I sold cupcakes at the farmer's market in town today and my vanilla buttercream frosting was dyed purple using wilton's violet gel color. However, by the end of the afternoon they had turned blue??? It was a pretty blue but I'm just wondering what happened in case a customer wants an order with purple frosting, I don't want it to randomly change colors. It was quite hot out today too with a heat index of about 100 degrees and tons of humidity, YUCK! Any ideas??

No helpful ideas sorry, but just to let you know, I think it might be normal...?

I was talking to the lady who owns the cake shop I buy from about purple colours. She said she avoided purple if at all possible, because it always fades very quickly.

This discussion came after I was looking at some purple fondant the week before, and couldn't find it the next week. Turns out it WAS in the basket I was rifling through, it had just faded so much that it was unrecognisable.

I wonder if adding a bit of red to it would help? You might have to experiment, make it purple, then add some red, and wait all day and see what happens to it. The theory being that maybe the red will pick up the slack once the purple fades....?

It's normal for the purple to change to blue. But I've heard if you use milk in your buttercream the colour may hold better. I have used the Americolor purple and had decent results with that.

That sounds like a nice experiment zespri. If anyone tries it out, or has already, I'd like to know if it works!

I have had the best results using violet from Americolor, or mixing pink with blue. It's the red that fades apparent;y so ever since i stopped using that it has helped!

I just did cupcakes and a cake with purple buttercream and used violet, i kept them in a dark closet until i brought them to the party and they were fine. I did notice the last couple cupcakes i had leftover that sat out in the kitchen turned slightly blue- when i bit the frosting i saw it was deeper purple inside. That reminds me there is one left and I am going to go eat it before someone else does!!

Purple fades in sunlight and fluorescent light. IndyDebi has posted some great info about the subject of the fading.

I've been experimenting with Crystal Color's purple this week. I've had a piece of purple fondant in a window sill under fluorescent lights for about a week with no color change.