In a Dutch oven or large pot, cover rib bones, onion, celery and carrot with about 8-10 cups water. Bring to a boil, then allow to simmer over low heat for about 3 hours. Strain broth, then store in air tight containers in the refrigerator or freezer. Reserve the meat for soup.
Make the Beef, Mushroom and Barley Soup:
In a small bowl, cover barley with boiling water and allow to sit for about 10-15 minutes. Drain and rinse well, set aside.
In a Dutch oven or soup pot, heat olive oil over medium heat. Sauté onions until transparent. Add garlic, celery, carrots, and mushrooms and continue to stir and sauté until mushrooms begin to wilt, for about 5 minutes. Add softened barley, beef stock, meat from beef ribs, and season with salt and pepper.
Bring to a boil then lower heat and allow to simmer, partially uncovered, for about 30 minutes, or until barley is fully cooked and tender. Stir in sherry vinegar, soy sauce and thyme. Adjust seasoning with salt and pepper. Enjoy!
Notes
Barley of any variety will work in this soup, however, I prefer the dainty pearl barley for its chewy texture and faster cooking time.