Wash, trim and weigh the rhubarb. Cut in pieces and place in a large bowl in layers with the sugar; grate in the lemon rind and add the juice. Cover and leave overnight.
Then place the contents of the bowl in a preserving pan or a large thick-based saucepan with the bruised ginger, tied in muslin.
Heat slowly to dissolve the sugar, then bring to the boil and boil rapidly, to setting point, about 15 minutes.
Remove the muslin bag.
Pot and cover in the usual way; label and date. (See 'Potting and covering' for details).