This marmalade recipe perfectly preserves the bright color and flavor of kumquats. Kumquat fruits are only in season for a few weeks in late fall and early winter, but this marmalade makes it possible to enjoy their unique taste year-round. The addition of an orange to the kumquat fruits adds depth to the citrus flavor.
There is no need to add commercial pectin to this recipe. The natural pectin present in the citrus peels combined with the sugar and the acidity of lemon juice ensures a good gel.
- 34 kumquats, approximately 1 1/2 inches long and half as wide (you can use a mix of slightly smaller and larger kumquats, but none should be longer than 2 inches)
- 1 orange
- 6-7 cups water
- 4-5 cups granulated sugar
- Juice of 2 lemons
- Wash the whole kumquats and the orange well.
- Slice the whole kumquats into fine slivers, removing and discarding any seeds as you go. Do the same with the orange.
- Measure the sliced kumquats together with the orange and any juice that came out while you were slicing the fruit. Transfer the measured fruit and juice into a large, non-reactive pot. Stir in 2 cups water for every cup of fruit and juice. Cover and let sit at room temperature for 4 hours (overnight is okay, too).
- Sterilize your canning jars. Meanwhile, bring the fruit and water mixture to a boil over high heat. Reduce the heat and simmer until the peels are translucent and very tender, about 1 hour.
- Measure the cooked fruit mixture. Add 3/4 cup granulated sugar for each cup of the cooked fruit. Add the lemon juice. Bring all of the ingredients to a boil over high heat. Stir constantly until the sugar is completely dissolved.
- Continue to boil over high heat, stirring frequently, until the marmalade reaches the jell point. Turn off the heat. Skim off any foam on the surface.
- Ladle the hot marmalade into the sterilized canning jars. Leave at least 1/2-inch of head space between the surface of the marmalade and the rims of the jars. Screw on canning lids. Process in a boiling water bath for 5 minutes.
Once the jars have sealed, store kumquat marmalade away from direct light or heat. It will keep for at least a year. Opened jars must be stored in the refrigerator, where they will keep for several months.
Note: marmalades are unusual among sweet preserves in that they will continue to "set up" for days, even weeks after they cool in the jars. If your just-cooled marmalade seems slightly runnier than you'd like, try waiting for 2 weeks to see if it reaches a firm jell.