I have made this banana bread recipe a couple of times. The ingredients are:

  • All-purpose flour
  • Salt
  • Brown sugar
  • Baking soda
  • Bananas
  • Butter
  • Eggs

My understanding is that baking soda requires some acid such as milk or yogurt to provide leavening. But this recipe doesn't call for anything that is an acid that I can see. Yet it does produce a perfectly edible loaf and not a dense brick.

What is reacting with the baking soda to provide leavening?

  • Getting an actual brick is harder than people think, especially if there is water (from the bananas) in the recipe - and even if not, that recipe would probably yield something shortbread like and not inedible. Commented Feb 28, 2017 at 11:33
  • @rackandboneman Challenge accepted 😀
    – verbose
    Commented Feb 28, 2017 at 20:23

3 Answers 3


Most of the ingredients in this recipe are acidic.

ph values:

  • flour 5.5-6.5
  • brown sugar slightly acidic
  • bananas 4.5-5.2
  • butter 6.1-6.4

The salt is neutral and the eggs are not acidic, ph 7.1-7.9

The combination of these ingredients is acidic enough to interact with the baking soda to leaven the bread.

Even without the bananas, there would be some leavening. Consider the standard ingredients in chocolate chip cookies: flour, sugar, butter, eggs, salt, baking soda and chocolate chips. Though they don't raise nearly as much as banana bread, they do poof up a bit.

  • chocolate chip cookies puff because you beat air into the butter while creaming it and that air expands as i warms. this is not the case with banana bread
    – Agos
    Commented Mar 2, 2017 at 9:01

The banana does. Bananas have a pH level of 4-5 making them more acidic than milk.


This depends on the banana that you are using there. You need to check if its ripe or unripe because unripe ones are little more acidic than the other. To be specific unripe bananas have a pH of around 5.6 and ripe one has a pH of 6.5

  • 2
    All of your answers have linked to this site. Are you affiliated with it?
    – Cascabel
    Commented May 9, 2017 at 15:09

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