Raisins have around 60g of sugar per 100g. To get to 11% AbV in 1 Gallon (~4L) of water you need 700g of sugar fermented dry. So if you add (700g / 0.6) = 1.17kg of raisins to 4l of water (volume will be more than one gallon because the raisins add volume) you end up with 11% AbV.
That's what I...