In a blender or food processor, crush the currants.
Pour into a large saucepan.
Add the water and bring to the boil.
Reduce heat, cover, and simmer for 15 minutes; cool slightly.
Pour mixture into jelly cloth or bag.
Squeeze out juice into a large saucepan.
Add the food coloring, sugar replacement, and jelling mix; stir to completely dissolve.
Place over high heat and bring to the boil.
Boil hard for 2 minutes, stirring constantly.
Remove from heat and skim any foam from surface.
Pour into jelly glasses, leaving 1/2 in. (1.25 cm) space at top for sealing.
Seal with hot paraffin or sealing lid.