Finally writing up my mothers recipe for marmalade. Out of season for seville oranges, but someone asked me for the recipe over the weekend.
You do need a Large pan (I use a stock pot) and about 20 sterilized jam jars (prepare more just in case. How to sterilize Jam jars )
Wash and quarter, separating out pips and capturing any juice:
3.5 lbs of Seville Oranges
2 sweet oranges
1 lemon
Place pips in a muslin bag
Mince fruit and add to juice in the pan.
Add 11 pints water and leave for 24 hours
Boil for 1 hour with pips in their bag.
Add 13 lbs of sugar
Stir until sugar is dissolved and then bring back to boiling .... slowly
Boil until set is reached.
Pot and seal