I have 5 gallons of fresh pressed cider fermenting. I would like to add cherry to the wine to make an apple/cherry mix. Could I add a frozen concentrate something like this: http://www.walmart.com/ip/Old-Orchard-100-Juice-Apple-Cherry-Concentrate-Frozen-12-oz/10805178 and when would I add it? I have some room in my carboy that I should probably top off next time I rack (it will be my 2nd racking). Thanks!