Apple trees are known for their ornamental blossoms and tasty autumn fruit. Although most fruit from crab apple trees is too small to harvest and normally left to the birds, some trees produce fruit large enough for you to use. The difference between a traditional apple and a crab apple is the size -- crab apples are less than 5 cm (2 inches) in diameter and resemble large cherries.
Although you may be able to tell if a traditional apple tree is ready to harvest based on the taste, keep in mind that crab apples are more bitter than regular apples. Instead of tasting the fruit, cut the fruit through the centre "equator" line, and look at the seeds. Crab apples are ready to harvest when the seeds are brown and firm or when the fruit turns a reddish brown colour, and the fruit is soft. Unripe crab apples are hard and bitter like a lemon.
Research the type of crab apple tree you have to determine the normal size of the fruit at maturity. For example, Centennial crab apples look more oval and reach about 4 cm (1 1/2 inches) at maturity, whereas the Everest crab apple resembles the look of a cherry and is about the size of a 50p piece at maturity. Wickson crab apples work well for hard ciders, although some fruit on the tree grows larger than 5 cm (2 inches) in diameter. Although most crab apple trees are harvest-ready in the autumn, the exact time depends on the type of tree and summer weather conditions.
Don't try to harvest each crab apple by hand -- it takes too long. Instead, place a tarpaulin or plastic sheet beneath the tree and shake the branches until the fruit drops. Sort through the dropped fruit to eliminate any that is rotten or over-ripe.
Crab apple uses
Most crab apples have a tart flavour compared to normal, sweet apples. However, you can use crab apples in apple butter as well as jams and jellies. Adding some crab apples to cider gives the drink dimension and more body than traditional cider.