In a large saucepan, bring the apples (with their skins and seeds), water, and lemon juice to a boil. Reduce the heat, cover and simmer gently for 15 minutes. Do not crush the apples while cooking. Add the raspberries and bring to boil. Cover and continue cooking for 10 minutes.
Line a colander with several layers of cheesecloth and place it over a large bowl.
Pour the fruit in the colander and let drain for about 1 hour without crushing or squeezing the fruit. You should get about 1 litre (4 cups) of juice. If the amount of juice obtained is different, remember that it takes about 180 ml (3/4 cup) of sugar per 250 ml (1 cup) of juice.
In the same pan (cleaned), bring the juice and sugar to a boil. Attach a candy thermometer in the centre of the pan. Simmer for about 30 minutes or until the thermometer reads 106 °C (222 °F). Skim the surface during cooking.
Pour into sterilized jars. Freeze or sterilize according to the sterilization technique (see article Sterilization 101).
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.