Sort the raspberries, wash and dry if necessary. Weigh out 1 kg pulp
Mix gelling agent and sugar (for diabetics, fructose or sorbitol) in a large pot. Add fruit and juice. Mix everything well. (If using sweetener, first mix fruit and sweetener in the pot, then stir in the gelling agent).
Bring everything to the boil while stirring over high heat. Boil for at least 3 minutes while stirring. Immediately fill jam to the brim into prepared twist-off jars. Seal, let cool upside down