Apples and quinces are rich in pectin, and an extract of these fruits can be used to gel fruit juices that are lower in pectin, as when making jams and jellies.
This recipe makes 1.75 l of liquid pectin.
Use 4½ kg organic quinces or pectin-rich apples, washed and sliced, including the peels, cores and pits. Place in a large cooking pot and cover with about 2 l of water. Cook, covered about ½ hour. Pour the contents into a jelly bag and allow to drip for 24 h. Return the strained juice to the pan and bring to a boil, then allow to simmer until reduced by about half. Strain the juice through a clean cheesecloth, and pour into hot, clean jars. Screw on the lids and turn the jars upside down for about 20 minutes.
To make jellies and jams, use 150 ml. of liquid pectin per kilo of fruit (or juice).