Step 1
Inspect 7 half-pint jars for cracks and rings for rust discarding any defective ones. Immerse in simmering water until jam is ready. Wash new unused lids and rings in warm soapy water.
Step 2
Add raspberries to a blender or food processor; blend until smooth. Pour into a large saucepan.
Step 3
Cut off orange zest and finely chop. Add to the saucepan with the raspberries. Segment oranges and remove all the white pith seeds and fibrous membranes. Cut orange filets into small pieces; you should have 2 cups. Combine orange pieces with lemon juice in a bowl and mix. Add orange pieces and 1/4 cup sugar to the saucepan with the raspberries.
Step 4
Stir in pectin and slowly bring to a full rolling boil. Add remaining sugar and stir to dissolve. Return to a full rolling boil on high heat and boil for exactly 1 minute stirring constantly. Skim off any foam with a ladle or a large spoon.
Step 5
Remove from heat and ladle jam into the prepared jars filling to within 1/4 inch of the top. Run a clean knife or thin spatula around the insides of the jars to remove any air bubbles. Wipe rims with a moist paper towel to remove any spills. Top with lids and tightly screw on rings.
Step 6
Place a rack in the bottom of a large stockpot and fill halfway with water. Bring to a boil and lower jars 2 inches apart into the boiling water using a holder. Pour in more boiling water to cover jars by at least 1 inch. Bring to a rolling boil cover and process for 10 minutes.
Step 7
Remove the jars from the stockpot and place onto a cloth-covered or wood surface several inches apart. Let rest for 24 hours without moving the jars. Gently press the center of each lid with a finger to ensure the lid does not move up or down. Remove the rings for storage and store in a cool dark area.