Prepare canner, jars, and lids. See The Ball Complete Book of Home Preserving for instruction and additional reference.

Place a saucer with 3 spoons on it in your freezer

Wash your fruit well.

Using a serrated-edge vegetable peeler, remove the zest from the fruit. (A regular vegetable peeler doesn't work quite as well, it seems to get more of the bitter white pith)

Chop the zest into fine strips.

Fill a pot with 2 quarts of water and add the zest.

Bring the water to a boil, reduce the heat to medium-high and simmer for 25-30 minutes, until the zest strips are tender

While the zest cooks, cut the fruit away from the remaining pith and membranes. This is most easily done by cutting off the top and bottom of the fruit and skimming down the sides with a sharp knife, just between the fruit and the pith.

Once the pith is gone, cut the fruit out from each membrane, saving the pits and the membrane in one bowl and collecting the fruit and juices in another bowl.

These seeds/membranes will provide the pectin to this marmalade.

Tie up the membranes and seeds into a piece of cheesecloth, secured tightly so no seeds escape.

Drain the zest in a fine mesh sieve, reserving the cooking liquid.

In a large pot, combine the drained zest, segmented fruit and juice, 4 cups of the reserved cooking liquid, 6 cups of sugar, and the bundle of seeds/membranes.

Bring to a vigorous boil and cook until the mixture reaches 220'F (between 30-40 minutes), stirring regularly.

When the marmalade reaches 220' and stays at that temperature for 1 minute even after being stirred, remove the pot from the heat.

Put a dollop on the frozen plate and return it to the freezer for 1-2 minutes. If at the end of the 1-2 minutes the marmalade 'wrinkles' when pushed, then you are ready to proceed with canning. If not, then return the pot to the heat and cook for an additional 5 minutes.

Once you believe the marmalade has set, remove it from the heat and pull out the cheesecloth bundle, forcing as much of the goodness out of it as you can by pushing it against the side of the pot.

Spoon your jam into hot jars, leaving 1/4 inch headspace.

Remove air bubbles and wipe the rim.

Center lid on the jar

Screw band down until resistance is met, then increase to fingertip tight.

Place jars in a canner, making sure they are completely covered with water

Cover the pot and bring to a boil

Boil for 10 minutes

Turn the heat off, remove the lid and let sit for 5 minutes

Carefully remove jars with a jar lifter and place them on a rack where they can be undisturbed for 24 hours.

Refrigerate any jars if their lids don't pop down.

Notes

This recipe assumes some knowledge of proper and safe canning techniques. Please see the Ball Complete Book of Home Preserving for guidance.