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Tomato Jam

Prep Time:

150 Minutes

Serves:

10 × 250 ml (8 oz) jars 10 half-pints = 5 pints = ~2.5 L / ~10 cups

Canning Method:

Hot Water Bath

Equipment

  • Large pot (15- 19 Liters or16–20 quart)

  • Water bath canner

  • Knife

  • Cutting board

  • Mandolin (Optional)

  • Large spoon or ladle

  • Canning funnel

  • Jar lifter

  • Lid lifter

  • Half-pint canning jars with lids and rings

  • Fine sieve or cheesecloth

  • Dishwasher or boiling water for jar sterilization

Ingredients

  • Tomatoes (whole): 2.7–3.6 kg (6–8 lb)

    • Target after prep/cook: ~6 cups prepared/cooked tomatoes (~1.4 L)

  • Lemon zest (finely grated): 1½ tsp (about 1 lemon)

  • Lemon juice: 60 ml (¼ cup) (bottled or fresh)

  • Sugar: 900 g (4½ cups) granulated sugar

    • (Or “cup-for-cup” Truvia-style sweetener; if using another sweetener form, follow its conversion.)

  • Powdered pectin (no-sugar-needed type preferred): 1 box

    • Optional firmer set: ~1.2 boxes (about 20% more)

Optional spices (for spiced tomato jam)

  • Ground allspice: ½ tsp

  • Ground cinnamon: ½ tsp

  • Ground cloves: ¼ tsp

Preparation

Use firm, ripe tomatoes. Roma/paste tomatoes are easiest (less watery). Avoid bruised or mushy tomatoes.

2. Peel tomatoes (blanch + shock)

  1. Bring a large pot of water to a boil.

  2. Add tomatoes in batches for 30–60 seconds.

  3. Transfer immediately to ice water.

  4. Slip skins off.

3. Seed + de-water (recommended for juicy tomatoes)

If using non-Roma types:

  1. Cut tomatoes in half.

  2. Squeeze/shake out most seeds and watery gel (no need to be perfect).

If using Roma/paste tomatoes, the source says you can mostly skip the aggressive de-watering.

4. Drain + dice

  • Put tomatoes in a colander to drain while you work.

  • Dice to about 1.25 cm (½ inch) pieces.

5. Prep jars + lids

Wash jars and keep hot (dishwasher sanitize cycle is fine).Warm lids in hot, not boiling water.

6. Simmer tomatoes

  1. Put diced tomatoes in a large pot.

  2. Heat slowly to a gentle simmer, stirring to prevent sticking.

  3. Cover and simmer 10 minutes.

  4. Measure ~6 cups (1.4 L) cooked tomatoes into a large saucepan/pot (the one you’ll use to finish the jam).

Optional: stir in lemon zest + spices now.

7. Add lemon juice + pectin; bring to full boil

  1. Add ¼ cup (60 ml) lemon juice.

  2. Stir in powdered pectin.

  3. Bring to a full rolling boil (can’t be stirred down), stirring constantly.

8. Add sugar; boil hard 1 minute

  1. As soon as it hits a full boil, add 4½ cups (900 g) sugar.

  2. Return to a full rolling boil.

  3. Boil hard for 1 minute, stirring constantly.

Remove from heat.

9. Test set (optional)

Cold spoon test.If too loose: add ¼–½ pack more pectin, boil 1 minute, retest.

10. Fill jars

  • Fill to 6 mm (¼ inch) headspace.

  • Wipe rims clean, apply lids, tighten bands fingertip-tight.

11. Process in water-bath canner

  • Jars covered by at least 2.5 cm (1 inch) water.

  • Half-pints/pints:

    • 0–1,000 ft: 5 min

    • 1,001–6,000 ft: 10 min

    • Above 6,000 ft: 15 min

12. Cool + store

Cool undisturbed 12–24 hours. Check seals. Label and store.

Sweet, glossy tomato jam that’s amazing with cheese, grilled sandwiches, eggs, burgers, or tortilla chips.

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