I used the lees from a batch of blackberry. Everything that was left when I siphoned to the secondary. Just started the s.p. on top of the lees and didn't have to clean out the primary first. Gives a light blackberry taste to the s.p. If you would like more blackberry flavor I would probably add fresh blackberries like you suggested. If you have the extra jam and swmbo doesn't object you could probably use that instead. Good luck with it, Arne.
I just made Blackcherry SP . I a gallon of Skeeter pee added one and a half cups of sugar and one package of black cherry Kool-Aid mixed it up left it sit for a couple of days till it all Blended together fabulous sweet flavor. Bih hit with the non-wine drinkers.
I recently finished making my second 6 gallon batch of skeeter pee, my son asked for some raspberry skeeter pee. I happened to have 2 bottles of Island Mist Black Raspberry Merlot left and tried mixing it in. Tasted so great that I used both bottles of Black Raspberry to 3 gallons of the skeeter pee and we have a new family favorite. Now to name it. Its unofficial name is my bloody skeeter pee.