Bring the quince juice with the preserving sugar and the scraped out vanilla pulp to the boil over high heat. Always stir well and let it simmer for about 3 1/2 to 4 minutes.
Make a gelling test: Put approx. 1 teaspoon full on a plate rinsed with cold water and let it flow back and forth. If the sample does not set, add a little lemon juice to the jelly and let it boil for a maximum of 1 minute.
Skim well and immediately fill the jelly full to the brim in clean jars placed on a damp cloth and close with twist-off lids. Turn the glasses upside down for the first 5 minutes to allow the air to escape.
The gelling process in the jar takes up to a week, allow the jelly to mature accordingly.
Tip: Incidentally, jars with a volume of up to 300 ml to 350 ml are best suited for jellies.