Yield: 12 1-teaspoon uses (1/4 cup of mix)

Baking Soda Instead of Baking Powder: Exact Swap Ratios

Yes, if you add an acid. Make a homemade baking powder from baking soda, cream of tartar and starch, with US and gram measures, liquid-acid swaps, sodium per use and storage.

Prep Time5 minutes

Total Time5 minutes

Ingredients

Homemade baking powder (single-acting)

• 2 tablespoons cream of tartar, 21 g; the dry acid
• 1 tablespoon baking soda, 14 g; food-grade baking soda (sodium bicarbonate)
• 1 tablespoon tapioca starch, 7 g; cornstarch is the other starch King Arthur names for its swap

Instructions

1. Measure level spoonfuls. Level 2 tablespoons (21 g) cream of tartar, 1 tablespoon (14 g) baking soda and 1 tablespoon (7 g) tapioca starch into a small bowl.
2. Whisk until even. Whisk or sift the three powders together until the mix is one uniform color, so no pockets of plain baking soda remain.
3. Store airtight. Spoon the mix, about 1/4 cup in all, into an airtight container and keep it at room temperature for up to 6 months.
4. Use it in place of baking powder. Use 1 teaspoon of the mix for each 1 teaspoon of baking powder (our deduction, not a published ratio). Stir it into the dry ingredients and get the batter into the oven straight away.

Notes

Single-acting means the mix releases its gas when it gets wet, so it suits bakes that go straight into the oven. Store-bought double-acting powder is a different product.

Why 1 teaspoon of mix for 1 teaspoon of baking powder is our deduction: King Arthur's recipe replaces baking powder, and its 2 : 1 : 1 proportions match the per-teaspoon swap (1/2 teaspoon cream of tartar, 1/4 teaspoon baking soda, 1/4 teaspoon starch for 1 teaspoon of baking powder).

Gram and ml equivalents per spoonful are our own conversions (grams derived from King Arthur's batch weights, ml from standard volume equivalents), not published figures. The batch weights (21 g, 14 g, 7 g) are King Arthur's.

Sodium is our own calculation, not a published figure. Baking soda has 27,400 mg sodium per 100 g and cream of tartar has 52 mg per 100 g (USDA FoodData Central, SR Legacy). The whole batch holds about 3,850 mg, so 1 teaspoon of mix (about 3.5 g) holds about 321 mg, or about 14% of the 2,300 mg FDA Daily Value. The starch is not counted.

Nutrition values are estimates calculated from typical USDA FoodData Central values, with tapioca starch as the starch. The figures are small because a serving is one teaspoon of dry mix.