Ketchup: Australian Tomato Sauce Simmered with Ginger and Wine Vinegar

Steps

1. 1Prepare the vegetables and the jars

   Chop the onions finely, crush the garlic and grate the ginger. Chop the tomatoes coarsely, keeping their juice on the board, and finely chop the chilli if you are using it. Wash the glass jars and lids, boil them to sterilise, and let them dry completely on a clean towel. Everything is ready when the jars are bone-dry inside and the vegetables sit in separate piles by the stove.

2. 2Soften the onion in olive oil

   Warm the heavy saucepan over medium heat and add the olive oil. Add the onion and cook, stirring often, until it is translucent and soft enough to crush against the pan with the spoon. Keep the heat moderate so the onion stays pale. The onion is ready when it is glossy and floppy, with no brown edges.

3. 3Cook the garlic, ginger and chilli until fragrant

   Add the garlic, ginger and chilli to the softened onion. Stir constantly so nothing sticks to the hot base. Burnt garlic turns the whole batch bitter, so lower the heat if anything starts to darken. Move on as soon as the kitchen smells strongly of ginger and garlic.

   Keep the onion pale

   Browned onion makes brown sauce. Any colour you put on the onion and garlic here shows up in the finished bottle as a dull, muddy red, so take the heat down rather than rushing this stage.

4. 4Add the tomatoes, sugar, vinegars and spice

   Tip in the tomatoes, coriander, sugar, both vinegars and salt all at once. Stir to dissolve the sugar and lift anything stuck to the base. Raise the heat and bring the pan to the boil. The pot is ready for the long simmer when bubbles break across the whole surface and the sharp smell of vinegar rises with the steam.

5. 5Simmer uncovered until thick

   Turn the heat down low and leave the lid off. Simmer for about 40 minutes, scraping the base of the pan with the wooden spoon from time to time so the sugar does not catch. The tomatoes will slump and fall apart, and the sauce will darken and thicken. It is done when a spoon drawn across the base leaves a trail that shows the pan for a moment before the sauce slowly closes over it.

6. 6Cool, then blend until smooth

   Take the pan off the heat and let it stand for 15 minutes. Hot sauce spits out of a blender, so this rest protects you as well as the machine. Blend the sauce in batches, filling the jug only partly each time. The sauce is ready for the sieve when it pours as a smooth purée with no visible lumps of tomato.

   Hot sauce and the blender

   Blend in small batches with the lid held down under a folded cloth, and never fill the jug with sauce straight off the boil. Sugary tomato sauce clings to skin and burns badly.

7. 7Push the sauce through a fine sieve

   Set the fine-mesh sieve over a large heatproof bowl. Pour in the purée a ladleful at a time and press it through with the back of the wooden spoon. Scrape the underside of the sieve into the bowl, where the smoothest sauce collects. Discard the skins, seeds and fibres left behind once only a dry, pulpy mat remains in the mesh.

   Strain twice for a bottle-smooth pour

   If the sauce still feels grainy on a fingertip, pass it through the sieve a second time. Skins and fibres make the sauce gritty and clog the neck of a bottle.

8. 8Bring the strained sauce back to the boil

   Pour the strained sauce back into the rinsed saucepan. Set it over medium heat and stir constantly, because the smooth sauce catches more easily than the chunky one. Keep the jars close by with the funnel ready. The sauce is ready to jar when it bubbles steadily across the surface and is hot all the way through.

9. 9Fill the hot jars and seal

   Pour the hot sauce through the funnel into the sterilised jars, working quickly so both sauce and jars stay hot. Seal each jar straight away with its lid. Leave the jars to cool on a folded towel. When they are cold, label and date them, then put them in the refrigerator.