Water, kosher salt, brown sugar, 2 tablespoons pickling spices, pink curing salt, and garlic go into a large stockpot.
Bring brine to a boil and whisk to dissolve salt and sugar. Cool to room temperature after removing from heat. Cool in the fridge.
Oven-roasting bags should be nested like Russian dolls. Place one into the other after opening them. Place the brisket in the inside bag and gently pour the cooled brine.
Both bags should be sealed. Press out as much air as possible before sealing. To uniformly coat the meat, flip it several times before putting it in the fridge.
Make room in the fridge for the brisket. Put it in the fridge for 10 days to let the meat absorb the spices. To keep the brisket uniformly coated, flip it periodically.
Corned beef is nearly done after 10 days. Remove it from the brine to wake up the brisket. Rinse the brisket and cut it in half if necessary.
Then, add enough water to cover the brisket in a Dutch oven. Bring carrots, celery, and pickling spices to a boil.
Lower heat, cover, and add water as needed to keep brisket covered. Cook until meat is cooked, approximately 3 hours.
Finally, your corned beef may be served hot or cold. Thinly slice the brisket using a sharp knife. Serve it on a sandwich or with cooked veggies.