Preheat the sous vide water bath by adding water to a large container or pot, and set the Sous Vide Precision Cooker to 155°F (68°C). This is my recommended temperature, and if you’d like to cook them to different doneness, follow the guide in the recipe notes*.
Trim the excess fat from the brisket (optional).
In a small bowl, mix together garlic powder, paprika, salt, pepper, and cumin powder.
In another medium-sized bowl, whisk together BBQ sauce, minced garlic, brown sugar, olive oil, Worcestershire sauce, and salt.
Drizzle brisket with oil and rub the seasoning all over.
Place the seasoned beef brisket into a large vacuum bag or zip-lock bag. Then pour half of the BBQ sauce over the brisket.
If you use a zip-lock bag, seal it using the “water displacement” technique: Seal all but one corner of the bag, and slowly place it in the cold water. Make sure everything below the zip-line is covered by water. Then seal the rest of the bag. (If your brisket is too big for one bag, you can cut them into two pieces and use two bags.)
When the water has reached the set temperature, lower the bags into the water bath. Make sure the meat is fully submerged in the water with the bag seams above the water.
Cover with several pieces of aluminum foil and sous vide cook for 24 hours. This will minimize water evaporation.
After the brisket is sous vide cooked, let it cool down and remove it from the bag (don’t throw away the juices).
Mix 1/4 cup of the juices with the reserved BBQ sauce.
Pat dry with paper towels, and brush the brisket with the sauces.
Broil on high heat for 5-10 minutes, or until the edges of the brisket have charred and become crispy. (If you prefer to smoke your brisket, see the recipe notes below.**)
Slice brisket thinly across the grain and serve with remaining barbecue sauce.