Pour the cold tomato juice into a small bowl, sprinkle the gelatin evenly over it and let it bloom for 5 minutes.
Heat the remaining tomato juice in a saucepan until steaming but not boiling.
Whisk in the bloomed gelatin until completely dissolved, then add the celery, lemon juice, Worcestershire, horseradish, salt and hot sauce.
Pour the mixture into a lightly oiled 4-cup ring mold and skim away any foam.
Refrigerate for at least 6 hours, dip the mold briefly in warm water and invert it onto a plain plate.