Until last Sunday, I had never been blackberry picking. It was inevitable, then, perhaps that I managed to get caught on brambles no fewer than four times during our excursion. But I emerged physically and figuratively victorious, with stained fingers, and overflowing tupperware. After two large boxes, crammed tight with blackberries were wedged into the freezer, for dark crumble-filled days, there was still a surplus of berries. So I made this vinegar.