Water, kosher salt, brown sugar, 2 tablespoons pickling spices, pink curing salt, and garlic in a large stockpot. Simmer the brine until salt and sugar dissolve. Cool down.
Oven-roasting bags are now Russian nesting dolls. Put one into the other. Place the brisket in the innermost bag and gently pour the cooled brine.
It should cover the brisket. Seal both bags. Press as much air out before sealing. Turn the meat before putting it in the fridge.
Prepare a fridge spot for the brisket. For 10 days, refrigerate the meat to absorb the spices. For even coating, flip the brisket periodically.
Corned beef is nearly ready after 10 days. Remove the brined brisket to rouse it. Rinse and chop the brisket to suit your cooker.
Then, cover the brisket with water in a Dutch oven. Bring carrots, celery, and remaining pickling spices to a boil over high heat.
Lower heat, cover, and add water to keep brisket covered. Cook until tender, approximately 3 hours.
Finally, serve your corned beef hot or cold. Slice brisket thinly with a sharp knife. Serve on a sandwich or with cooked veggies.