Sweet Chilli Tomato Sauce Recipe | Easy DIY Chilli Relish for Canning

This sweet chilli tomato sauce brings bright tomato flavor, gentle heat, and a glossy, jammy finish you’ll want to spoon over everything. Think of it as a cross between ketchup and chilli jam: tangy, sweet, and just spicy enough. It’s an easy weekend project and a brilliant way to turn a glut of tomatoes and chillies into jars of homemade relish you’ll use all year.

I’ll walk you through a reliable small-batch method that scales up for canning. We’ll cover the exact ingredient ratios, simmer time for the right thickness, and how to safely water-bath can your sauce so it stays shelf-stable. Expect simple steps, pantry-friendly ingredients, and a result that tastes miles better than store-bought.

Why This Sweet Chilli Tomato Sauce Works

Balanced flavor: The right mix of tomatoes, sugar, vinegar, and salt creates a sweet-tangy base with a warm chilli kick.
Perfect texture: A slow simmer reduces the sauce to a glossy, spoonable relish that coats burgers, sandwiches, and grilled meats.
Canning-safe acidity: Vinegar and tomatoes provide the acidity you need for safe water-bath canning.
Flexible heat level: You can adjust chilli type and quantity without changing the process.
Batch-friendly: Make a small jar today, or scale it for a case of pint jars.

Ingredients

Yields about 4 half-pint (8 oz) jars

4 pounds ripe tomatoes (Roma or plum tomatoes reduce best; core and roughly chop)
6–8 fresh red chillies (Fresno or red jalapeño for medium heat; deseed for milder)
1 large onion (yellow or white, diced)
6 cloves garlic (smashed)
1 1/2 cups white sugar (or split white and light brown for deeper caramel notes)
1 cup apple cider vinegar (5% acidity; you can use white vinegar for a sharper bite)
2 teaspoons kosher salt
1 teaspoon paprika (sweet or smoked)
1/2 teaspoon ground cumin (optional, for warmth)
1 lemon (zest and 2 tablespoons juice, optional but brightens the finish)

Tools You’ll Need

Large nonreactive pot (stainless steel or enameled)
Immersion blender (or countertop blender)
Wooden spoon and ladle
Candy or instant-read thermometer (helps track the simmer; optional)
Canning jars, lids, and rings (sterilized)
Water-bath canner or large deep pot with rack
Jar lifter and funnel (for safe, tidy filling)

How to Make Sweet Chilli Tomato Sauce

1) Prep the produce

Core and chop tomatoes. You don’t need to peel; the blender will smooth everything out.
Stem chillies. For medium heat, leave some seeds. For mild, remove most seeds and membranes.
Dice onion and smash garlic.

2) Start the base

Add tomatoes, chillies, onion, and garlic to a large pot. Stir in sugar, vinegar, salt, paprika, and cumin.
Bring to a boil over medium-high heat, then reduce to a lively simmer. Stir every few minutes so nothing sticks.

3) Blend smooth

After 25–30 minutes, when tomatoes break down and onions soften, blend with an immersion blender until smooth and glossy.
If using a countertop blender, work in batches and vent the lid. Return the purée to the pot.

4) Reduce to a relish-like thickness

Simmer uncovered 25–40 minutes more, stirring often, until thick and jammy.
Doneness cues: A spoon dragged across the bottom leaves a brief trail; a droplet mounds on a cold plate instead of running.
Stir in lemon zest and juice during the last 5 minutes for a bright finish.

5) Taste and adjust

Add a pinch more salt for pop, extra sugar for balance, or a splash of vinegar if it tastes flat.
Keep the total liquid minimal now; you want a thick, clingy sauce.

How to Store and Can the Sauce

Short-term storage

Cool completely, transfer to clean jars, and refrigerate up to 4 weeks.
Freeze in freezer-safe containers for up to 6 months. Leave headspace.

Water-bath canning (shelf-stable)

Sterilize jars: Wash jars, lids, and rings. Keep jars hot in simmering water.
Prep canner: Fill a canner or deep pot with a rack and enough water to cover jars by 1–2 inches. Bring to a simmer.
Heat the sauce: Keep it hot but not scorching.
Fill jars: Use a funnel to ladle hot sauce into hot jars, leaving 1/4-inch headspace. Bubble, wipe rims, apply lids and rings fingertip tight.
Process: Lower jars into boiling water. Process for 15 minutes (half-pints and pints), adjusting for altitude as needed.
Cool: Turn off heat, rest 5 minutes, then remove jars. Let sit undisturbed 12–24 hours.
Check seals: Lids should be concave and not flex. Label and store in a cool, dark place for up to 12 months.

Altitude adjustments

1,001–3,000 ft: +5 minutes
3,001–6,000 ft: +10 minutes
6,001–8,000 ft: +15 minutes
8,001–10,000 ft: +20 minutes

Why You’ll Love Keeping This Relish Around

Weeknight upgrade: A spoonful wakes up eggs, roasted veggies, chicken, and tofu.
Sandwich secret: Spread on grilled cheese, burgers, wraps, or breakfast sandwiches.
Party-ready: Serve with a cheese board, samosas, or crispy potatoes.
Giftable: Tie a label on a jar and you’ve got the perfect homemade present.
Zero waste vibes: Use garden tomatoes and spare chillies before they fade.

Mistakes to Avoid

Skipping the acid: Don’t reduce or replace vinegar with low-acid liquids if you plan to can.
Rushing the simmer: High heat can scorch the bottom. Keep a steady, bubbling simmer and stir often.
Over-thickening: The sauce thickens more as it cools. Stop when it looks slightly looser than your goal.
Using unripe or watery tomatoes: You’ll need to cook down much longer and the flavor suffers. Choose ripe, meaty tomatoes.
Poor jar prep: Cold jars plus hot sauce can crack. Keep jars hot before filling and leave proper headspace.

Tasty Variations

Garlic-chilli ketchup: Add 1 tablespoon tomato paste and 1 extra clove of garlic for a ketchup-like thickness and depth.
Smoky chipotle: Swap half the fresh chillies for 1–2 chipotles in adobo and use smoked paprika.
Ginger-lime zing: Add 1 tablespoon grated fresh ginger and finish with lime zest and juice instead of lemon.
Tamarind tang: Stir in 1 tablespoon tamarind concentrate for sweet-sour complexity; reduce vinegar slightly to taste.
Low-sugar route: Use 3/4 cup sugar and add 1 finely diced red bell pepper for body. Simmer longer to concentrate.

FAQ

How spicy is this sauce?

With Fresno or red jalapeño, it lands medium. Deseed for mild. Use serrano or a touch of bird’s eye for hotter.

Can I use canned tomatoes?

Yes. Use two 28-ounce cans of crushed tomatoes. Simmer 10 minutes longer to reduce excess liquid.

Do I need pectin?

No. Tomatoes, sugar, and a good simmer give you a naturally jammy texture.

Can I reduce the sugar?

You can, but expect a thinner, tangier sauce. Don’t cut vinegar for canning safety; adjust sweetness after opening if needed.

How long does it last after opening?

Refrigerate and use within 3–4 weeks. Always use a clean spoon.

My sauce separated in the jar. What now?

Give it a vigorous stir or shake after opening. Separation happens when the reduction wasn’t quite finished; the flavor stays great.

What if I don’t have a canner?

Use a deep stock pot with a rack or folded towel at the bottom. Keep jars covered by at least 1–2 inches of boiling water.

Final Thoughts

This sweet chilli tomato sauce turns simple ingredients into a sticky, shiny relish that makes every bite brighter. Make a batch on a lazy afternoon, tuck a few jars in the pantry, and you’ll always have a bold, tangy-sweet finish within reach. Once you taste it on crispy potatoes or a gooey grilled cheese, you’ll wonder how your fridge ever managed without it.