From berries and peaches to rhubarb, this versatile jam recipe transforms fresh fruit into deliciously sweet preserves. Once macerated, the fruit mixture is cooked into a glossy, jewel-toned jam.

I spent the rest of that year learning the basics of how to preserve — not just jam, but also pickles, relishes, boozy fruit, sauces, canned tomatoes, and all the rest. The next year I became ...