Step 1

Before you begin, prepare calcium water.To do this, combine ½ teaspoon calcium powder (in the small packet in your box of Pomona’s pectin) with ½ cup water in a small, clear jar with a lid. Shake well.Extra calcium water should be stored in the refrigerator for future use.

Step 2

Wash and rinse jars, lids, and screw bands. Set screw bands aside until ready to use. Place jars in boiling water bath canner with a rack, fill at least 2/3 of the way full with water, and bring to a boil. Boil jars for 10 minutes to sterilize (add 1 additional minute of sterilizing time for every 1000 feet above sea level), then turn down heat and let jars stand in hot water until ready to use. Place lids in water in a small pan, bring to a low simmer, and hold there until ready to use.

Step 3

Wash oranges thoroughly. Using a vegetable peeler, remove the orange part of the peel from 2 of the oranges. Slice these peels into thin, length-wise strips about 1 inch long, and set aside.

Step 4

Remove and discard the remaining white pith from the two peeled oranges, removing any seeds as well. Then, remove and discard the peel, pith, and seeds from the remaining 4 oranges.

Step 5

Pull all 6 peeled oranges apart into segments, then chop these segments into small pieces.

Step 6

Combine the chopped orange, the sliced peel, the 3 cups of water, and the cocoa powder in a large sauce pan. Cover the mixture and bring to a boil over high heat. Reduce heat and simmer, still covered, for 20 minutes, stirring occasionally. Remove the pan from the heat.

Step 7

Transfer the mixture into a bowl or other heat-proof container, then measure out 6 cups of the mixture. (If you have any left over, you can use it for something else.) Pour the measured quantity of the mixture back into the sauce pan. Add the lemon juice and the calcium water, and stir to combine.

Step 8

In a separate bowl, combine the sugar and the pectin powder. Mix well and set aside.

Step 9

Put the sauce pan on the stove and bring the orange-chocolate mixture up to a rolling boil over high heat. Add the sugar-pectin mixture, then stir vigorously for 1 to 2 minutes, still over the highest heat, to dissolve pectin. Return marmalade to a boil, then remove from heat.

Step 10

Remove hot jars from canner and fill jars with marmalade, leaving ¼ inch of headspace. Remove trapped air bubbles, wipe rims with a damp cloth, and put on lids and screw bands, tightening bands only to “fingertip tight” (until resistance is met, and then just the tiniest bit more).

Step 11

Place jars in the hot water, on the rack inside the canner. (Make sure jars are upright, not touching each other or the sides of the canner, and are covered with at least 1-2 inches of water). Place the lid on the canner, return the canner to a rolling boil, and boil for 10 minutes. (Add 1 minute additional processing time for every 1000 feet above sea level.)

Step 12

Turn off heat and allow canner and jars to sit for 5 minutes. Then remove jars from canner.

Step 13

Allow jars to cool undisturbed for 12 to 24 hours. Then confirm that jars have sealed. Remove screw bands from sealed jars, rinse off outside of jars if necessary, label jars, and store for later use.