Welcome to the Cake Decorators Q&A
Hi can someone advice please
The buttercream is soft under my sugarpaste
If I put it in the fridge it will sweat
And now I have a big air bulge 😡😠
Unfortunately, placing the cake in the fridge will only exacerbate the problem. As soon as the cake hits room temperature, the icing will sweat even more from condensation and take a long time to dry out.
Here is a past answer which may make more clear why this has happened:
It appears the buttercream was not stiff enough to cope with the humidity which you are experiencing. It may also be that the layers have been overfilled and the filling is now spilling out to make the bulge. I can only suggest removing the sugar paste and repairing the internal structure of the cake with stiffer buttercream or with strong ganache.
Before filling, pipe a dam of stiff buttercream/ganache about a quarter of an inch in from the edge of the cake layer. Let this set up before filling. Don't overfill 🙂 Once the layers are filled and stacked, let the cake settle either under its own weigh or weight it down with a plate, to expel any trapped air between the layers. Let it sit for a couple of hours before re-icing. (if using a plate, place a cirlce of parchment paper on the top layer of the cake to prevent plate sticking)
Please let me know if this helps or if you need more information.
Thanks for your reply
My buttercream had shortening in as well as butter so don't think it was too soft.
I'm going to try the buttercream with ganache as Paul recommends.