Put the rhubarb and water in a large pan.
Cut the lemon and orange rind into thin strips.
Pour the fruits over the rhubarb.
Put the lemon and orange rind in the pan, along with the cinnamon and bring to a boil over high heat.
Turn down the heat, stir and cover.
Let simmer for 10 minutes or until the rhubarb pieces are falling apart.
Pour the rhubarb mixture in a dampened jelly bag or in a strainer covered with two layers of cheesecloth.
Press on the fruits to extract all the juice.
You should get about 1.5 litre of liquid.
In a large pan, pour the rhubarb juice and add 125 ml of sugar for each 250 ml of juice.
Squeeze the lemon and orange, strain the juice and add to the rhubarb nectar.
Bring to a boil and let boil for 3 minutes.
Pour in sterilized jars.
Close tightly and put in the fridge.
Keep only a few weeks.
If you want to keep the nectar longer, pour the boiling nectar in sterilized jars; leaving a 5 mm space on top.
Screw the lids and place the jars in a large pot filled with boiling water to sterilize.
Boil for 15 minutes.
Keep cooking for 40 minutes.
Keep away from the light in a cool and dry place.
To serve, put some ice cubes in glasses and fill with equal parts of rhubarb nectar and club soda.
Garnish with orange slices and mint.