In large food storage bag, shake beef with 1/4 cup flour, 1 1/2 teaspoons salt and the pepper. Melt butter in large Dutch oven over medium heat. Brown beef; remove. Stir in onion, carrots, thyme, bay leaves and garlic; sauté 4 minutes. Stir in beef stock and beer. Reduce heat; simmer, covered, until beef is tender (approximately 3 1/2 hours). Add potatoes; simmer until tender (about 20 minutes). Combine remaining 1/4 cup flour and water until smooth; slowly pour into stew, stirring constantly. Cook over medium heat until mixture comes to a boil; boil and stir 1 minute, stirring constantly. Remove bay leaves. Stir in remaining 1 teaspoon of salt if needed.