Prep jars and lids. Wash the jars with hot, soapy water. Place the jars in the waterbath canner with enough water to fully submerge them. Set the burner to medium and let the jars simmer in hot water. Wash the lids and rings, then place them in a small pot filled with water. Place over low heat and let them simmer.
Prep oranges. Cut the top and bottom off the blood oranges. Remove the peels in small sections using a very sharp knife or a vegetable peeler.
Slice peels. Cut the peels into thin slices and set aside. You only need 2 cups of sliced peels.
Simmer peels. Add water, baking soda, and orange peels to a medium-sized saucepan or pot. Place the pot over medium heat and simmer covered for 20 minutes.
Chop. Remove the membrane (the white part) from the blood oranges. Roughly chop the blood oranges into pieces. You should have about 4 ½ cups of fruit and juice.
Simmer. Place the cut fruit and the lemon juice into a large 8-quart pot. Drain and place the peels into the pot. Cover and simmer the whole mixture on low for 10 minutes.
Add pectin. Add the pectin and stir until well combined. If you’re using butter, add it now. This will reduce foaming that happens during the boiling process, but it's not necessary.
Boil. Bring the mixture to a full rolling boil for 2 minutes over medium-high heat, stirring constantly throughout.
Add ginger and sugar. Stir in the ground ginger. Add the sugar all at once and stir to combine. Bring the mixture back up to a full rolling boil and boil for 1 minute. Remove from the heat, and skim any foam off the top using a slotted spoon.
Fill jars and add lids. Move the jars from the waterbath canner to a heat-safe area. Top with a canning funnel. Ladle the hot mixture into the hot jars. Fill the jars with a ¼ inch of headspace. Wipe the jar rims with a moistened paper towel. Place the jar lid on top, followed by a ring. Tighten the rings so they are fingertip-tight.
Process jars. Place the filled jars into the waterbath canner. Add a splash of white vinegar to the canner to prevent the jars from becoming cloudy (mineral build-up). Cover and bring to a boil. Once the water is boiling, process for 10 minutes, adjusting for altitude.
Cool and check seals. Turn off the heat, remove the lid from the waterbath canner, and let the jars sit in the canner for 5 minutes before removing them. Move the jars to a heat-safe space and cool for 12-24 hours. Check the lids for a proper seal by pressing on the center. The center shouldn’t pop up. Store in a cool place for up to 18 months.