1. Start with 5 lbs tomatoes. Some people prefer plum or Roma, but we used basic red.
2. Wash six 6 oz jars and lids in soapy water. Place on a rack in a pot of hot water (so jars don't crack when filled).
3. Core tomatoes and chop into 1-inch pieces. Place in a pot with 3 cups turbinado sugar, 1/2 cup lemon juice, 2 tsp salt, 2 tsp grated ginger, 1/2 tsp ground cumin, 1/2 tsp ground cinnamon and tsp ground cloves.
4. Bring tomato mixture to a boil. Reduce heat to medium and simmer, stirring occasionally, until reduced by half and mixture registers 220 degrees on a candy thermometer, about 1 hours.
5. With a jar lifter, remove hot jars from water and bring water to a boil. Fill jars with hot jam, leaving inch of head space (a jar funnel helps). Wipe rims with a damp cloth, apply lids and hand-tighten bands to secure. Add jars to boiling water bath; boil for 20 minutes to seal.
6. Use jar lifter to transfer jars to a kitchen towel. After 12 hours, press on center of each lid to test seal. Lid should not pop up and down. If it does, boil again in water. Store in a cool, dark place for up to a year.