@Julia M. Usher posted:Hi, Nika. The stability of royal icing depends on how thick it is mixed and your exact recipe (for instance, some meringue powder has additional gums and starch that stabilize it; and, the thicker the icing is mixed to start, the longer it takes to separate). Why don't you do a test run with your icing? Just mix and bag it, and watch how long it takes to separate.
In any scenario, I would ship it such that it's no more than a few days in the mail. And if it is bagged, she can always knead it in the bag to re-homogenize it.
Thank you. I made several tests already and it always starts to separate next day lastest.
It works with kneading, but it desnt look nice when you get such separated royal icing 