated dough traps that steam between the layers, pushing them apart and creating the flaky, puffed sheets. In pâte à choux, the dough contains a lot of water, and as it heats, that water turns to steam, lifting the paste and forming the hollow interior that’s characteristic of choux products. Eggs help set the structure and add richness, but the main lift comes from the steam.