This jam does not set very firmly, but it has a delicious fresh flavour. Do not wash the raspberries unless absolutely necessary; if they have to be washed, drain very thoroughly.
Bring the fruit gently to the boil, then boil rapidly for 5 min. Remove from the heat, add the warmed sugar and stir well over a low heat until all the sugar has dissolved. Bring to the boil and boil rapidly for 1 min. Skim quickly, pour the jam at once into dry, warm jars and cover.