I have a 4 tier wedding cake with 2 of the tiers having large grain (crystal) sugar pressed into the icing, can these tiers go in the fridge? will the sugar 'melt' if the cake sweats when i take it out?

Thanks for your help.

I've found that some brands of crystal sugar can hold up, others not so much. (This goes for both baking and decorating.) Can you experiment? Spread buttercream on something, sprinkle with your sugar, and place in fridge. Take out the next day and see what happens.