Smash blackberries and sugar together in a primary fermentation container.
Bring 1 quart of water to a boil and pour over the blackberries and sugar. Stir to dissolve the sugar.
Allow the mixture to cool to around 70 degrees and add the remaining ingredients, adding enough water to fill your 1-gallon fermenter.
Seal the fermenter with a blow off tube (this ferments a bit violently for a water lock) or leave open for the first part of the primary ferment, just covered with a towel. Stir the mixture daily for 5-7 days until the most vigorous fermentation is complete.
After about a week, wrack the blackberry wine into a glass carboy (narrow neck) and seal with a water lock. Allow the mixture to ferment for about 3 months before racking again.
At this point, allow the mixture to ferment for 8-12 months before bottling.
Allow the blackberry wine to bottle age at least 6 months before tasting.