I'm with Drewed, I take some fresh pressed apple cider and almost fill a gallon water jug, then freeze it. SOLID.
When I pull it out I set it upside down, either on my carboy stand, or just on top of a beer pitcher.
Monitor how much is melting. When I collect about half a gallon, I check the gravity. I have had it as high as 1.084.
I have used this for back sweetening, or just to bring up the OG on a different batch of cider.
The sugars and the apple essence are what seem to melt first, and you get rid of the excess water.