"Good tomatoes and balance are crucial. You need sugar for the kind of gooey, sticky quality we associate with jam; otherwise, all you’re producing is a tomato sauce, no matter how different the flavor is from the classic. Once you add that sugar, however, you need acid, because even though tomatoes are plenty acidic, they can’t counter all that sugar. I tried lemon juice, vinegar and finally lime, deciding that I liked the last best. Featured in: A Sweet Science Without Tomato Cans...."