In a large pot add all of the ingredients, except the beet root powder (if using), and bring to a boil. After all of the salt and sugar has dissolved shut off the heat.
Let the mixture cool completely. You can let this happen naturally, or you can place the brine in an ice bath by placing the brine inside of a clean bowl and then placing that bowl inside of another bowl filled with ice water.
Once the brine is cool place the beet root powder (if using) and brisket inside a 2 gallon plastic bag and place the bag inside of a large container that will catch any accidental drips. This container has to be able to fit inside of your refrigerator.
Carefully pour all of the brine inside of the plastic bag and seal it. Lay the plastic bag flat inside of the container and place in your refrigerator for 5-6 days.
Each day carefully turn the bag upside down to stir the brine and make sure all of the beef is submerged.
Once ready to cook discard the brine and the spices and rinse the corned beef thoroughly.
Traditionally corned beef is cured using a salt that turns the brisket pink. We are purposefully skipping this salt, also known as sodium nitrate because it's been labeled a possible carcinogen and is not necessary in this recipe. Without the sodium nitrate the corned beef is rather gray. We experimented with adding beet root powder to help counteract that and found that the resulting corned beef wasn't super pink, but it did change the color a bit. This is totally optional, and might not be worth buying a package of beet root powder just for this purpose if you are never going to use it again.