Select the raspberries, wash them carefully if necessary and let them drain. Drain the pineapple and collect the juice. Cut the pineapple into very small pieces
Mix fruit, pineapple juice, jam sugar and citric acid well in a large pot. Bring to the boil while stirring constantly and let it boil effervescently for exactly 3 minutes from the beginning of foaming
Fill jam brimful into prepared twist-off jars and seal. Let cool upside down