Canan, the whale warrior from our pdc, kindly posted me this recipe, I hope you can do some marmalade while still a vale da lama (I know I am late)
Here comes the recipe for the marmalade, it was passed to me from my next door neighbor years ago, she is a lovely lady, now in her 80's :-)
6 cups of water
3 lbs of sugar
small piece of muslin cloth + string
a two day process:
day 1: first finely slice all the fruit, almost like shaving in think slices. save all the seeds and put them in a cup of water (now you have 5 cups left). put all the sliced fruit in a large pan with the rest of the 5 cups of water and leave over night.
day 2: bring the fruit and the liquid to boil, and simmer, bubbling but not violently, until the water in the pan is halved.
now add the sugar, and the water where you had kept the seeds. Also put the seeds in the cloth and dangle into the pan. This helps with the jelling, as the seeds are supposed to contain pectin.
cook for another 40 minutes or so or until it passes a jelling test (i.e drop a drop on a cold plate and see if it stays in a ball rather than enlarging in circumference).
put them in pre-sterilized jars, close caps and turn upside down for about 10 minutes. later you may of course trun them right side up :-))
now marmalade is ready. try to save some for immediate use and let the jars rest a few weeks before eating, the taste somehow matures, or so I'm told :-) this amount of fruit made over 1 1/2 lt of marmalade for me, if you want an idea for how many jars you may need.
this time I did not have grapefruit so i substituted 2 oranges and lime in its place, the result is delicisious.
enjoy your jam session & bon appetito :-)