Place 1.0 kg of peeled and chopped tomatoes in a saucepan with a lid.
Simmer over medium heat, stirring frequently for 10 minutes.
Stir in 1 1/2 teaspoons lemon zest, 1/2 teaspoon ground allspice, 1/2 teaspoon ground cinnamon, 1/4 teaspoon ground cloves, 1/4 cup lemon juice, and 1 package powdered pectin.
Place the saucepan over high heat and bring the tomato mixture to a boil, stirring constantly.
Immediately upon boiling, stir in 4 1/2 cups of sugar and return to a full rolling boil.
Cook at a full boil for 1 minute while stirring, then remove from heat and skim off any foam.
Sterilize the jars and lids in boiling water for at least 5 minutes.
Pack the tomato jam into the hot sterilized jars, filling them to within 1/2 inch of the top.
Run a knife or thin spatula around the insides of the jars to remove air bubbles.
Wipe the jar rims with a moist paper towel to remove food residue, then top with lids and screw on rings.
Place a rack in the bottom of a large stockpot and fill halfway with water.
Bring water to a boil, then carefully lower the jars into the pot using a holder, leaving a 2-inch space between them.
Add more boiling water if needed until the water level is at least 1 inch above the jar tops.
Bring the water to a full boil, cover the pot, and process for 5 minutes.
Remove the jars from the stockpot and place them several inches apart on a cloth-covered or wood surface.
Allow the jars to cool overnight, then check the seal by pressing the top of each lid with a finger; the lid should not move up or down.
