Baking powder substitutes, and exactly how much of each

Baking powder is baking soda with its acid already mixed in, so the swap is to add the two separately: 1/4 teaspoon of soda for each teaspoon of baking powder, and an acid for it to react with. Cream of tartar is the closest match. Buttermilk, soured milk and lemon juice work too, and they are not equally strong.

Why baking soda needs an acid

Baking powder is three things in one tub: baking soda, a dry acid, and a little cornstarch to keep the two dry and apart until they meet water (The Bake School). Once wet, the soda and the acid react, and the carbon dioxide they give off is what lifts the batter.

Baking soda on its own is three to four times as strong as baking powder, but it has nothing to react with (Arm & Hammer). Every swap on this page is the same repair: a quarter as much soda, plus something sour.

Why a baking powder swap can taste soapy

Soda that finds no acid does not simply go to waste. It breaks down in the heat of the oven instead, giving about half the gas it would have given with an acid, and it leaves behind a residue that turns a pale crumb yellow-brown and makes it smell of soda (Chemistry of Cooking). Arm & Hammer calls the taste bitter or soapy. So the real question with any of these swaps is how much of the soda its acid actually uses up. Often less than you would guess:

These are our estimates. They come from USDA’s spoon weights, the neutralising values the American Society of Baking gives for cream of tartar and for buttermilk’s lactic acid, lemon juice at 1.44 g of citric acid per fluid ounce, white vinegar at its labelled 5% and buttermilk at about 0.8% acid, the figure an Oregon State bulletin gives. Spoonfuls and brands vary. Three things follow.

Most recipes finish the job themselves. Brown sugar, honey, maple syrup, natural cocoa, yogurt and sour cream all react with soda (King Arthur Baking), so a batter with any of them in it mops up what the swap leaves over. That is why the printed ratios work as well as they do.

A plain batter shows it. A vanilla sponge or a basic muffin made with milk and white sugar has no acid of its own. For those, use buttermilk, or 5/8 teaspoon of cream of tartar for each teaspoon of baking powder, which is the figure Colorado State’s extension service prints. Using up all of the soda would take a scant 7/8 teaspoon.

Lemon juice on its own is the weakest. Half a teaspoon, the amount King Arthur and Clabber Girl print, uses up about a seventh of the soda. The calculator uses Arm & Hammer’s full teaspoon instead, and even that is best kept for a batter with brown sugar, honey or cocoa in it. Where the recipe has milk, the soured milk row gets more out of the same lemon.

Can you use bicarbonate of soda instead of baking powder?

Yes, with an acid. Bicarbonate of soda is the British name for baking soda: the same sodium bicarbonate, often shortened to bicarb. On its own it will not do, for the reason above, so use it exactly as the calculator uses baking soda, with one of the four acids.

A British recipe will also say plain flour where an American one says all-purpose, and self-raising flour for self-rising. The amounts carry across: 1/2 cup is 120 ml, and a teaspoon is 5 ml.

Self-rising flour instead of baking powder

Self-rising flour has the baking powder already in it, so it stands in for the flour and the powder together. By the home versions the Colorado State and Texas A&M extension services give, each cup carries 1 1/4 to 1 1/2 teaspoons of baking powder and 1/4 teaspoon of salt. Use it cup for cup in place of the all-purpose flour, and leave out the recipe’s baking powder and salt.

British self-raising flour is the same idea without the salt. McDougalls, Carr’s and M&S list only flour and raising agents, so with a British bag, keep the recipe’s salt in.

It suits recipes that ask for about that much baking powder per cup of flour: American biscuits, scones, pancakes and most muffins. Cookie recipes usually ask for much less, and self-rising flour turns them cakey.

Baking powder instead of baking soda

The swap runs the other way too, at three times the amount: 1 tablespoon of baking powder for each teaspoon of baking soda, the figure King Arthur, Arm & Hammer and Clabber Girl all give.

It is a less even trade. The soda was in the recipe partly to balance its acid, the buttermilk or the brown sugar, and without it the bake tastes sharper and can rise a little less. That much powder can also taste bitter or metallic. Cornell’s extension service suggests cutting the salt, and swapping acidic liquids for plain ones where the recipe allows.

Baking soda substitutes covers that direction in full: an amount table, what changes in cookies and cakes, and the low-sodium swap.

Is your baking powder still good?

Stir 1 teaspoon into 1/3 cup (80 ml) of warm water. If it bubbles straight away, it is fine. Clabber Girl gives an unopened tin up to 18 months and an opened one about six.

Baking soda needs an acid to show it is still active: a little in vinegar or lemon juice should bubble hard, by Clabber Girl’s test. And to tell the two apart in an unlabelled jar, put a teaspoon in a tablespoon of water. Baking powder fizzes and baking soda does not, which is King Arthur’s check.

Making baking powder to keep

King Arthur’s version of the swap adds cornstarch, which keeps a stored batch dry: 1/4 teaspoon of baking soda, 1/2 teaspoon of cream of tartar and 1/4 teaspoon of cornstarch (cornflour in the UK) make exactly 1 teaspoon, and replace 1 teaspoon of baking powder. So a jar is simple: 1 tablespoon of soda, 2 tablespoons of cream of tartar and 1 tablespoon of cornstarch, measured spoon for spoon like baking powder and kept airtight.

It does not behave like the tub you bought. Most shop baking powder is double-acting and holds part of its lift back for the oven. Homemade is single-acting: more than 70% of it reacts within minutes of getting wet, by The Bake School’s account, and nothing is held back. Mix the batter last and bake it at once. A make-ahead pancake batter or a dough chilled overnight needs the real thing.

How much sodium each swap adds

A teaspoon of double-acting baking powder made with sodium aluminium sulphate, the kind in several of the big American brands, carries 488 mg of sodium: about a fifth of the 2,300 mg Daily Value on a US nutrition label. Spread across a batch of muffins that is modest per muffin, but the swaps are not all equal, and if you cook for someone on a low-sodium diet it is worth knowing which is which. Per teaspoon of baking powder replaced, by USDA figures:

So the homemade swap carries about a third less sodium than that kind of powder. Buttermilk gives most of that back, because it is saltier than the milk it replaces: about 129 mg more per half cup. Low-sodium baking powder takes nearly all of it out by using potassium instead, 505 mg a teaspoon, which matters if you have been told to limit potassium. Cream of tartar brings potassium too, about 248 mg in half a teaspoon.

Self-rising flour, for comparison, carries about 1,490 mg of sodium a cup, from the salt and the leavening mixed into it. All of these are estimates from USDA’s figures for American products. A British tub or bag will differ, so its label is the better guide.