Dice the bacon, add to an already hot stockpot and allow it to crisp and the fat to render, about 5-8 min. Rinse the collard greens and remove the tough center stem of each leaf. Stack a few leaves together and slice them into thin strips. Repeat with the remaining leaves.
Add the diced onion and garlic to the bacon fat and saute until the onion is translucent. Add the beer to deglaze the pan, being sure to scrape up any brown bits that have formed on the bottom.
Add the sliced greens and stir until they are all moistened. Cover and cook for 5 minutes or until they begin to wilt. Add the spices and stock, reduce to low and cover. Allow to simmer, stirring occasionally, for 20 minutes. Uncover and cook for 15- 25 more minutes. (I like my greens to still have a bit of texture to them so I cook them for 35 minutes, if you like yours mushy go for the 45.)