Directions

1. 1

   Prepare a large, heavy saucepan and gather five half-pint mason jars (or equivalent glass jars). Wash the jars thoroughly, then sterilize them by either running them through a dishwasher's hot cycle or boiling them for 10 minutes. Keep sterilized jars in hot water (not boiling) until ready to fill. Similarly, warm the jar lids and rings in hot (not boiling) water to sterilize and soften the sealing compound.

2. 2

   Place the peeled and pitted peaches in a food processor and pulse until coarsely chopped into bite-sized pieces. Transfer to a large bowl.

3. 3

   Add the fresh blueberries to the food processor and pulse briefly until coarsely chopped, being careful not to reduce them to a liquid or puree—you want distinct chunks of fruit visible in the final jam. Combine with the chopped peaches; you should have approximately 4 cups of mixed chopped fruit.

4. 4

   Pour the chopped fruit mixture into your prepared saucepan, then add the lemon juice and calcium water. Stir to combine and place over medium-high heat. Bring to a boil, stirring occasionally to ensure even heating.

5. 5

   While the fruit is heating, whisk together the pectin and granulated sugar in a small bowl until completely incorporated with no lumps, ensuring the pectin is evenly distributed.

6. 6

   Once the fruit reaches a boil, add the pectin-sugar mixture and whisk vigorously for 1-2 minutes until it is completely dissolved. Continue stirring and let the mixture return to a full rolling boil (a boil that does not stop when stirred), then remove from heat immediately.

7. 7

   Allow the jam to sit undisturbed for 5 minutes, then skim off any foam that has risen to the surface using a clean spoon.

8. 8

   Using a ladle or jar funnel, carefully pour the hot jam into the sterilized jars, leaving 1/4 inch of headspace at the top of each jar. Wipe the jar rims and threads clean with a damp cloth to remove any residue.

9. 9

   Place the lids on the jars and screw the rings on until they are finger-tight (snug but not overly tight).

10. 10

    Process the filled jars in a boiling water bath for 10 minutes, ensuring the jars are covered by at least 1-2 inches of water. After processing, carefully remove the jars from the water bath and place on a clean towel or rack to cool.

11. 11

    Allow the jars to cool completely at room temperature for 12 to 24 hours. Check the seals by pressing on the center of each lid—properly sealed lids should be firm and not flex. Any jars that failed to seal should be refrigerated and used within 3 weeks; properly sealed jars can be stored in a cool, dark pantry for up to one year.