Wash and clean the strawberries and pat them dry well. Weigh 700 g of flesh. Select the raspberries, wash and dry if necessary. Weigh out 500 g fruit flesh
Mix fruit, sparkling wine, citric acid and jam sugar in a large pot. Bring to the boil while stirring over high heat. Boil for at least 3 minutes while stirring continuously
If necessary, skim jam with a skimmer before filling. Immediately pour into prepared twist-off jars and close them tightly. Turn over, place on the lid and allow to cool