Step 1
Inspect 8 half-pint jars for cracks and rings for rust; discard any defective ones. Immerse in simmering water until jam is ready. Wash new unused lids and rings in warm soapy water.
Step 2
Toast the almonds in an ungreased skillet until lightly colored 3 to 5 minutes. Set aside.
Step 3
Place crushed blueberries and blackberries in a large pot and add pectin. Slowly bring to a full rolling boil. Add sugar and lemon juice and stir to dissolve. Return to a full rolling boil for exactly 1 minute stirring constantly. Skim off any foam with a ladle or a large spoon.
Step 4
Remove the pot from the heat. Stir in gin and toasted almonds.
Step 5
Ladle jam immediately 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.