Hi curry,
Blackberries are very good for winemaking, but are quite high in acidity so if you have a home brew shop near you try & get some acid reducing powder which will help. The other way around this problem is to make medium sweet or a full bodied port style wine.
For the first one use 4lb blackberries, washed & placed in a bucket, add one can of red grape juice concentrate,(homebrew shop again) Dissolve 2lb sugar in 2 pints of hot water & add to the bucket. Add more water to make it up to 1 gallon. add the acid reducing powder (if available) 1 teaspoon of yeast nutrient, & 1 teaspoon of pectolase. get a good quality yeast & add according to the insructions. Leave this to ferment for 3/4 days ,stirring twice daily. Then strain into a demijon, fit an airlock & ferment to dryness, approx 14 days.(During this time top up the demijon with water so that it is full) Leave it for another 14 days then siphon off the sediment that has formed in the bottom. Add 1 camden tablet & leave for 3 months. Siphon again & put a small portion of wine into a saucepan, warm this up & dissolve 8 to 10 ounces of sugar in it. Add this back into the wine ,leave to settle for a few days then bottle.
I bottle with t stoppers & leave the bottles up right, this helps in case of refermentation.
For the port style, use the same method but add extra fruit such as elderberries, plums ,damsons to take the weight of fruit up to 7lbs. This will take longer to mature, & possibly need more sugar at the sweetening stage.
Adrian.