You need 1 kg blackberries, 40° fruit alcohol, 450 g sugar, 10 cl water….and patience…
Quickly wash your berries under running tap water and then put them in a jar and fill up the jar with alcohol.
Leave it in the dark for 3 months- a year can do !!!
Then filter your preparation and squeeze the juice out of the berries (in a cloth for example). Make a sugar syrup with the other ingredients. Let it cool after boiling and add it to your juice. Put it in a bottle and leave it again for 3 months more.