Grapefruit makes a delightful, pale-coloured, fragrant marmalade. The fruit should be as sour as possible and with a thick skin. The amount of sugar given in this recipe is the amount traditionally regarded as necessary if the marmalade is to be kept for any length of time, but if you like marmalade very bitter, reduce the quantity of sugar by a quarter or even by a half.
2 lb. grapefruit
12 oz. lemons
4 pints water
6 lb. preserving or granulated sugar
Wash the fruit. Cut them in half and squeeze out and reserve the juice. Reserve the pips.
On a wooden board, chop the grape-fruit and lemons coarsely. Do not remove the pith as it adds to the texture and appearance of the marmalade.
Put the chopped fruit, the reserved juice and the water into a large preserving pan or saucepan. Tie the pips in a piece of cheesecloth and put them in the pan.
Place the pan over high heat and bring the mixture to the boil. Reduce the heat to low and simmer for 2 hours, or until the peel is soft.
Remove the bag of pips and press it against the side of the pan with the back of a wooden spoon to squeeze out as much juice as possible. Discard the pips. Add the sugar and stir until it has dissolved.
Increase the heat to high and boil the marmalade rapidly until setting point is reached. This takes about 20 minutes.
To test the marmalade for setting, remove the pan from the heat, put a spoonful of the marmalade on a cold saucer and allow it to cool. Setting point is reached when the surface of the marmalade sets and wrinkles when pushed with your finger. If setting point has not been reached, return the pan to the heat and continue boiling, testing every few minutes. Alternatively, use a sugar thermometer. When the temperature reaches between 220° and 222°F, setting point has been reached.
When setting point is reached, remove the pan from the heat and skim any scum from the surface of the marmalade with a slotted spoon. Let the marmalade stand for 5 minutes.
Using a jug or a ladle, fill clean, warm, dry jars to within 2-inch of the tops.
Put a small circle of waxed paper on top of each jar, taking care to leave no air bubbles between the paper and the jam.
Wipe the outside and inside rims of the jars with a warm, damp cloth to remove any stickiness. Cover with jam covers and fasten with an elastic band.
Label the jars and, when cool, store them in a cool, dry place.