I found this on the forum posted by Jonny69.
If you would rather make something much quicker have a read of this thread -
http://www.thehomebrewforum.co.uk/showthread.php?t=49462
Well folks, like it or not, it's coming up to blackberry season! This will be my third year making blackberry wine and last year's crop was amazing. Last night I opened a bottle I brewed last August and it was fantastic, so I thought I would share the recipe with you.
Method:
Put 2 kg blackberries into a clean bucket
Pour over 1.7 litres of boiling water and a mug of stewed black tea made with 2 teabags
Mash it to a pulp with a potato masher
Stir in 1 crushed Campden tablet, 1 teaspoon of pectolase, 1 teaspoon of yeast nutrient
Cover and wait 24 hours
After 24 hours, strain it through a sieve, pushing as much liquid out as you can with the back of a ladle. Then squeeze the pulp through a muslin into a demijohn to make sure you get as much juice out as you can. Add 1kg white sugar and 1 teaspoon of Young's wine yeast to the demijohn. Fit an airlock. After 12 hours it should be frothing up and brewing:
Once it calms down, maybe after a week, top it up to the neck with either red grape juice or apple juice. I did one with red grape and the other with sharp-tasting apples I'd scrumped off Isaac Newton's apple tree at work, which I think is the better of the two. Allow it to ferment out, which will take about month, then rack it off, shake out the fizz and let it clear by itself. Once cleared, I added half a teaspoon of sorbate and half a crushed Campden tablet to each gallon. I don't like to add too much.
Mine was drinkable almost immediately and I only managed to hold back 5 bottles, which I've been struggling to keep my hands off, but I opened one last night. It has changed slightly, you can taste a bit of age in it, so I think I will keep the remaining two bottles for next year to see how they turn out.
I would estimate it's about 14% and still slightly sweet. If you don't want it as strong, then reduce the amount of sugar to 800g.