I used this recipe to make my 4 Citrus Marmalade.
2-3 medium oranges
2 tangerines, peeled
4 cups water
1/4 tsp baking soda
5 1/2 cups sugar
Zest rind of lemons, limes, 2 oranges and grapefuit with a microplane. Place all in a stainless steel or enamel pan. Remove white rind (pith) and add to mixture. Add water; bring to a boil over high heat, cover, reduce heat and gently boil for 25 minutes.
Remove pith from limes. Finely chop all fruit pulp in a food processor. It will measure about 4 cups. If it doesn't measure 4 cups, add the extra orange pulp. Add fruit and baking soda to saucepan. Bring back to a boil over high heat, cover, reduce heat and gently boil for 20 minutes. Stir the mixture frequently. Using tongs, remove and toss the large pieces of rind.
Add sugar and return to boil, while stirring constantly. Boil rapidly, uncovered until mixture forms a gel, about 30 minutes. Stir this mixture frequently. Remove from heat.
Can in a BWB for 10 minutes.
Notes: I didn't have tangerines, so I added the other orange. I also didn't have 2 lemons, I had one. I substi
substituted more limes. I almost think that gave it a bitter overtone. I also am not sure why they used baking soda. It looked like a science experiment when I added it.