Add water, applecider (or juice), koshersalt, darkbrownsugar, orangeslices, garlic, peppercorns, bayleaves, and freshherbs to a large stockpot. Bring to a boil. Stir occasionally until salt and sugar are dissolved, about 10 minutes. Remove and cool completely to room temperature.
1 gallon water, 1 gallon apple cider, 2 cups kosher salt, 1 cup dark brown sugar, 3 medium oranges, 1 head garlic, 3 tbsp black peppercorns, 4 bay leaves, 6 sprigs fresh rosemary, 3 sprigs fresh thyme
Place turkey, breast side down, into brining vessel (brine bag, bucket, or large pot with lid). Cover with cooled brine solution. Cover and refrigerate according to brine times in notes.
Remove the turkey from the brine solution and rinse well inside and out with cool running water. Pat dry with paper towels and either season and roast or place on a wire rack over a rimmed baking sheet and refrigerate overnight (uncovered) to dry it out further.
Cook turkey according to best cooking times for the size of your bird (see notes).