I'm making a few batches of all butter buttercream and was thinking about mixing into some Sam's bc, will it need to be refrigerated?
I usually use a French Vanilla coffee creamer in my bc, should I use a powdered creamer mixed with water or will the liquid creamer be ok?
The times I've used a powdered creamer my bc turns gritty, so I don't know if that's it or not.
If your house is nice and cool, your all-butter BC will be fine at room temperature. I don't know about mixing it into Sam's BC - I don't eat or use that stuff - blech.
Liquid coffee creamer would be best unless you dissolve the powdered creamer in another liquid...but when making BC using all butter, you generally don't have much (if any) liquid added to the recipe. Perhaps just use a teaspoon or two of high-quality extract, or else your BC may be too soft/thin.