Colored Icing Dries Differently Than White

You might be overmixing when adding in your colors. That happened to me with a set once--I was having trouble getting the color right and I had to keep adding color and mixing, mixing, mixing. That color dried funny--a little crumbly, like you said.

Thank you. I did hand mix a lot to achieve the right color. How else can you get the right color besides hand mixing? Especial the colors that are more labor intensive. Should I remix with the kitchenaid mixer? Any tips?

I mix almost all my colors by hand, too, but I just try to get the color right quicker. Easier said than done, I know. If I have a big amount of icing to color, I'll just mix it up with my KA, which makes it a ton easier and quicker. 

Are you using gels or liquid colors? I agree with Lucky Penny though...it sounds like you might have added a lot of color to get the shade you wanted...catch 22.

I use the Wilton gel color. I guess I need to mix the color in with my KA and not by hand? This happened with a color that I had to mix more than 1 color in so there was a lot of hand mixing. Maroon, Dark Blue and Black.

This happens to me.  I believe it is due to the humidity.  

I suspect the electric mixer will mix it much more than hand mixing, and I doubt hand mixing is the problem. Almost everyone I know mixes by hand, and some people think over-mixing causes the problem. I have noticed white gel food coloring will thicken my royal icing a bit, and wonder if you use it in white icing and/or colors? It's worth looking over the Icing issues topic in the forums here, as this seems to be a common problem.