Introduction
The brownies looked perfect going into the oven—glossy batter, precise measurements, the kitchen smelling like dark chocolate and vanilla. Thirty minutes later, they emerged flat as pancakes with a weird metallic aftertaste that no amount of powdered sugar could hide. Maya Chen, a pastry chef at a Brooklyn bakery, sees this exact scenario play out in her beginner baking classes at least twice a month. The culprit? Someone grabbed baking soda when the recipe called for baking powder, or used them interchangeably thinking they're basically the same thing.
They're not. And this mixup ruins more home-baked goods than almost any other kitchen mistake.
Why this confusion happens so often
Both come in similar boxes. Both sit in the baking aisle. Both make things rise. The names sound nearly identical. It's no wonder people treat them like twins when they're actually distant cousins with completely different jobs.
Chen explains it simply: "Baking soda is pure sodium bicarbonate—it needs an acid to activate, like buttermilk, yogurt, lemon juice, or brown sugar. Baking powder already contains acid mixed in, so it activates with liquid and heat." When you swap them without adjusting the recipe, the chemistry falls apart. Your cake either doesn't rise or tastes soapy and bitter.
The confusion multiplies because some recipes use both. Chocolate chip cookies might call for baking soda to create spread and crispy edges, while banana bread uses baking powder for a tender, even crumb. Understanding which does what saves you from dense muffins and hockey-puck scones.
What actually happens when you mix them up
Using baking soda instead of baking powder
Your batter rises too quickly, then collapses. Without enough acid to neutralize the sodium bicarbonate, you're left with a bitter, almost metallic flavor that coats your tongue. Chen once watched a student make chocolate cupcakes with a tablespoon of baking soda instead of baking powder. "They puffed up dramatically, then sank in the middle and tasted like licking a penny," she says.
The brown spots you sometimes see on baked goods? That's excess baking soda reacting with sugars, creating dark patches with an unpleasant taste.
Using baking powder instead of baking soda
The opposite problem occurs—not enough rise, especially in recipes designed around baking soda's reaction with acidic ingredients. Cookies stay thick and cakey instead of spreading into thin, crispy rounds. The flavor stays flat because you're missing that subtle tang baking soda brings when paired with buttermilk or molasses.
Chen points out that baking powder also contains cornstarch, which affects texture. "Your cookies might feel slightly powdery or dry because you've added starch the recipe didn't account for."
