Wash the apples, cut in quarters and place in a preserving-pan with the water and the bunch of mint. Simmer until the apples are soft and pulpy, then add the vinegar and boil for 5 min. Strain overnight through a cloth, measure the juice, and to each pint allow 1 lb. sugar. Put the juice and sugar into the pan and bring to the boil, stirring until the sugar is dissolved. Boil rapidly until setting point is nearly reached, add the chopped mint and colouring, then boil until setting point is reached. Pour into hot jars and cover immediately with waxed discs. When quite cold, tie down with parchment or transparent covers, label and store.