Fragrant Blueberry Jam

1. 1
   Wash the jars, lids, and bands in hot, soapy water. Rinse well. Dry the lids and bands and set them aside.
2. 2
   Place the jars in a boiling water canner or a 15- to 20-quart pot fitted with a canning rack and a lid. Fill the pot with water and bring it to a boil over medium-high heat. Boil for 10 minutes, then turn off the heat.
3. 3
   Keep the jars in the hot water until you’re ready to use them.

For the jam:

1. 1
   Place a plate in the freezer to chill for testing the jam. Place the blueberries in a large, heavy-bottomed saucepan and crush them with the back of a wooden spoon until some of the berries are broken up and they start to release their juice.
2. 2
   Add the sugar and apple peel and stir to combine. Bring to a boil over medium-high heat. Boil vigorously, stirring frequently, until the jam reaches its setting point, about 15 minutes. (Bubbles will rise to the surface of the pan; if they get too high, just stir the jam until they decrease.)
3. 3
   Once the jam reaches 228°F, start checking if it’s properly set. Conduct the plate test: Put a spoonful of jam on the chilled plate and place it in the freezer until the jam reaches room temperature, about 1 minute. Draw your finger through the jam. If it immediately runs back together, it’s not ready. Once the jam is ready, remove it from the heat and stir in the lemon juice.
4. 4
   Remove the jars from the hot water with a jar lifter, letting any excess water drip off. Bring the water in the canner back to a simmer (about 180°F) for processing the packed jars. Fill the sterilized jars with jam, leaving a 1/4-inch headspace. (If you have a half-full jar, place it in the refrigerator and eat the jam within 5 days.)
5. 5
   To remove any air bubbles, slide a clean rubber spatula down the side of each jar and press inward on the jam while rotating the jar; repeat 2 to 3 times for each jar.

For processing the packed jars:

1. 1
   Wipe the rim and threads of each jar with a clean, damp towel. Place the lids on the jars, checking that the sealing compound is centered. Fit the jars with bands and tighten just until resistance is met.
2. 2
   Check that the water in the pot or boiling water canner is at a simmer (about 180°F), then set the jars in the canning rack. (The jars must be covered by 1 to 2 inches of water. Add additional boiling water as necessary.)
3. 3
   Cover the pot with a tightfitting lid and bring it to a rolling boil over medium-high heat. Process the jars for 10 minutes at a gentle but steady rolling boil. (Begin calculating the processing time once the water is at a rolling boil. Check occasionally that the water remains at a steady boil.)
4. 4
   Once processed, remove the jars with the jar lifter and set them upright, 1 to 2 inches apart, on a dry towel. Do not retighten the bands; let the jars cool at least 12 hours.
5. 5
   After the jars have cooled, check for a seal by pressing the center of each lid. If the center is concave and does not flex, remove the band and try to lift off the lid with your fingertips (don’t pull too hard). If you can’t lift the lid, there is a good vacuum seal. If the lid pops off, your jar did not properly seal. Eat the jam within 2 months.
6. 6
   To store properly processed jars, wipe each lid and jar with a clean, damp cloth (the bands don’t need to stay on for storage), label the jars, and store them in a cool, dry, dark place. Unopened jars can be kept up to a year when stored properly. Once opened, keep in the refrigerator and use within 2 months.