Just found this thread - for a couple of years I have made ginger wine using locally-obtained grape must which is cheap and not great quality (used for making commercial mass-produced grape brandies). I would get 10L of the must and add another 10L of water and 7kg of sugar for sweetness, plus almost 2Kg of ginger and a few lemons and bananas and things, and it has turned out very nice, and I have had to make extra for friends etc.
The grape harvest failed big-time last year due to heavy rains, and my supplies of my favourite winter warmer are running low as I couldn't make it. I am thinking using raisins as a base would be just as good for this. I would also like to avoid using added sugars, and just produce alcohol from the raisins. "Ubermensch" back in 2008 mentioned "20 L batch ... with 5 kg of sultana raisins and no sugar" (that's about 11lb per 5 gallon batch) - others have given somewhat different numbers.
Any idea on what sort of ball park of ratios of raisins to water we need to be in to arrive at a "winey" sort of ABV - 11% or something?