Do-Ahead Turkey Stock

Make this up to 4 days ahead. Preheat oven to 450 °. Spread 5 pounds turkey wings (available at most supermarkets) and 1 turkey neck (from turkey cavity) on a rack set in a large heavy roasting pan. Brush with 1 tablespoon vegetable oil; roast until browned, about 1 hour. Chop 3 carrots, 2 celery stalks, and 2 onions; toss with 1 tablespoon vegetable oil. Arrange around turkey parts. Roast until vegetables brown, about 25 minutes. Transfer to a large pot. Add giblets (heart, gizzard, and liver) of 1 turkey and 1 gallon water. Bring to a boil, reduce heat to medium-low, and simmer, skimming surface occasionally, for 3 hours. Strain into another pot; boil until reduced to 2 quarts, about 30 minutes longer.