Learning new things all the time about: chemistry

May 19, 2023 12:19 PM

How to DIY baking powder so it measures the same as store-bought? Turns out it loses strength over time, so I want to make my own as needed. Recipes say 25% corn starch is "optional".

Optional is fine, but which is going to give the same rise as say, Calumet? Without corn starch/arrowroot/whatever which will essentially be more baking soda per teaspoon baking powder, or with?

I am aware that commercially produced baking powder is likely to include a starch, but not how much.

BTW - in case "baking soda expires" is news to you, here was my clue: same biscuit recipe as always, but flatter than I expected. I knew the flour was good, but a friend explained about old baking powder.

posted by amtho to Food & Drink (7 answers total)

I think the only way to know is to experiment- especially if you've been using Calumet. Calumet's ingredients are: Baking Soda ( For Leavening ) , Cornstarch ( Maintains Leavening ) , Sodium Aluminum Sulfate ( For Leavening ) , Calcium Sulfate ( Maintains Leavening ) , Monocalcium Phosphate ( For Leavening ) .

That means the online recipes for baking powder are not going to replicate Calumet exactly- or any double-acting baking powder. I would definitely keep the corn starch in those recipes (unless you have a sensitivity) though- it helps the bubbles that are produced remain stable.

You should also test your baking powder before using because it can expire as well. Ways to test both baking powder and baking soda for potency are in this article from the Kitchn.
posted by oneirodynia at 2:03 PM on May 19, 2023

Ingredients on labels are always listed by largest percentage first. As a single ingredient baking soda is the largest percentage of Calumet, and cornstarch the second. However everything that follows are different types of acids. So the recipes for homemade baking powder that are 1 part baking soda, 1 park cornstarch and 2 parts cream of tartar are probably a decent place to start. Again though, they won't be double-acting because they only contain one type of acid.
posted by oneirodynia at 2:09 PM on May 19, 2023

Response by poster: I don't care about Calument per se - just creating the amount of rise than recipe authors intend. And I'd prefer not to have to take time to do experiments, but... nobody else is answering yet....

If there's a "duplicate this commercial baking powder" recipe, that would be cool.

Thank you!
posted by amtho at 2:21 PM on May 19, 2023

Home made baking powder is 2:1:1, cream of tartar: baking soda : cornstarch. So if you need a teaspoon of baking powder, it's 1/2 tsp cream of tartar, and 1/4 tsp each of baking soda and cornstarch. It works for me but I can't say I've tested it, exactly.
posted by blnkfrnk at 5:18 PM on May 19, 2023 [1 favorite]

Ha, I just went to write down that ^ formula in my old Joy of Cooking (1983, in case science has changed since then) and turns out, they anticipated me. The formula they give is: 1 tsp baking powder = 1/2 tsp cream of tartar, 1/3 tsp bicarbonate of soda, and 1/8 tsp salt and “do not delay putting batter in oven” and then they go into a lot more detail about chemistry.
posted by TWinbrook8 at 7:43 AM on May 20, 2023 [1 favorite]

Bicarbonate of soda also loses potency when stored separately. If you bake rarely enough, you still need to rebuy.

Alternative strategy: protect your baking powder more (really airtight in the freezer, eg).
posted by clew at 8:40 AM on May 20, 2023 [1 favorite]

I make my own baking powder. From what I've read, the cornstarch is to stop caking of the baking power. I don't add salt - it's just baking soda and cream of tartar.
posted by bluesky43 at 3:10 PM on May 20, 2023