I guess whether you can taste the CB depends on how sensitive your palate is.
I have one color (princess pink by CR) that has a distinct 'off' smell. It does have white mixed in it, and when I use it on bonbons, the bright pink color actually fades after a few days. Very strange.
I still chisel CB out of the bottles and only heat a little more than the amount I'll be using. I recently transferred each color to its own little container and am embarrassed to say how many colors there were (and how many containers I needed!), so I *really* hope they last a good long while!