Make the corned beef: Place the water into a large (6- to 8-quart) stockpot along with both salts, sugar, cinnamon stick, mustard seeds, peppercorns, cloves, allspice, juniper berries, bay leaves and ginger. Cook over high heat until the salt and sugar have dissolved. Remove from the heat and add the ice. Stir until the ice has melted. If necessary, place the brine into the refrigerator until it reaches a temperature of 45ºF. Once it has cooled, place the brisket in a 2-gallon zip top bag and add the brine. Seal and lay flat inside a container, cover, and place in the refrigerator for 10 days. Check daily to make sure the beef is completely submerged and stir the brine.