Custard Apples Grown by Brian Keating in rich but fragile volcanic soils at Duranbah. Brian grows Pink Mammoth and African Prides (with the sharp knobbly surface) in his slice of heaven. He maintains a large nature reserve to help prevent erosion which can be a problem in these soils and provide habitat for local species.Pinks Mammoth are larger and sweeter than the African Prides. A custard apple is ripe when you gently squeeze it and it gives slightly under your hand. To accelerate the ripening process put the fruit in a paper bag with a banana on you kitchen bench. Custard Apples are only eaten when soft, and only the flesh is eaten. To eat, simply cut in half and scoop out the white flesh. Once ripe, custard apples can be stored in the fridge for up to 3 days. Once the skin has gone purple or black, they have passed their best eating quality.