Processing of blackberries

More than 80% of the US production of blackberries in recent years has come from the Pacific Coast. The major blackberry-producing areas are Washington and Oregon. Blackberries grow on 2-yr old brambles or canes. Blackberries are very suitable for jam, marmalade and jelly as well as compote, sorbet, ice cream and parfait.

At the processing plant, the fruit is washed, inspected – to remove leaves, twigs, etc., and cooled to 32F. The fruit is held at this temperature until sold as fresh in retail sized baskets overwrapped with clear plastic or until it is processed.

Blackberries are harvested after ripening but before they have become soft and mushy. It is very unwise to allow the berries to become overripe, because they are then very susceptible to mold.

Blackberries should be thoroughly ripe when picked for freezing: otherwise they may turn red on freezing. The fruit is individually frozen in a cold air tunnel and packed in large metal cans with cap-type covers and held frozen. When the berries are to be used for producing jam and jelly, sugar is added to the cans so that the ratio of fruit to sugar is 5:1.

For producing jam, frozen fruit from cans is defrosted. The amount of sugar added results in a fruit to sugar ratio of 1:1. The pectin must be dispersed in the water before added to the mix. Water evaporated during the heating results in soluble solids content of 68%.

Blackberry jelly is produced by a similar process except that only clear juice is used, the amount of pectin is doubled, the soluble solids contents 65%, and the PH is adjusted to 2.9 – 3.2. Some blackberries are canned and heat-processed in water or light syrup for use as pie filling or in syrup for use in other desserts.
Processing of blackberries