It should have been perfect. A 6 inch white birthday cake. 4 layers, fully/correctly cooked, domes sliced off. It was encased in a correct Italian buttercream (sugar cooked to 248°F) with a strawberry "jam" layer that was set with agar powder. The cake itself was pretty even (squared off), at least on the outside I served it at a party in a kitchen that might have been as warm as 85 degrees (lots of people, no AC), but I don't think anything melted. The cake was tall, but not excessively so.

We cut a few slices, and then when I turned around the upper disks of cake fell off!

  • Does a 4 layer cake need dowels then? And then be cut by someone who knows what they're doing?
  • Or is heat actually to blame?
  • Did it still taste okay after the collapse ?
    – Criggie
    Sep 10, 2023 at 19:36
  • 2
    Agar agar sets around 35-40C and melts again at 80-90C so if "85 degrees" is Centigrade and not Fahrenheit then the heat may have contributed
    – postmortes
    Sep 10, 2023 at 20:27
  • 19
    @postmortes : if it was 85°C, they wouldn’t have noticed, as they’d be dead (185°F).
    – Joe
    Sep 10, 2023 at 23:36
  • 1
    @Joe oops! My bad, I misread it as the cake being a hot part of the kitchen! Still, I guess I should have realised at 85C that would mean an oven or so... :-/
    – postmortes
    Sep 11, 2023 at 6:56
  • "6 inch birthday cake" means what, here? - 6 inch diameter and 4 layers tall seems likely to be unstable, unless the layers were quite thin. 6 inches thick (so roughly 1-1/2" layers, including jam?) If so, how big horizontally?
    – Ecnerwal
    Sep 12, 2023 at 3:01

2 Answers 2


I’ve had this happen because I :

  1. Did not use dowels
  2. Put too much pudding in between the layers
  3. Had put the cake on a non-level table

The cake started ejecting the upper layer (there were only two) of the cake, especially when the slices had already been cut.

It’s possible that you had something similar happen with your jam layer, and a warm day would make it more likely to loosen up and flow better. If your cake layers were domed and hasn’t been leveled, that could also explain why it didn’t happen until after you cut the cake.


When I do 4 layers, I double barrel it and put a center dowel just to make sure it's as stable as can be. I always keep them refrigerated until about an hour before it will served. That always has worked for me.

  • 1
    What do you mean by "double barrel"? I haven't seen the phrase before in a cake context.
    – rumtscho
    Sep 14, 2023 at 18:56

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