In a large pot bring add the water and the remaining brine ingredients. Bring to a simmer and stir to dissolve the salt and sugar. Remove from the heat, allow to cool to room temperature and refrigerate until thoroughly chilled.
Add the venison roast to the brine. Place a plate on top of the meat to keep completely submerged. Cover and refrigerate for 3 days.
Remove the venison from the brine, rinse it and then dry it thoroughly. Discard the brine.
In a small container mix the juniper, black pepper and coriander until evenly combined. Coat the venison completely with these spices.