This is delicious served with cold meats or sausages and will keep indefinitely. Use bottles that have contained shop-bought ketchup or you can buy the old-fashioned type 'pop' bottles from good kitchen shops.
Makes 3½ pints (2 litres)
This recipe is taken from Delia Smith’s Complete Cookery Course and Delia Smith’s Complete Illustrated Cookery Course.
8 lb (3.6 kg) plums or damsons
8 oz (225 g) currants
1 lb (450 g) onions, peeled and chopped small
2 pints (1.2 litres) distilled white vinegar
2 oz (50 g) sea salt
1 lb (450 g) demerara sugar
Tie the following spices in a piece of muslin or gauze:
6-8 dried chillies
1 tablespoon black peppercorns
1 tablespoon mustard seeds
½ oz (10 g) fresh root ginger, peeled and grated
½ oz (10 g) whole allspice berries
2 whole garlic cloves, peeled
First slit the plums with a sharp knife and remove the stones, then place the fruit into a preserving or large heavy-based pan and add the currants, onions and the bag of spices.
Add half the vinegar, bring to the boil and simmer gently, uncovered, for about 30 minutes or until the mixture is soft.
Now remove the bag of spices, place the contents of the pan in a liquidiser and blend until perfectly smooth – if necessary sieve as well. Then rinse out the pan and return the purée and bag of spices to it, adding the salt, sugar and the remaining vinegar.
Bring to simmering point and cook gently, uncovered, for 1½-2 hours or until the ketchup has reduced to approximately 3½ pints (2 litres).
Stir now and then to prevent sticking.
In the meantime prepare the containers by boiling the bottles and their tops. When the ketchup is ready pour it into the bottles while they're still hot, filling them to within an inch (2.5 cm) of the top.
Put on the tops immediately but screw them only half-way and if you're using the 'pop' type bottles push the top in but leave the lever up.
Next place the bottles in a larger deep pan (standing them on an upside down, heat-proof plate) and add warm water to within 1½ inches (4 cm) from the tops.
Bring the water to the boil and after 10 minutes transfer the bottles to a wooden surface and complete the sealing.