I made a cake for my friend's son and used yellow food gel to colour the buttercream and the fondant base. The fondant base turned out lemon yellow, which is the colour I was aiming for. The buttercream, however, ended up a pale orange colour!!! I have used the same food gel before on the same kind of buttercream (SMBC) and got a good result- a very yellow colour. All the ingredients were exactly the same including the same brand of butter (unsalted, if it makes any difference) so I cant think why this time round I got pale orange rather than yellow. I made sure I was using yellow food colour as well, in fact I had to keep checking the same bottle and I was definitely using yellow! 

The only other thing I can add is that I made the buttercream in the evening, and it did seem to have a very very pale orange tint to it even before I added to yellow colouring but I put it down to the lighting. Its pretty difficult making cakes during the day, as I have a 4 year old running around wanting to 'help' so I tend to do things in the evening.

Has this happened to anyone? Any ideas as to why this has happened to me?

they put food coloring into butter--maybe that batch of butter had more coloring in it than usual??

annatto

especially since you said the bc was orangey before you added the yellow color

It also takes a surprisingly small amount of yellow to color a batch of anything.  A full drop can take it from yellow to orange in an instant.

K8Memphis, hmm yes perhaps that may be the cause of it. 

Leah_s, I never knew that was even possible, but quite clearly as its happened to my SMBC, it is! Bummer.

I probably have to put it down to the butter. I think I need to look for a different brand!