In a large, uncovered saucepan, heat pomegranate juice, sugar, and lemon juice on medium high until the sugar has dissolved and the juice simmers. Reduce heat just enough to maintain a simmer. Simmer for about an hour, or until the juice has a syrupy consistency, and has reduced to 1 to 1 1/4 cups. Pour out into a jar. Let cool. Store chilled in the refrigerator.

If you want your pomegranate molasses to be sweeter, add more sugar to taste, while you are cooking it.