Hopper

The hopper is a block which moves items into and out of containers. When placed, its output end will attach to the clicked block. If an item falls into the top of it, it will store it in its own internal inventory of five item slots. However, if the hopper's output is attached to (or pointing at) a container with inventory slots (like a chest, another hopper, or a Minecart with Chest), it will transfer items from its inventory to the inventory of the attached block (or cart) at a rate of 2.5 items per second (8 game ticks, 4 Redstone ticks or 0.4 seconds per item). The hopper will also transfer items from the inventory of a container placed directly above it into its own inventory at the same rate. Even if the Hopper is drawing items from an inventory above it, and depositing it into another attached inventory, it will still transfer from the source inventory to the destination inventory at 2.5 items per second.

Behavior
Hoppers cannot be moved by pistons. Applying a redstone signal will stop the hopper from pushing out items, but they will still be able to accept new items. Despite not appearing as a solid block, attached blocks such as rails, levers, and redstone dust can be placed on top of hoppers.

The transfer rate of two hoppers connected sideways is 2.5 items per second, while vertically is doubled with 2 items being sent each time.

When a hopper is connected to the side of an object, a chest for this example, and there is another hopper directly underneath the first hopper, the bottom hopper has a higher priority. Whenever the hopper is outputting, an item in the first nonempty slot will be sent to the bottom hopper, and at the same time, another item (if there is any) from the first among the remaining nonempty slot will be sent to the chest. If you put a stack of items in the hopper, it will be divided evenly between the bottom hopper and the chest unless it is an odd number in which case the bottom hopper will get one more than the chest. If the hopper is initially empty and is taking input from another hopper sideways, all the items will go into the bottom hopper. If instead the hopper is being fed by another hopper above, then the items will be split evenly between the bottom hopper and the chest.

Testing with Comparators
If a hopper is the input to a redstone comparator, the comparator will output a redstone signal whenever there are any items stored inside the hopper. An empty hopper produces a power output of 0, a single item in a hopper produces a power level of at least 1, and the power level will increase depending on how you fill the 5 stacks of the Hopper (see Redstone Comparator for precise values) to a maximum power level of 15 at 5 full stacks.

Whether a comparator will activate when a hopper is simply transferring items from its input to its output depends on its configuration. For example, if three hoppers are arranged vertically feeding into each other, so that they are both pulling items from the hopper above and pushing items into the hopper below, a comparator off the middle hopper will activate; but if the middle hopper is faced to the side and powered, so that items are moving through it only because the hoppers above and below are pushing and pulling items into and out of it, a comparator off the middle hopper will not activate.

Interactions
Hoppers can remove items from and place items into the following:
 * Brewing Stands
 * Hoppers above the brewing stand will fill the ingredient slot, while hoppers to the side will fill the potion slots. Unlike furnaces, a hopper placed under a brewing stand will empty the brewing stand immediately, whether the potions are complete or not.


 * Chests
 * Large chests are treated as a single unit; one hopper placed on a large chest will fill up the whole chest.
 * Hoppers can only remove items from or place items into a chest if it can be opened.


 * Dispensers / Droppers
 * Items can be removed from as well as placed in dispensers/droppers.


 * Ender Chests
 * Hoppers do not interact with Ender chests. They will not push items into them or pull items out of them.


 * Furnaces
 * Items fed to the top of a furnace will fill the ore slot, items fed from any side will fill the fuel slot, and hoppers under the furnace will only take finished products (and emptied buckets from using lava as fuel). Removing items from a furnace in this way will not yield experience points.


 * Hoppers
 * A hopper fed by another hopper will take items from the latter even if the former is deactivated by a redstone signal: to stop the flow of items through two hoppers both of them must be deactivated.


 * Minecarts with Chest / Hopper
 * Hoppers will fill minecarts with chests or hoppers if they are pointing at them and are not separated by another block. Hoppers can also take items from minecarts above them; rails can be placed directly on top of hoppers by aiming at a nearby block or holding the sneak key (default ), to make unloading stations. A hopper will not unload a minecart which is on a Detector Rail above the hopper, because the detector rail will power the hopper.


 * Trapped Chests
 * Identical to chests (see above), except that interaction is blocked while the chest is open, as it emits a redstone pulse and powers the hopper.

Connecting

 * A hopper will connect to the block at which you point, and only that block (does not automatically connect to others).
 * If you destroy the block to which the hopper was connected, it stays pointing to the original location; useful for transferring into minecarts via their sides.
 * To get a hopper to connect to a block with an inventory, sneak and click the block.
 * You can deactivate a hopper with a redstone signal, but note that another (active/unpowered) hopper beneath it can still take items from it.
 * If you place a hopper by clicking on the bottom face of the block, the hopper will not point up, but down instead, because you can't input upwards. This can be solved by using a Minecart with a Hopper and sending it up along a rail.
 * When using hoppers to remove smelted items from a furnace, you aren't granted experience.

Trivia

 * A hopper is a type of chute used in industrial processes that incorporates a limited storage capacity.
 * Hoppers do not automatically connect to the nearest storage block. Instead, you must hold the sneak key while placing it on the storage block.
 * The hopper was used in the Dropper recipe until the 13w04a snapshot.
 * If you set fire on top of a hopper, the fire can't be seen, but this is only if there is no block adjacent to the fire (useful for chimney smoke)
 * Hoppers are transparent to light sources.
 * Hoppers pulling items from a furnace will prevent getting experience from the smelting of the items
 * Chickens can easily become stuck inside hoppers, and once inside are difficult to interact with, but still produce eggs. A hopper filled with chickens and attached to a dispenser with a 5-clock results in a compact automatic chicken machine.
 * If a hopper is connected to a dispenser while the dispenser has an activated redstone trail attached to it, then the hopper won't drop items into the dispenser
 * Items can be accepted through a half slab of any kind. (This has not been fully tested and needs further guidance.)