Lemon basil, if you can find it, adds an herbal note that plays well off the sweet tartness of the peaches. Regular basil, lemon thyme or lemongrass can be substituted.
Make Ahead: The fruit macerates for between 8 and 48 hours, either in the refrigerator or at room temperature.
Servings: 8 - 10 half-pints
- 6 1/2 pounds large ripe yellow freestone peaches
- 3 pounds sugar
- 1/2 cup freshly squeezed lemon juice
- 4 large branches (12 sprigs) lemon basil
Bring a large pot of water to a boil, reduce to a high simmer, and drop the peaches into the water for a minute or two. Drain and let them cool, then carefully slip the peels off with your hands or, if the peaches aren't quite ripe, with a paring knife. Halve and pit the peaches and cut them into 1/2-inch slices.
Put the slices into a mixing bowl and stir in the sugar and lemon juice. Cover with plastic wrap or parchment, pushing it directly onto the surface of the peaches, and macerate for at least 8 hours or as long as 48 hours, either in the refrigerator or at room temperature.
When you're ready to make the jam, put five metal teaspoons into the freezer for testing the jam later. Wash jars, rings, and lids by in hot soapy water and rinse them. Fill a water-bath canner or large stockpot equipped with a lid and a rack halfway with water and bring to a boil. Add the jars until covered by at least 1 inch of water (adding more water if needed), and boil for 10 minutes to sterilize. Turn off the heat and cover to keep the jars hot until you fill them. (You can also sterilize jars in the dishwasher; just keep hot until using.) In a separate small saucepan, cover the lids with water and bring just to a simmer, but do not boil.
Transfer the peaches to a large, wide pot set over high heat. Stir well to incorporate any undissolved sugar. Bring the mixture to a boil and let it boil for 5 minutes. Turn off the heat and skim off all the foam.
Return the mixture to medium-high heat and cook until thickened, stirring with a heat-proof spatula and scraping the bottom of the pot to prevent sticking or scorching, 25 to 40 minutes. (Lower the heat as the mixture thickens, also to prevent scorching.) Test for doneness by turning off the heat and placing a small amount of jam onto one of the teaspoons in your freezer. Return to the freezer for 1 to 2 minutes and check the consistency. If it’s too runny, continue cooking for a few more minutes and test again. While you're testing the consistency and the jam is off the heat, skim off any remaining foam. When the jam is as thick as you'd like, add the lemon basil sprigs or branches, pushing them under the surface of the jam.
Allow the lemon basil to steep for about 5 minutes, then taste the jam to make sure enough of the herbal flavor has come through, leaving it for longer if desired. Remove the lemon basil with tongs, shaking off excess jam, and discard.
Remove the jars from the hot water. Pour the hot jam into the sterilized jars, leaving 1/2 inch of head room. Run a chopstick around the inside edge of the jars to break up any air bubbles, wipe the rims clean with a moistened paper towel, and add the lids and screw on the rings until they are just barely tightened. Process by returning the jars to the canner or pot, making sure they are covered by 1 to 2 inches of water, and bring to a boil. Cover, and process for 10 minutes (from the time the water comes to a boil). Transfer the jars to a cooling rack to sit at least 24 hours undisturbed. They will seal as they cool; you may hear the satisfying pings as they do. Test seals after 24 hours by removing bands and lifting the jars by the lids to make sure the lids don't come off; transfer any jars that didn't seal to the refrigerator, where they can be stored for up to 3 months. The sealed jars can be stored at room temperature for up to 1 year.
NOTE: Times given are for altitudes up to 1,000 feet. Consult a site such as freshpreserving.com for high-altitude directions.
Adapted by Food editor Joe Yonan from recipes in "The Blue Chair Jam Cookbook" by Rachel Saunders (Andrews McMeel, 2010).
Tested by Joe Yonan.
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