The Big Bang Theory

Are you generally careful with your cakes when you remove them from the oven? Do you gently set them on a cooling rack to settle in? Then what I have to say may come as a shock to you. Coddling your cakes may actually undermine their structure and a bit more tough love may give you the results that you actually want.A-2banger-webThe two cakes above were baked from the same batter and cooked to the same degree of doneness. In the above photo, the cake on the left shrunk in considerably from the sides (about 1/2 inch), wrinkled up on the top and became somewhat concave.  The cake on the right shrunk in less than 1/4 of an inch and maintained a nice even, level top.  So what’s the difference? The cake on the right I thwacked firmly on the counter upon removal from the oven, the cake on the left I placed directly on the cooling rack.


While this seems to make counterintuitive sense there is actually some valid science behind this “big bang” theory.  Here is how it works:

  • As your cake bakes, trapped gasses expand and liquids vaporize to create pockets of “air”.
  • When the batter solidifies, proteins and starches form walls around the gasses and create individual cells.
  • When the cake is removed from the oven the gas cells shrink as the temperature drops (according to the formula PV=nRT).
  • If the individual cells remain intact, gas contraction occurs at varying rates and can lead to a sunken, shrunken cake.
  • If you give the cake a good pounding, it essentially pops the small cells creating one uniform cavern of gas that can cool and shrink more consistently throughout the cake.

I know it seems a little scary to whack a delicate cake, but I have been doing this for years now and have never had it destroy a cake’s structure.  This technique will not fix every sunken cake problem. There are times when a cake is not properly formulated and no amount of banging will help. But there are times when this method gives just enough edge to make a difference in the final structure.

So, get your frustrations out and give your cake a good knock-upside-the-pan. You may be very pleased with the results.

Happy baking!



35 thoughts on “The Big Bang Theory”

    1. I don’t actually “thwack”….but I do take a clean tea towel, lay it over the cake & tin. With oven mitts on I gently push down the cake all around the sides and centre. Then let cake cool. Think this achieves the same purpose.

      1. Yes, I think that would achieve the same end. On some fragile cakes that may cause them to collapse but sturdier ones would fare well. 🙂

  1. Lol, love the “science” behind your explanations. I may not always understand it, but I still love how deep and thorough you are. Thanks!

  2. Yes, I have been using this method to release gas bubbles too. But I find it less effective on my chocolate chiffon cakes. Other cakes are fine

    1. Yes, it makes more of a difference on some cakes than others. This was a very light, fluffy cake and showed a more dramatic difference.

    1. Thwacking before will help to dislodge large air pockets that are trapped so that is helpful too. Who knew you had to beat your cake up so much! 🙂

  3. I’ve just discovered your site and signed up – I trued this with my cake last night and it even works in Australia!! Thank you for your great advice – I’m going to try your coconut cake tomorrow.
    happy cooking

  4. Wow! This is SO interesting! I hated science in school, but I find that I am actually looking up all your “science projects”! Somehow now it makes scense! Hahaha! I knew about knocking out the big airbubbles before you put the cake in the oven, but not about this bullying afterwards! Hiehie….even more reason for me to bake when I’m upset! I find baking calms me down, so I bake ALOT!!! Hahaha!

    I look forward to what is next……!!!

    1. Hi Mariette, Baking calms me too. Which is funny because cooking stresses me out 😉 Cake is such a complex subject that I am always curious about something new. I will have more up soon but am just back and recovering from my high school reunion. I don’t have the stamina I did back then! 🙂

  5. Do you mean you bang the bottom of cake pan down on the counter and then put it on a cooling rack for a while before removing it from the tin? Or do you mean you bang the cake pan against the counter so the cake comes out straight away?

    1. Bang and then cool in pan until the cake has firmed up enough to remove it. This will matter more in some cakes than others. The cake I made was very light and fluffy so it needed a little while for the starches to settle before I turned it out. 🙂

  6. Should you thwack all cakes? I am looking at your sitr, and would like to make some. I have followed another site where it was recommended to not spray the sides of the pan in order to get flat layers.

  7. Definitely a thwacker of note. Have NO time to be gentle so it’s grab and plonk and plonk again and move out of the way for next lot and leave. I have beautiful cakes. THANK U Summer, you’re a thinker!!!

  8. hello Summer,
    sorry to ask again about that method…did you by any chance take a recording of that move for us…at least for me. I have no idea how to handle that smack to my cake? …. and nothing about it on Youtube…
    thank you so much.

  9. Hello , I love your site. Do you happen to know other reasons why this may happen? I just took a cake out of the oven that I tried a reverse creaming method with and it shrunk similar, maybe more to the ‘unthwacked’ cake pictured above. I am trying to figure out why. Any help would be greatly appreciated. Thank you

    1. One of the features of reverse creaming is that it really costs the gluten forming proteins with fat before they have access to water which converts them to gluten. It may be that the reverse method over-tenderized your cake and left it too weak to stand up to itself, this the shrinking. I hope that helps a bit! Best baking to you. 🙂

  10. OMG! I remember reading about banging cake pans on the counter after baking when I was still starting out with cakes. I’ve been having trouble with shrinking these past few weeks so I tried searching about it again but I literally cannot find anything about thwacking the cake pan after coming out of the oven. So glad I came across your article confirming that it is indeed a thing.

    1. I’m so glad this could help Jess! It’s kind of a funny thing, it seems counterintuitive, but it really does make a difference. I’ve become so accustomed to doing it, that it feels strange not to bang a cake on the counter when it comes out of the oven.

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