What four things can be used as leavening agents in quick breads?

1. Baking Soda (Sodium Bicarbonate): This is an alkaline ingredient that reacts with acidic ingredients in the batter (like buttermilk, lemon juice, honey, or chocolate) to produce carbon dioxide bubbles, causing the bread to rise.

2. Baking Powder: This is a pre-mixed combination of baking soda, an acid (like cream of tartar), and a drying agent (usually cornstarch). It reacts with moisture and heat to release carbon dioxide, resulting in a light and airy texture.

3. Yeast: While less common in quick breads, yeast is a living organism that ferments sugars in the dough, producing carbon dioxide as a byproduct. This is the classic leavening agent in breads like sourdough or artisan breads.

4. Eggs: The protein in eggs contributes to the structure of quick breads, and they also act as a leavening agent by trapping air bubbles during mixing, resulting in a slightly lighter texture.

Bonus: Some quick breads also use whipped egg whites or steam as leavening agents.