The goal: Jam that drops from a spoon but stays on a biscuit (at least until I eat it, which is usually less than T minus ten seconds).
As a jam maker from way back, I never really embraced commercial pectin. This had more to do with my end results than any preconceived notion of its application. Sometimes I’d end up with jam that resembled a giant jello shooter or a gum drop in a votive. I would call it slicing jam or fruit gel in a jar. When I spied my homemade gifts of jam from 1998, and 1999, lining the shelf of a friend’s post-millennium pantry, I had to admit that the only thing denser than my jam was my denial of its shortcomings.
Tip One: With a decade of jam making under my ample belt, I’ve found the secret to thickening up runny low-pectin fruit jams: add an apple or two. Pectin is a naturally occurring thickener found in most fruits, though levels vary greatly. For example, apples are high pectin fruits, cherries low. When I make jam out of a low pectin fruit like sour cherries, I add a peeled, grated apple to the preserving pot to boost the thickness factor. Because the subtle flavor of the apple usually takes a back seat to the sour cherry, it’s a fruit marriage made in heaven where the strongest flavor wins. (No 50-50 here.)
Tip Two: Another way to help thicken your jam is to put the undercooked fruit jam in a fine mesh sieve and drain the liquid. Return the liquid to the preserving pot, simmer until syrup thick then add the cooked fruit mixture back, stir and bottle up.
Here’s a list of low and high pectin fruits:
High Pectin Fruits
- Apples (tart, under-ripe have more pectin)
- Blackberries (also more pectin if slightly under-ripe)
- Grapes (Eastern Concord)
Low Pectin Fruits
- Apples (overripe)
- Sweet and Sour Cherries
- Plums (Italian)