Making a good tomato jam is all about high-quality tomatoes. Find the freshest, most flavorful tomatoes that are available. Ideally from your own home garden or the farmer’s market.
Ideally, you’d use an heirloom paste tomato, which will give a better yield. Paste tomatoes have less water in their tissues, so they’ll cook down less. Lacking paste tomatoes, flavorful heirlooms will also work wonderfully, but the yield will be lower.
This particular recipe has quite a bit of sugar, and that’s required to get the jam to set. With less sugar, the tomato jam just won’t set and you’ll have spiced tomato sauce instead, with obviously still too much sugar to be a decent sauce.
The spices included are flexible, including ginger, red pepper, cinnamon, and cumin resulting in a versatile (and incredible) tomato jam. Other good options include garlic powder, smoked paprika, and cloves (just a pinch).
Ripe tomatoes – Roma or plum are best
Brown sugar – for sweet, deep flavor
Fresh ginger – grated
Spices – salt, ground cumin, crushed red pepper, garlic powder
The basic process of making tomato jam isn’t all that different than making jam in general. This is an old-fashioned jam without pectin, which results in a much nicer texture than if you added boxed pectin.
The first step is to prep the ingredients: Chop the tomatoes and remove any loose seeds. Grate the fresh ginger. Set out a medium saucepot. Add all the ingredients. Bring to a boil. Then lower the heat and simmer for 1 – 1 ½ hours, stirring regularly, so it doesn’t burn on the bottom.
It should cook down a bit, but not reduce to the point of no moisture. Once the tomato jam looks thick and glossy, turn off the heat.
Place the tomato preserves in jars and either can, freeze, or refrigerate. Once it has been opened, keep stored in the fridge and use within 2-3 weeks.
The added lemon juice is there to balance out the sugar by adding acidity, but it’s also there to help preserve the jam. Tomatoes may seem acidic, but they’re actually borderline for canning. Do not reduce the lemon juice in this recipe if you’re canning.