If you want to use gel color in cakes, there are a few things you need to know. First, gel color is much more concentrated than regular food coloring, so you need to use less of it. Second, it can be difficult to get gel color to mix evenly into batter or frosting, so you may want to use a toothpick or other small tool to help distribute the color. Finally, gel color can sometimes tint the food it touches, so be careful not to let it touch anything you don't want to be colored.
