Homemade Baking Powder (One Less Thing to Buy)

Baking powder is one of those things that always seems to run out at the worst time, mid-recipe, no store nearby, batter already mixed. That happened to me one too many times before I actually looked into what baking powder even is. Turns out it’s just baking soda and an acid, nothing that needed a factory or a specialty aisle.

Now I don’t buy it anymore. Two ingredients, a couple minutes, and I have exactly as much as I need, made fresh instead of sitting in a canister losing potency for who knows how long.

Homemade baking powder in a nutshell: Combine 1 part baking soda with 2 parts cream of tartar, plus 1 part cornstarch or arrowroot if you want it shelf-stable rather than used immediately. Mix well and store airtight. That’s the whole recipe, and it works exactly like store-bought in any recipe that calls for it.

Why Make This Instead of Buying It

Most store-bought baking powder includes added starches and stabilizers to keep it shelf-stable for years on a store shelf, along with, in some brands, sodium aluminum sulfate, which is where that faint metallic aftertaste some people notice comes from. None of that’s dangerous in normal amounts, but it’s also not necessary if you’re making a fresh batch as you need it.

Beyond ingredients, it’s one less specialty can taking up pantry space for something you can make from staples you’re probably already storing anyway. If you’re working with limited storage, that adds up the same way it does with brown sugar or any other single-purpose canister sitting mostly empty in the back of a cabinet.

The One Thing Most Recipes Don’t Tell You

Homemade baking powder is single-acting, it reacts once, as soon as it hits liquid. Store-bought is usually double-acting, meaning it reacts once when it gets wet and again when it hits heat in the oven, which gives you more forgiveness if your batter sits around before baking.

With the homemade version, get your batter or dough into the oven soon after mixing. The reaction starts working immediately, and letting it sit too long means you lose some of that rise before it ever hits the heat.

The Recipe

That’s the entire process. If you go through baking powder quickly, you can skip the cornstarch entirely and just mix a small batch fresh each time.

How to Tell If It’s Still Good

Baking powder loses potency over time, homemade or store-bought. To test it: drop 1/2 teaspoon into a small cup of hot water. Immediate bubbling and fizzing means it’s still active. Nothing happening means it’s time for a new batch.

Storage

• Without cornstarch: about 1 month in an airtight container before potency starts dropping
• With cornstarch or arrowroot: up to 6 months in a cool, dry pantry
• Keep the container tightly sealed, moisture is what kills it fastest

If you’re stocking a pantry meant to last months rather than weeks, here’s how much food to actually plan for, baking powder included.

If you like the idea of a pantry built on staples instead of single-use canisters, I put together a free guide on building exactly that. It’s called the From-Scratch Pantry Starter Guide, grab it below.

Frequently Asked Questions

Can I make this without cream of tartar? Not exactly, cream of tartar is the acid that actually activates the baking soda. Without it, you just have baking soda. Lemon juice or vinegar can work as an acid directly in a recipe, but that changes the recipe itself rather than giving you a shelf-stable powder to keep on hand.

Is homemade baking powder aluminum-free? Yes, this recipe has no aluminum, unlike some commercial brands.

Can I use arrowroot instead of cornstarch? Yes, 1-for-1, and it’s a good option if you’d rather avoid corn-based products.

Is this gluten-free? Yes, baking soda, cream of tartar, and cornstarch or arrowroot are all naturally gluten-free.

Can I make a big batch for long-term storage? Yes, but include the cornstarch or arrowroot if you’re not using it within a few weeks, without it the mixture clumps and loses effectiveness faster. For true long-term storage, some people keep the ingredients separate and mix a fresh batch as needed instead.

Final Thoughts

This one’s not glamorous, but it’s exactly the kind of small thing that adds up: one less can in the pantry, one less ingredient that goes stale before you use it all, one less thing standing between you and whatever you’re actually trying to bake. If you liked simplifying this one, Cream of Anything Soup is another pantry staple worth making the same way.

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