Kaffir lime leaves add an exotic citrus note to the sweet and mellow nectarines. Use fresh or frozen leaves (available in some Indian markets) but not dried leaves, because most of the flavor will be lost. Note: This recipe produces a firm set.
You will need one small piece of cheesecloth and kitchen twine. For easy lifting, use a jar lifter or tongs with rubberized/silicone ends to transfer the jars into and out of the hot-water bath.
Make Ahead: The fruit mixture needs to macerate for a few hours at room temperature. The jarred jam needs to cool for at least 6 hours and preferably overnight before serving or storing. Store the jam in a cool, dark place for up to a year; once opened, it can be refrigerated for 2 to 4 months.
Servings: 4 half-pints
- 2 pounds white nectarines
- 4 kaffir lime leaves (see headnote)
- Freshly squeezed juice from 1/2 lemon (2 tablespoons)
- 2 tablespoons (1 ounce) peeled, finely chopped ginger root
- 2 cups (16 ounces) sugar
- 1 tablespoon calcium water (see NOTE)
- 2 teaspoons pectin (see NOTE)
Fill a stockpot with water and bring a boil over high heat. Fill a large bowl wtih ice water and ice cubes.
Add the nectarines to the pot; blanch them for about 1 minute, then transfer them to the ice-water bath for at least 30 seconds; this will help loosen the skins. You should be able to easily pull the skin off with your hands. Coarsely chop the nectarines and remove their pits. You should have about 5 cups; place in a nonreactive (glass or plastic) bowl or container.
Bruise the kaffir lime leaves by pounding them with the flat side of a paring knife for a few seconds each; tie them up in a piece of cheesecloth.
Add the lemon juice, ginger, 1 cup of the sugar and the kaffir lime leaves in the cheesecloth to the chopped nectarines. Stir well. Let them macerate at room temperature for a few hours, until the fruit releases its juices. Stir every once in a while to dissolve the sugar.
Transfer the macerated fruit to a 6-to-8-quart nonreactive pot and add the calcium water; stir well and let it sit just until you are ready to cook.
Wash and rinse 4 half-pint jars and put them in a stockpot; cover the jars with water (by an inch or so) and bring to a boil; turn off the heat. Let them stand in hot water until you are ready to fill them.
Place new lids and rings in a small saucepan and cover with several inches of water. Heat over medium heat but do not let the water come to a boil; turn off the heat. Let stand in hot water until you are ready to fill the jars.
Place a few metal spoons in the freezer for testing the consistency and gel of your jam later. Or place them in a cup of ice water, if you prefer.
Combine the remaining cup of sugar and the pectin powder in a bowl or measuring cup, using a fork to incorporate them evenly.
Place the pot of macerated fruit over medium-high heat and bring to a boil. Skim off and discard any foam that forms on the surface. Remove and discard the kaffir lime leaves in cheesecloth.
Gradually, carefully stir the pectin-sugar mixture into the boiling jam. Stir vigorously for 1 to 2 minutes to dissolve the pectin. Return the fruit to a boil, then remove it from the heat. Skim off any foam that has formed on the surface. Pectin gels completely when it's thoroughly cool, so don't worry if your jam looks loose while still hot.
To test, place a teaspoon of the hot jam onto one of the frozen spoons; let it cool to room temperature (about 30 seconds) on the spoon. If it thickens to the consistency desired, the jam is ready. If not, mix in a little more pectin (1/2 teaspoon into 1/4 cup sugar) and bring it to a boil again for 1 minute. Let the jam rest for 2 minutes.
Drain the jars, lids and rings. Fill the jars, leaving 1/4-inch of headspace at the top. Use a clean chopstick to gently stir the contents of each jar, releasing any air bubbles. (Air bubbles can cause seal failure or discoloration.) Wipe the rims of the jars so they are free of any food particles. Place the lids and gently tighten the rings.
Place a rack or towel at the bottom of the (same) stockpot; bring to a boil over high heat. Use a jar lifter or tongs to place the filled jars upright in the boiling-water bath, making sure there is at least 2 inches of water above the jars (add water as needed). Process for 6 minutes. Turn off the heat and let the jars rest in the water for 2 minutes, then transfer to the counter to cool completely for at least 6 hours or preferably overnight before serving or storing. The lids should be slightly depressed at the center; that is a sign of a successful seal.
NOTE: Calcium water activates powdered citrus pectin, which makes the jam set. Use Pomona's Universal Pectin (available online at <a href='http://pomonapectin.com/'>PomonaPectin.com</a> and at some natural foods stores), which comes with packets of citrus pectin and calcium phosphate. The latter is mixed with 1/2 cup water to produce the calcium water used in this recipe. You'll have plenty left over; it can be refrigerated.
Adapted from "Jam On: The Craft of Canning Fruit," by Laena McCarthy (Viking Studio, 2012).
Tested by Cecilia Stoute.
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