Prepare your jars by washing them well and sterilising and drying in a 150°C for 10 minutes.
Pour half the blueberries into a large heavy based stainless steel pot. Mash roughly with a potato masher and add the water.Add the rest of the blueberries and cook until the juice begins to run.
Add the sugar and stir over a low heat until all the sugar dissolves. You can feel the sugar on the bottom of the pan like sand.Increase the heat and bring to a rolling boil. Boil for exactly 4 minutes. Use a kitchen timer.Skim the jam using a ladle.
Allow the jam to sit for 15 minutes to settle the fruit and distribute evenly.
Pour the hot jam into warm sterilised jars and cover immediately.
Allow to cool completely, then label and date the jam and store in a cool, dark place. Refrigerate after opening.
Recipe supplied by Rozanne Stevens