Baking soda by itself is a leavenerPosted: 6 September 2011
If you’ve ever read that baking soda is a leavener when you use it with buttermilk, vinegar, or something else that’s sour and assumed, like I did, that it won’t cause the bread to rise if you’re not using something sour, you’d be wrong. Even by itself it causes the bread to rise. I don’t know why. Perhaps it’s from the long rests that I always give my doughs; maybe that’s making the dough slightly sour (although I certainly can’t taste any sourness).
Update: according to Ideas in food by Aki Kamozawa and H. Alexander Talbot what’s happening is that the baking soda releases carbon dioxide when it’s heated.