The resulting turkey was indeed moist and delicious, though I'm still not convinced the brining was responsible. However, the process was easy enough, and the orange-spiced cider smelled heavenly, so I will try this recipe again. I couldn't find a brining bag but my 18# bird fit perfectly in two eight gallon trash can liners (I double bagged the turkey so the brine wouldn't leak out).
I set the entire bundle inside a large dishpan and refrigerated it overnight. I recommend placing the turkey breast side down overnight, and then flipping it in the morning until ready to stuff. This way, the breast will be well brined.
This recipe is supposed to cover a 12# turkey. If your turkey is larger, proportionately increase the liquid, salt and sugar.
8 cups spiced apple cider (I used Trader Joe's Spiced Cider) see note below
2/3 cup salt
2/3 cup sugar
note- if you can't find spiced cider, use regular apple cider, but add the following spices to the saucepan:
1 T whole allspice, crushed
1 1 inch piece of fresh ginger, peeled and sliced
6 whole cloves
2 bay leaves
2 oranges, quartered (set aside)
Combine everything but the oranges, in a large saucepan, and bring to a boil, stirring to dissolve the salt and sugar. Remove from heat, and let cool (I added a handful of ice cubes to hasten the process).
Clean the turkey, inside and out, removing the giblets. Stuff the orange quarters inside the cavity. Place the turkey inside the bag/s. Carefully add the brine. Tie or twist the bags so the brine does not leak. Place in a pan, and refrigerate up to 24 hours.