Wash and peel the rhubarb. Cut into equal pieces. Cook together with the grenadine and fructose sugar. Heat moderate. Cook until 7/8 of the original weight of all ingredients.
Mash with a blender until a smooth consistency. Rub the mixture through a fine sieve and cool down.
Blend the mixture with the wodka and rhubarb juice.
Make the sorbet in the icing machine. Process for 20 minutes, take the mixture out of the machine and blend again. Continue the ice making for another 10 minutes. Store the sorbet ice in the freezer until needed.