This is certainly a tart jam, and certainly a recipe from almost 6 months ago. Feel free to play with the amount of sugar–if you use Pomona’s Pectin, that is. Most pectins use sugar to help them gel. Pomona’s Pectin, however, uses calcium to gel. It is provided in the box it in which is comes. I therefore used Pomona’s usual instructions to make this, which I will outline here.
Tart Rhubarb-Orange Jam
Yield: About 4 Cups
2 lb. Rhubarb
2 t. Calcium Water (use instructions in Pomona’s box)
Zest and Juice of 1 orange
1/2 c. Water
3/4-1 c. Sugar
2 t. Pomona’s Pectin
Chop rhubarb into 1/2-inch pieces. Add rhubarb, calcium water, orange juice and zest, and water to a medium pot.
Mix together sugar and pectin in a bowl.
Bring rhubarb mixture to a boil, then add the pectin-sugar mixture. Stir while the mixture returns to a boil and pectin dissolves.
Can if preferred, or use within a few weeks.