Rhubarb compote

Rhubarb compote
(Makes 6 - 8 jars of 220 ml each)
2.5 kg rhubarb
250 g sugar
1 cinnamon stick
1 organic lemon
2 tsp. cornstarch
Rinse the rhubarb thoroughly, peel and cut into chunks of approx. 2 cm. Place in a large pan with the sugar and leave to stand for 2-3 hours to draw out the juice. Add the cinnamon stick and bring to the boil. Cover and simmer over a low heat for 10-15 minutes, stirring occasionally.
In the meantime, rinse the organic lemon under hot water, rub dry and grate off a little of the zest with a fine grater. Combine the cornstarch with a splash of cold water and stir until smooth (important to avoid lumps!), and mix into the rhubarb compote. Finally, add the lemon zest and cook over a low heat for a further 3 minutes, stirring continuously. Afterwards, leave to cool for 20-30 minutes, remove the cinnamon stick and sweeten the rhubarb compote as desired, e.g. with sweetener. Enjoy immediately or preserve for cold days.

Now the preserving (the real nitty-gritty!) can begin:
Place jars and matching lids in the desired sizes in a water bath and boil gently for 5 minutes to sterilise. Remove the jars using a pair of tongs and drain and dry on a clean dishcloth upside down.
Spoon the rhubarb compote into the jars and seal tightly with preserving ring, lid and spring clips.
Place the jars in the preserving boiler and fill with enough water that the jars are 3/4 immersed (the jars can also be stacked - it is possible to immerse them completely). Heat the water to 80 °C. When this temperature is reached, preserve for 30 minutes.
Remove the jars from the preserving boiler, place on a dishcloth and leave to cool completely. Then remove the spring clips and do a “lid test”: Pick the jar up by the lid - and if it remains tightly shut, the jar is hermetically sealed.
If stored in a dark, cool place, the preserved rhubarb compote will keep for up to 6 months. Before eating, do another “lid test” to ensure that the compote is still edible.