If you’ve never canned anything before, this is a relatively easy project to start with and I’ve included the instructions for doing it.  Having said that, the jam itself is a little trickier to make than some.  It’s also a slow process because it’s a pectin-free recipe, and the marmalade cooks for a very long time.  But once it begins to thicken, it will do so fairly quickly and needs to get canned before it begins to stick to the pot.  Like any other canning project, it will take up most of your stove space during the last phase so don’t do it on a day when you are planning doing a lot of other stovetop cooking.  Also note that from start to finish, this jam takes almost two days, but most of that is just soaking time.

Scrub the peels of 6 Mandarins and 4-6 lemons.  Cut them in half and remove all the seeds (if any).  Use a juicer to squeeze out the juice into a measuring container.  Pour the juice into a large non-reactive pot, and then add an equal amount of water.

Using a very sharp knife, thinly slice the squeezed fruits — including rind and pith.  Dice at least half of the slices, depending on how chunky you want it to be.  Measure the chopped fruit in a measuring container and add to the pot with the juice.  Add an equal amount of water to the amount of fruit measured.  Important: Make a note of the total quantity of fruit, juice and water in the pot in total cups.

Let the fruit soak in the water for 12 hours, then bring to a boil and simmer for 30 minutes.  Let stand again for another 12 hours.

Add 1/2 C. of sugar for each cup of fruit/juice/water in the pot.  Bring to a boil and simmer for several hours, until the mixture cooks down by a third to a half.  Taste the liquid and add more sugar if you want it to be sweeter.

Transfer the marmalade in batches into a pot that is small enough to pour into canning jars, 6-8 Cups, preferably with a single handle.  If possible, keep the big pot simmering.

Bring water to boil in another pot that is big enough to fit 2-3 half-pint canning jars.  This is to sterilize the jars and lids.  Use a tongs to drop the jars and lids into the water.  Try to keep the lids and their rings together, as it will make removal easier.

Use a spoon to test the marmalade as it thickens.  You want it to be the consistency of maple syrup, but not as thick as honey.  The jam will thicken further when it cools.

When it is ready, remove the canning jars one at a time from the water with the tongs, emptying the water out of the jar and adding new ones into the water as you go.  Pour the hot marmalade into the jars, leaving as little space as possible on top.  Take care to avoid getting any jam on the rim of the jar, and wipe it clean with a paper towel if you do.  Use the tongs to remove the lid and ring from the water, then drop it onto the jar.  Use the ring to center the lid and tighten it down — but not too tight.  Remember both the jars and lids will be hot!

Repeat the process until the small pot is empty, then fill it again and keep going until you finish all the marmalade.

Bonus item:  the sticky residue inside the large pot  will make a few tasty pieces of fruit leather that will peel off once it is dry and congealed.  It’s also easier than trying to wash it off.

The jars of marmalade should seal in a few hours or overnight as the liquid inside cools.  Check the “buttons” on each lid the next day.  If you can easily make a dent in the top, the jar did not seal.  An unsealed jar can be kept in the fridge for several weeks and used, but it will go bad if kept at room temperature.