What causes blotchy icing?
Blotchy icing is a phenomena that occurs after the icing is dried and could be caused by several things. Here are some things to consider. First, did any oil come in contact with the icing? This could cause your icing to separate. Second, occasionally oil from the cookies leeches up into the icing. Putting on very thin coat of royal icing — a glaze coat — and letting it dry before adding the icing may help to seal the icing. Third, did you use more food coloring than you needed? Dark colors are more prone to this than other colors and we suspect that this may be an issue. See “How to Make Red Icing” above. Fourth, was your flow icing thin enough to flow but not too thin? Too much liquid may be a factor. Finally, humidity affects icing. Try to keep your cookies in a cool dry place while they are drying. Hope this helps.
