Sweetness defines jams—and sometimes overpowers them. To my mind, a jam that leaves a lingering coat of sugar on your tongue misses the point: savor the fruits of summer. Making fruit-forward jam is simple once you understand a bit of the science behind it.
Fruit needs three things to set, or thicken, a spreadable consistency: acid, sugar, and pectin. Think of the molecular interactions in fruit like a high-school romance: Pectin molecules are attracted to water, but water is attracted to sugar. If water and sugar “hook up,” the pectin molecules will bond—with a little encouragement from their best friend, acid—and the jam will thicken.
The traditional method of encouraging this interaction is to throw enough sugar into the batch to distract all the water molecules. But more sugar is not the only option. An acidic pectin, like one based on citrus fruits, is an effective matchmaker for pectin molecules. Another method to encourage pectin couplings is to reduce the pool of available water molecules.
Learn to make Any-Fruit Jam without Added Pectin and Any-Fruit Jam with Added Pectin