Help! I can't seem to make my Swiss Meringue Buttercream blue. Since after i've added all the butter, the SMB's color would be yellowish, adding the color blue makes the SMB greenish instead of blue. Should I add another color? should i use another color instead of blue that would result to a blue SMB? Appreciate your expert advise.
My suggestion would be to try to get hold of some butter that doesn't have the yellow food coloring in it. Untinted butter is practically white and I know you can get it, although sorry to say I don't know exactly where. I don't think there's any way to counteract the blue-yellow combination: there is nothing that you can add to yellow to make blue, since blue is a primary color.
Try adding a bit of violet. Also, candy colors work well in meringue buttercreams, and they are also a bit stronger.
I use Swiss pretty much all the time and blue is a little tricky. If you are using a light blue gel color, it does start out as a greenish blue but eventually it gets to blue. Next time I have thought about starting out using royal blue to speed it up but use less gel. AnnieCahill is right about a tiny bit of violet would perk up blue too.
Another thing you may want to look into is your brand of butter. Not all butters are created equally so your brand may be yellower than others. I use James Farm, Cabot and Plugra.