Place turkey in the bottom of a large stock pot or bucket. As long as you are able to cover the turkey with liquid, you should be ok.
In a pot, combine 1 quart of water, 1 cup of salt, sugar and apple cider vinegar. Bring this mixture to boil and once all of the salt has dissolved, take off heat. Add remaining 3 quarts of water, let cool.
Crush garlic and herbs with the back of your knife before adding them to your brine.
Once the brine is cooled, pour over turkey. Be sure the breast and legs are covered.
If the turkey floats, put a clean, heavy plate on top to submerge it.
Cover pot with lid and/or plastic wrap and REFRIGERATE for 12 to 24 hours.
Remove your turkey from the brine, rinse and set on a cooking grate to dry.
Carefully peel back the skin from the bottom of the turkey breast. You should be able to get your whole hand underneath without tearing the skin!
Cut the butter into small cubes, bruise the sage and carefully lay under the skin and on top of the breast.
Chop 2 cups of celery, onion and carrots and place on the pan under the turkey (these veggies will add more aroma and flavour to the turkey and your gravy).
Roast at 375℉ until the skin has become golden and beautiful, and cook until a digital thermometer inserted into the thickest part of the breast reads 160℉.
Let cool and carve! Prepare for a juicy, flavorful and delicious turkey!