This recipe is taken from Marks & Spencer’s Home Preserves cookery book (a variation of Orange & Thyme Jelly)
16 oranges (2kgs)
10 lemons (1kg)
7 limes (600g)
aprox. 2.8kgs sugar
Couple small plates or dishes in the freezer
Measure the juice (I got 3L 450ml), pour into a large pan and bring to the boil. Now add 500g sugar for every 600ml juice (3,450 divided by 600 = 5.75, therefore 500g sugar x 5.75 = 2.875g sugar). Heat gently, stirring until the sugar is disolved. Bring to the boil, then boil rapidly until setting point is reached (15-20mins), removing any scum immediately. I check the setting point by dripping a small amount of liquid onto the small plate or dish taken directly from the freezer – in a few seconds it should be kind of sticky when touched.