Best-Ever Turkey Brine

Combine 1/2 gallon water (8 cups) with all other ingredients in a large pot and place over medium heat. Bring to a boil, stirring frequently, then reduce to a simmer and cook until salt and sugar have dissolved completely. Remove from heat and add remaining 1 1/2 gallons (24 cups) water to pot. Stir to combine and let cool completely, around 1 hour. Submerge turkey completely in brine. If more water is needed, mix together additional brine by adding 2 tablespoons kosher salt to 1 cup of water, and stirring until dissolved. Brine overnight, or up to 24 hours.  When ready to roast, thoroughly rinse turkey and pat dry with paper towels.