Baking Powder to Baking Soda

Substituting baking powder with baking soda

Here is the rule most bakers go by: 1 teaspoon of baking powder ≈ 1/4 teaspoon of baking soda + 1/2 teaspoon of cream of tartar (or another acid such as vinegar, lemon juice or buttermilk). You cannot swap them 1:1. Baking soda (sodium bicarbonate) is a pure base. It only releases CO₂ once it meets an acid in the batter, which means that with no acidic ingredient around you end up with a soapy, metallic taste. Baking powder, on the other hand, already bundles baking soda with a powdered acid (cream of tartar or sodium aluminum phosphate) and a stabilizer (cornstarch), so it does its job in any neutral batter. Say a recipe asks for 4 g of baking powder and all you have is baking soda. Use ≈ 1 g of baking soda plus 2 g of cream of tartar, or 1 g of baking soda plus 1 teaspoon of vinegar/lemon worked into the batter.

Applications and context

You will run into this with quick breads, pancakes, waffles, cakes, cookies, muffins and scones. Recipes built around buttermilk, yogurt, lemon, cocoa, honey or molasses already carry their own acid, so they usually call for baking soda. Where the base is neutral (plain milk, water), baking powder is what you want.

FAQ

Is baking soda stronger than baking powder? Yes, by a fair margin, roughly 3–4× more potent. That is why the conversion calls for so much less baking soda than the original baking powder amount.

Can I just use double the baking soda? No. With no acid present it never reacts fully, and you are left with a bitter taste. Pair baking soda with cream of tartar or an acidic liquid every time.

Does baking powder expire? It does. Around 6 months after opening it starts losing strength. Drop a teaspoon into hot water to check; if it doesn't bubble vigorously, throw it out and buy fresh.