In a large, heavy bottomed pot like a dutch oven, fry the bacon over medium-high heat for about 5 to 6 minutes.
Add the onion and garlic and cook until the onions are wilted, about 4 minutes. Add the beer, chicken stock, vinegar, and sugar and bring to a boil.
Begin adding the greens in batches, pressing down with a spoon to submerge them in the hot liquid and adding more as they wilt.
When all of the greens have been added, reduce the heat to a simmer. Cook the greens, partially covered, and stirring occasionally, for about 1 to 1 ½ hours or until tender. You can also transfer the greens to a crockpot over low heat for 3 to 4 hours, until tender.
