1. Saute onion, celery, and carrots in the bottom of stew pot. Remove from pan and set aside until later.
2. Mix flour, salt, and pepper together and coat the meat pieces. In bottom of stew pot, heat a small amount of olive oil. Brown meat in batches.
3. To the stewpot, add a little beer to deglaze the bottom of the pan. Add the meat, water, remainder of beer, and one or two large fat pieces (big pieces that are easy to locate and discard later). Heat to boiling, then reduce heat, cover, and simmer 1 1/2 hours.
4. Cut potatoes into quarters (about 1-inch cubes) and add to stew. Continue to simmer for 1/2 hour.
5. Remove fat pieces from the stew. Add the sauteed vegetables, bouillon cubes, bay leaves, mushrooms, 1-2 tablespoons salt, and the balsamic vinegar. Simmer 30 minutes, or until the potatoes are tender.