Put the water, mushrooms, onions, carrot, and garlic in a large soup pot and bring to a boil over medium-high heat. Decrease the heat to medium-low, cover, and cook for 10 minutes.
Put 1½ cups (375 ml) of the beans and 1½ cups (375 ml) of the bean liquid in a blender and process until smooth. Pour into the soup pot. Add the remaining 1½ cups (375 ml) of the beans, the remaining 1½ cups