The best way to store ripe bananas indoors is in a cool, dark place, ideally unbagged and away from other fruits. You can also wrap the stems in plastic wrap to slow down ripening.
Bananas release ethylene gas, which accelerates ripening. Storing them in a closed container traps this gas, causing them to ripen faster. Therefore, avoid storing them in airtight containers or plastic bags unless you're specifically trying to speed up the ripening process. A cool, dark environment, like a pantry or a shaded countertop, helps slow down the production of ethylene gas. Separating bananas from other fruits, especially those that also produce ethylene (like apples and avocados), will further extend their shelf life. Wrapping the stems, where much of the ethylene is released, in plastic wrap can also significantly delay ripening. This creates a barrier that reduces the amount of gas released into the surrounding environment.
If your bananas are ripening too quickly, you can peel and freeze them for later use in smoothies, banana bread, or other baked goods. This prevents waste and allows you to enjoy them at your convenience.