Though they cans seem to be interchangeable fruity condiments, jams, jellies, and preserves have distinct textures and uses.

Making jam, jelly, or preserves is a creative process that balances simple ingredients with a touch of science. Each element serves a unique purpose, dictating texture, flavor, and even storability.

On the final day of the Eater Advent Calendar, we’re laying it (this banana jam, that is) on thick to upgrade our PB&Js and ...