Cool off with this unique rhubarb infusion. This vegetable carries the tart bite of lemons and pairs well with sweet fruits like oranges and strawberries. It contains vitamins A, C and fiber as well as lutein and zeaxanthin, two phytochemicals that fall into the carotenoid family and have antioxidant properties.
In large, stainless steel or other non-reactive saucepan, combine rhubarb and water. Cover and bring to boil over medium-high heat. Reduce heat and simmer 15 minutes. Set covered pot aside to steep for 10 minutes.
Set large strainer over bowl. Pour contents of pot into strainer and drain liquid into bowl. Using back of wooden spoon, press very lightly on rhubarb, just to extract liquid that drains easily. Pressing too firmly will make infusion cloudy. Discard pulp. Pour liquid, about 4 cups, into jar or other container, preferably glass, and let sit until room temperature, then cover and refrigerate for up to 2 days.
To serve Refresher, measure 3 cups rhubarb infusion. Pour 1/2 cup into pitcher, add agave, and stir until combined. Pour in remaining rhubarb infusion and orange juice. To serve, divide Refresher among 4 ice-filled, tall glasses. Garnish each glass with mint sprig, if using. For single serving, in a glass, combine 1/4 cup rhubarb infusion with 1 tablespoon agave, and then add remaining 1/2 cup infusion, 1/4 cup orange juice and ice.