1. Place the quartered beets in a large saucepan. Thinly slice 4 ribs of the celery and add to the beets. Pour in enough cold water to cover the vegetables by 1 inch. Bring to a gentle bubble and cook, uncovered, for 20 minutes or until the beets are tender.
2. Transfer to the container of a blender or processor and whirl until smooth. Return to the saucepan and add the beef broth, salt, and pepper. Cut the remaining 2 ribs of celery into 2-inch lengths. Slice the lengths into julienne strips and add to the consommé. Cover and cook over low heat and stir in the lemon juice. Ladle into clear glass bowls and serve hot.