Don't freeze it!
I keep mine for a couple of weeks at room temp, just make sure it's well sealed so it doesn't dry out. I think you can keep it up to a month without problems, I usually use mine up before it's around that long though.
You can search for other posts on this, seems like it was discussed fairly recently.
hth!
Laura.
Royal Icing.
For more information on this recipe and what you can do with it on cookies, check out Antonia74's tutorial on the articles page, titled "How to bake & decorate cookies".
Laura.
I keep mine in a well sealed container, marked with the date on it. The most I have kept it was 2 weeks, only because I used it. As long as it is sealed properly and at room temp, you should be fine.
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