Baking Soda vs. Baking Powder
Updated August 15, 2026
Baking soda is pure sodium bicarbonate — it only rises when the recipe has an acid (buttermilk, yogurt, brown sugar, cocoa). Baking powder is baking soda with the acid built in, needing only moisture and heat. Soda is 3–4 times stronger: 1 teaspoon of baking powder ≈ ¼ teaspoon of soda plus acid.
| You need | You have | Do this |
|---|---|---|
| 1 tsp baking powder | Baking soda | ¼ tsp soda + ½ tsp cream of tartar (or pair with an acidic liquid) |
| 1 tsp baking soda | Baking powder | 3–4 tsp baking powder, and expect a saltier, denser result |
| Freshness test: soda | — | Fizzes hard in vinegar; no fizz = replace |
| Freshness test: powder | — | Bubbles in hot water; flat = replace (6-month life once opened) |
Why recipes use one, the other, or both
The leavener is matched to the batter's acidity. Buttermilk pancakes use soda because the acid's already there; a milk-based cake uses powder because it isn't. Recipes with both usually contain some acid — enough to justify soda (which also drives browning) but not enough to power the whole rise, so powder tops it up. That's also why swapping the dairy in a recipe (milk for buttermilk or back) can flatten it: you changed the acid the leavening was budgeted against.
Too much of either is worse than too little
Excess soda doesn't just fail to help — it tastes soapy-metallic and turns bakes oddly dark. Excess powder tastes bitter and can make cakes rise fast then collapse. When scaling recipes up, round leaveners down (see the scaling guide). And "double-acting" powder — which is nearly all of it — fires once when wet and again in the oven, which is why batters tolerate sitting a few minutes but still shouldn't wait an hour.
Quick answers
- Can I use baking powder instead of baking soda?
- Roughly — use 3–4× the amount. Expect subtle flavor and browning differences; it's a rescue, not an upgrade.
- Can I use baking soda instead of baking powder?
- Only with an added acid: ¼ tsp soda + ½ tsp cream of tartar replaces 1 tsp powder. Soda alone in an acid-free batter won't rise and tastes soapy.
- Why does my banana bread taste metallic?
- Too much baking soda for the batter's acid. Measure level, and don't "round up for insurance" — the insurance is the off-flavor.