I was making some banana bread. I didn't have any self-raising flour so made my own by adding baking powder (BP).

An unfortunate senior moment saw me add the BP to the wet ingredients instead of into the flour...sigh...

I figured it would still work. After all, the BP is just another ingredient, right?

The final result tastes great, but it didn't rise at all. I don't understand why that would happen, can someone explain why the BP should be added to the flour?

  • 3
    Was the baking powder still in date or had it been sitting at the back of a cupboard for years? It could simply have expired, with the wet/dry thing a red herring.
    – dbmag9
    Oct 4, 2022 at 7:16
  • 1
    How much BP did you use (grams or teaspoons)? And what about how many eggs and flour did the recipe have? Maybe it was not enough. I never use self-raising flour. I always use BP unless the recipe asks for yeast (in which case I add dry yeast, sometimes fresh). Have never had this problem before! So maybe it was not enough? If the taste was good, you definitely didn't put too much. You would notice a kind of metallic/weird flavor!
    – M.K
    Oct 4, 2022 at 15:07
  • What were the wet ingredients? Baking soda is alkaline and reacts with at least many acidic substances. Oct 6, 2022 at 9:01

3 Answers 3


First, I would point out that it actually did work. You say

The final result tastes great

Have you ever forgotten the baking powder in a cake completely? It doesn't taste great; it is a stodgy lump, wet and "unbaked". It is nowhere near "great", almost inedible. The baking powder probably worked, and the banana bread was properly leavened, just without reaching some spectacular extra volume.

So here are a few possibilities for your observation of a reduced effect:

  1. Mixing. It is easier to mix baking powder with flour than with a thick liquid. If it stayed localized in a single clump, the rest won't have risen.

  2. Timing. Baking powder relies on a chemical reaction which produces bubbles. The gluten in the batter doesn't let these bubbles rise up and disappear right away. This is why you don't want the reaction to start before the flour is in the batter. If you first mixed the wet ingredients, and they stayed around a bit before adding the flour, you may have spent the baking powder. This is especially problematic if it isn't double-acting (most current ones are, but there are retro, tartarate and organic brands which aren't). The same thing can happen if you let the batter rest for a long time before baking.

  3. If you had another mishap and used baking soda in a recipe intended for baking powder.

  4. Proportion. This may be simply due to the proportion of baking powder you used. If you normally use self-raising flour, you may have miscalculated the amount needed.

  • Thanks for your response, but I can safely say "none of the above". Maybe I just didn't add enough.
    – Steve
    Oct 4, 2022 at 12:01
  • 1
    @Steve point 4 was meant to say "didn't add enough". Apparently I had structured it so badly that it didn't come across, so now I reordered the answer. Also, you usually cannot know when it is caused by mixing, since it isn't visually clear if it is mixed well.
    – rumtscho
    Oct 4, 2022 at 12:52
  • 4
    @Steve Did you do everything extremely quickly after adding the baking powder to the wet, and also without mixing rapidly and potentially releasing some tiny invisible bubbles of gas? Spending a chunk of the first of the two times the baking powder activates is pretty easy to do.
    – Cascabel
    Oct 4, 2022 at 15:01
  • 5
    @Steve Re-examine point 2. Having the fizz escape because the wet ingredients weren't thick enough to capture the gasses seems most likely to me, as well. Extra mixing may have exacerbated the problem by breaking up any bubbles that were captured. Oct 4, 2022 at 20:24
  • @Steve adding on to rumtscho's answer, the acid(s) and base(s) in dry baking powder do not react together or with other dry ingredients until hydrated. If mixing with wet ingredients, the baking powder will start reacting with itself and with any acidic wet ingredients right away. Re: proportion - self-rising flour is legally capped at 4.5 parts leavener per 100 parts flour by weight, so a max ~1 tsp per ~1cup flour. Oct 5, 2022 at 5:33

You can add baking powder or baking soda anytime before baking, it's just most convenient to add it to the dry ingredients as is mixes best that way. I've added leavening agents to batter for the same reason as you and it's never been an issue as long as it was mixed in thoroughly, which doesn't take that long.

You didn't get a rise because something else went wrong, maybe you didn't add enough baking powder, maybe you added baking soda by mistake in which case there wouldn't be enough acidity to activate it, the oven temperature was wrong, or something else. If your bread tastes chemically then it's probably the second reason as you're tasting unreacted sodium bicarbonate.

  • Thanks. Definitely baking powder. Well mixed, especially after I realised my mistake. Maybe there was not enough.
    – Steve
    Oct 4, 2022 at 11:59

Thanks. Definitely baking powder. Well mixed, especially after I realised my mistake. Maybe there was not enough. – Steve

That could actually be the problem! When making a cake you don't want to overmix the wet and dry ingredients. That's why you're supposed to mix the dry ingredients thoroughly, add the wet, and just fold it together. If you keep mixing the batter, at some point you end up kneading instead of mixing, and gluten will form. Which will make the final result too dense. (Gluten is good in 'proper' bread, as it can maintain the structure during the prolonged rising and baking. But for a cake that rises quickly, with carbon dioxide bubbles from the baking powder (or -soda), you don't want that.)

Also, modern baking powder is 'double acting' and will release some gas when mixing with the water, and some when heating. You probably lost out on the first half.

  • Now I want to do some tests... how much banana bread can I make without driving the family crazy :D
    – Joe M
    Oct 5, 2022 at 18:11
  • 3
    Note that depending on your location double acting baking powder may not be as a common thing as in the us, like in germany you have to look quite hard for it.
    – PlasmaHH
    Oct 5, 2022 at 18:48

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