Brown small cubes of stew meat in vegetable oil over medium heat until juices become a rich brown color. Add 2 cups water, and simmer meat while preparing the vegetables.
In a large soup pot, melt butter or margarine over medium heat. Saute carrots, onion, garlic, celery, and mushrooms.
Add meat, 6 cups water, bouillon cubes, and barley to vegetable mixture. Cook until barley is soft, about 1 hour. Adjust liquid and seasoning as desired. Remove from heat, and stir in sour cream. Serve immediately.