Barley Soup

1 lb. stew beef, cut in 1/2" cubes
1 med. onion, chopped
2 stalks celery, chopped
2 carrots, diced
3/4 c. barley
1 bay leaf
1 tsp. salt
Pepper to taste
6 c. beef stock

Cook on low in crock pot for 6 to 8 hours stirring occasionally.