My rhubarb is huge, and ready to eat now! I cooked some for a pie and made some extra juice to make this agar agar.
1 l water
200 g sugar
a few drops of lemon
600 g rhubarb stalks, cleaned and cut into pieces
2 tsp agar agar
Boil the water, sugar and lemon juice. Add the rhubarb and cook until it starts to froth. Drain and use the rhubarb to make pies (or eat by itself). Collect the juice and bring back to boil. Add the agar agar and simmer for 3 minutes.
Pour into a square or rectangular container. Cool. Cut in to squares and store in the fridge. Very refreshing and with a delicate but distinctive taste.