Minecraft wiki entry for Transportation_methods, associated text: Hoppers are essentially item pipes that move items within them into the container it is pointing to. This can include other hoppers, allowing for hopper chains that can transport items quickly. The hoppers can also lead into chests, barrels, dispensers, and more to funnel items into storage rooms or to fuel redstone contraptions. This is a more pricey, slower, and less versatile system than water channels, with the prime downside being their inability to transport items upward (only to the side or downward). Therefore, hoppers are better used sparingly, only to take items from one container to another or from a water channel into a container.