To ripen avocados faster than you can say "guacamole," place the unripe fruit in a brown paper bag filled with a cup or two of flour. The paper bag trick is a tale as old as time, a long-known method of trapping the ethylene gas that avocados emit and using it to speed up ripening, but adding flour means that any excess moisture is going to be wicked up before it
While this may be good for making the best brown butter banana bread, it's not great if you're hoping to eat all those bananas while they're still fresh. Who knew that putting bananas in a bowl with other fruit could make them get ripe faster? Well, scientists for one, and now you do too. The reason behind this is due to the ethylene gas produced by the fruit and how it helps make all the other fruit in the bowl ripen faster.