Preparing the Fruits

1. Bring a large pot of water to a full boil. Drop the peaches in the boiling water and boil for one minute. Immediately remove them from the water and cool them quickly in ice water. After cooling, slip off the peels from the blanched fruit.

2. Wash strawberries in cool, running water. Cut off the green tops.

3. Slice the strawberries into halves or quarters. Cut peaches into slices, removing and discarding the pit from each fruit.

4. Mash the fruit together in a large pot, using a potato masher. Sprinkle the fruit with 2 teaspoons of lemon juice for every 6 pounds of fruit and stir it in to prevent the peaches from browning. Lemon juice isn't necessary if you use a pectin that contains citric acid.

5. Heat the fruit on the stovetop. Stir in the sugar and pectin, following the recommended sugar and pectin amounts on the pectin package. Generally, use one pectin envelope and 4 cups of sugar for every 6 cups of fruit for low-sugar preserves. Use as many as 7 cups of sugar for regular preserves. If you prefer runnier preserves, such as for a dessert sauce, forgo the pectin and add sugar to taste.

6. Bring the fruit to a full boil. Boil for one minute so the pectin can begin to gel the fruit.

Canning Process

1. Wash the canning jars, rings and lids thoroughly in warm, soapy water. Submerge the jars in hot water immediately before filling them with preserves, or the cold glass may crack when you add the hot fruit.

2. Fill a waterbath canner half full with water. Cover the canner and bring the water to a boil as you fill the jars.

3. Set a canning funnel atop a jar and pour in the hot fruit mixture, filling the jar to within ½ inch of the rim. Repeat for each jar. Wipe the rims of the filled jars with a clean towel to remove any spills, then set a canning lid on top with the rubber gasket facing down. Screw on a canning ring to secure the lid.

4. Place the jars in the boiling water in the canner, using a jar lifter tool to avoid burns. Add more water, if necessary, so the tops of the jars are submerged to a 1-inch depth. Bring the water back to a full boil. Process half-pint jars for five minutes at altitudes lower than 1,000 feet, or 10 minutes at altitudes greater than 1,000 feet.

5. Lift the jars out of the canner at the end of processing, using the jar lifter. Set the jars on a towel in a draft-free area and allow them to cool for 24 hours. The raised center of each lid pops inward so you can't press on it if the jars seal correctly. Wipe the jars with a damp cloth to remove any fruit juice before storing them in a dark, cool pantry.