Place bacon in Dutch over over medium heat. Cook for 5 minutes, or until lightly browned, stirring.
Add onion, celery and butter. Sauté 5 minutes.
Add flour and stir 4 minutes on medium.
Whisk in stock. Bring to a boil and boil 1 minute.
Reduce heat to simmer. Cook 15 minutes, stirring.
Add milk and simmer 15 minutes more. Do not boil after adding milk.
Remove from heat and stir in cheese, Tabasco, Worcestershire sauce, salt and pepper, to taste, until soup is smooth.
Stir in beer. If soup is too thick, thin with warm milk.
Serve garnished with scallions or chives.