9 lbs (4 kg) quartered crabapples, with the skin and seeds
9 cups (2.25 litres) cold water
1/2 cup (125 ml) lemon juice
6 cups (1.5 litres) sugar
In a large saucepan, bring the crabapples, water, and lemon juice to a boil. Reduce the heat and simmer gently for 30 minutes, uncovered.
Line a colander with several layers of cheesecloth and place it over a large bowl.
Pour the crabapples in the colander and let drain for about 2 hours without crushing or squeezing the fruit. You should get about 2 quarts (8 cups) of juice. If the amount of juice obtained is different, count about 180 ml (3/4 cup) of sugar for each 250 ml (1 cup) of juice.
In the same clean saucepan, bring the crabapple juice and sugar to a boil. Attach a candy thermometer in the centre of the saucepan. Simmer until the thermometer reads 104 °C (219 °F). Skim carefully while cooking.