Place the corned beef briskets into a large pot. Sprinkle in 1/2 of the spice packet, and discard the rest. Pour in the beer, and fill the pot with enough water to cover the brisket by 1 inch. Add the bay leaf, peppercorns and garlic cloves. Cover, and bring to a boil.

Once the liquid comes to a boil, reduce the heat to medium-low, and simmer for 4 to 5 hours, checking hourly, and adding more water if necessary to keep the meat covered.

Carefully remove the meat from the pot, as it will be extremely tender. Set on a cutting board, and allow it to rest until it firms up a bit, about 10 minutes. Slice or shred to serve. I discard the cooking liquid, but it can be used to cook cabbage and other vegetables if desired.