Bring the water with the scraped out vanilla pulp and the vanilla pod to the boil and let it steep for 10 minutes. Then bring to the boil again and dissolve the coffee powder in it. Now add the orange juice, the orange zest and the citric acid. Stir in the preserving sugar and let it simmer for 3 or 4 minutes according to the instructions. Take off the stove and add the rum. Remove the vanilla pod. Pour hot into glasses.