In a Dutch oven, melt butter over medium-high heat. Add celery, carrots and onion; saute until crisp-tender. Add broccoli and red pepper; stir in broth and pepper. Combine flour and water until smooth; gradually stir into pan. Bring to a boil. Reduce heat; simmer, uncovered, until soup is thickened and vegetables are tender, 25-30 minutes., Stir in cheeses and beer until cheeses are melted (do not boil). Top with additional shredded cheese, bacon, green onions, sour cream and croutons or pretzel bites as desired.