Which ingredients can provide acid for baking soda in a recipe?

To ensure proper leavening and prevent an alkaline, soapy taste or discoloration in your baked goods, baking soda must be paired with an acidic ingredient to trigger the release of carbon dioxide.12

Common ingredients that provide the necessary acidity include:

• Natural food acids: Vinegar (which contains acetic acid) and sour milk (which contains lactic acid) are effective, though they often react very quickly.1
• Tartaric acid: Often found in many foods, this is a common acidic reactant used to facilitate the rise of cake batter.3
• Commercial leavening acids: These are specifically developed to maintain a controlled rate of gas release. Common compounds include:
  • Cream of tartar (potassium acid tartrate)
  • Sodium aluminum sulfate (alum)
  • Sodium acid pyrophosphate
  • Various forms of calcium phosphate

Alternatively, you can use baking powder, which is a pre-mixed combination of baking soda and an acid, stabilized with starch to ensure the reaction only occurs when moisture is added.34