AI seem to be having a problem with my smbc! I made it up yesterday according to the exact instructions of my recipe (same one I have made for months with no problem). I refrigerated it over night and brought it out a few hours ago to bring it to room temp. I stirred it a little bit with my spatula but now it has this unattractive clumpy look, almost curdled. It also seems to be weeping. I know I took care to not over mix, but I am afraid if I try to rewhip it will separate completely! I attempted to ice my first 6in tier and it barely sticks to the cake, sliding around when I pass over with the cake smoother and at points, completely sliding off the cake.

Sorry for the wordiness but idk what to do and would like to know any possible solutions or reasons just in case this happens again in the future!

AIt needs to be whipped again. That should fix all your problems.

If just whipping it doesn't help you can take 1/3 of the SMBC and pop it into the microwave for 10 seconds. Then add it back to the rest of the buttercream and whip again. Any time I have had it look curdled after refrigeration this method has worked really well for me. 

AThanks for your replies! I nuked it then rewhipped and its good as new. Idk I was just scared of reaching a separation point!

Thanks again:-D

AJust hold the mixing bowl with the SMBC in it, over the burner on your stove for 10 seconds. Let some of it melt, and put it back on mixer to whip. Keep doing that until it becomes creamy again.

It was probably still too cold. Another easy way - don't even have to take it out of the mixer -  Hold a blow dryer a foot away from the bowl while mixing on low.  Stop the blow dryer when you see it just starting to soften and come together and continue to whip up until it is smooth again.  

Thank you all for your generous tips and replies! I will definitely keep them in mind when I purchase my stand mixer. One bowl!!!

yortma,

Thanks for the hair dryer trick. It has to be easier than the hot towel I have used in the past.