Wash the grapes and pat dry. Cut in half and remove seeds. Weigh 150 g of flesh. Score the vanilla pod lengthwise, scrape out the pulp with a knife
Boil up wine, grapes, jam sugar, vanilla pulp, vanilla pod and citric acid in a large pot while stirring over high heat. Boil for at least 4 minutes while stirring continuously
Remove the vanilla pod. Immediately fill jelly to the brim into prepared twist-off jars. Seal and let cool upside down