Rhubarb Peel Syrup
250 g/ 8.8 oz rhubarb peel
1 kg/ 35.2 oz granulated sugar
10 g/ 2 ¼ teaspoons citric acid
1 liter/ 4.2 cups/ 33.8 fluid oz water
Wash rhubarb thoroughly before peeling it. Measure the peel and place it in a pan. Add the rest of the ingredients and bring everything to a boil. Turn the heat down and let the syrup cook, uncovered for 30 minutes. If you make the double amount give it 5 more minutes cooking time. Take the syrup off the heat, let cool down and keep in the fridge or cellar for 24 hours.
Strain the syrup and discard the peel. Pour the syrup back into the pan, bring to a boil and simmer, uncovered for 10 minutes. Pour into the sterilized bottles and seal.