1 potato, cubed
2 tablespoons olive oil
1 (16 ounce) can wild mushrooms, drained
1 onion, quartered
2 stalks celery, quartered
2 tablespoons red wine
4 stalks celery, quartered
1 tablespoon Worcestershire sauce
4 1/2 cups water
1 teaspoon xanthan gum
1/2 teaspoon black pepper