They may look unappetizing with lots of brown spots, but overripe bananas are usually fine to eat, and even better for cooking. Ripe bananas eventually spoil after about five days left at room temperature; they stay good another five to seven days in the refrigerator although their skins turn completely black. And if you take the skins off, for easy defrosting, overripe bananas remain edible and good for cooking up to three months in the freezer.
Ripeness, Bruises and Spoilage
As bananas ripen, their starch turns to sugar, their flavor changes from starchy to sweet and their texture changes from slightly chalky to mushy, even though the flesh stays white. These ripe bananas are safe to eat.
A bruise on the banana appears less as small spots on the peel and more like a single, larger, brown patch. Inside, the banana flesh will also be brown in the bruised area. Simply cut out that area and eat the portions of the banana that remain white.
Bananas become spoiled when they sit at room temperature for too long or if bruised spots inside the banana have provided an environment for bacteria to grow. If the banana flesh inside has small white spots on the browned bruised portions, or if the flesh has turned somewhat runny, throw away the whole banana.
When you cook overripe bananas in a skillet, their sugars caramelize, and they gain a nutty, deep flavor. For the classic dessert bananas Foster, saute banana slices in butter and honey for about 3 minutes, then pour in about 1/4 cup of rum for each 4 bananas, flame the liquor and pour the concoction over ice cream. For crispy, fried bananas, coat slices in a batter, in bread crumbs or in shredded coconut, and cook them in 1/2 to 3 inches of oil until they turn golden, about 1 to 2 minutes on all sides.
Baked Goods, Pancakes and Waffles
On her website, Anne Byrn, author of The Cake Mix Doctor, recommends adding anywhere from one to three very ripe, mashed bananas to any boxed cake mix to add flavor and moistness. Byrn also adds 1 cup of mashed bananas to muffin recipes without any adverse effects to the final products. You can do the same thing with pancakes and waffles, adding from one to two mashed bananas to any recipe. Overripe bananas work even better in these recipes because they bring more sweetness and flavor.
Smoothies and Ice Cream
Add one or more overripe bananas, either frozen or not, to smoothies of any flavor. Or, turn frozen bananas into faux ice cream with the help of a blender or food processor. Pulse small pieces of frozen bananas until they turn from crumbly to gooey to a smooth texture resembling soft-serve banana ice cream. Eat the ice cream immediately or freeze it until it hardens.
References and ResourcesStill Tasty: Bananas -- Fresh, Raw, Whole
What Einstein Told His Cook 2; Robert L. Wolke
Saveur: Fried Bananas (Kluai Khaek)
The Cake Mix Doctor: Banana Cake
The Kitchn: How to Make Creamy Ice Cream With Just One Ingredient!