Jelly Making: Test for Pectin

Pectin is the substance in fruit that when combined with fruit acid and heated with sugar, causes the fruit juice to "jell." Some fruits contain little or no pectin, but most fruits and some vegetables contain it in varying amounts, and it is more abundant in underripe fruits than fully ripe fruits.

The Test
Mix 1 tablespoon of cooked unsweetened juice with 1 T grain alcohol. Wood or denatured alcohol may be used but should not be tasted as they are poisonous.

Juice rich in pectin will form a large clot.

Juices moderately high in pectin will form a few smaller clots.

Juice very low in pectin will form small flaky sediment.

These fruits are rich in acid and pectin:
Sour apples
Blackberries, sour
crab apples
cranberries
currants, red
gooseberries
grapefruit
grapes
lemons
oranges, sour
plums (most varieties)

These fruits are rich in pectin but low in acid
Sweet apples
Quinces

These fruits are high in acit but low in pectin:
Apricots
Cherries
Pineapples
Strawberries

The following fruit is low in both acid and pectin:
Raspberries
Elderberries
Peaches
Overripe fruits