Look for mangos that are football-shaped rather than thin or flat. The flatter mangos may be stringy. Avoid shriveled mangos. Mangos that are fuller and rounder usually have the deep color of a ripe peach instead of the yellowish-green that other varieties have. Avoid mangos with a sour or alcoholic smell. Because of their high sugar content, mangos will ferment naturally. When they begin to do so, they give off a distinctive odor that is a sure sign of a mango that is past its prime.
Ripen your mangos before eating them. To be sure that your mangos have fully ripened, check the area around the stem; if it looks plump and round, the mango is ripe. If there is any doubt, use your nose: with the stem-end up, smell the mango. A ripe mango will have a sweet, fruity aroma and be slightly soft to the touch, like an avocado or peach. A few brown speckles are also a normal indication of ripeness. Once you’ve ripened the mango, you can refrigerate it for up to four days.