Smelting

Smelting is a method of producing refined goods. It has the same idea as crafting: a player supplies acceptable ingredients, and receives a corresponding output. However, smelting utilizes furnaces, blast furnaces, or smokers, which have a unique interface: one input field for the object to be heated, a secondary input field for the fuel, and one output field for the final smelted product.

For example, two saplings (fuel) could be used to smelt one wood (input) into one charcoal (output). Raw food items can also be cooked using a campfire (without giving experience), while smokers and blast furnaces can smelt certain types of items twice as fast as usual at the cost of being unable to smelt any other items.

Usage and mechanics
To smelt with a furnace, an input material and a fuel must be placed into the top-left and bottom-left slots of it, respectively. The furnace begins to smelt on its own and continues to work if the menu is closed and the player leaves. The player can tell whether a furnace is working or not by seeing if the furnace is lit and the fire particle effects are appearing or not. When the furnace begins to smelt, it consumes one piece of fuel and the fire gauge fills. Once a piece of fuel begins burning, it cannot be stopped, unless the furnace is broken. While the piece of fuel burns, the fire gauge slowly decreases until it is gone, and the process repeats with the next piece of fuel. When all fuel is exhausted with material remaining in the input slot, the furnace stops, and the item is not smelted. If the input material is exhausted with fuel remaining, the fire gauge continues decreasing, wasting the remaining burn time left for the piece of fuel being burned, but no further fuel is burned if the input slot remains empty.

As items smelt, an arrow icon represents the smelting progress. Each smelting operation takes 10 seconds. When it completes, the smelted item is added into the output field. If the furnace runs out of fuel before the arrow is filled up, then the input is not smelted and the process rewinds at double speed.

If the player travels far enough to unload the chunk containing a smelting furnace, the smelting process pauses until the player returns. Smelting also pauses if a player leaves the dimension in which the furnace is located. If the player sleeps in a bed while a furnace is smelting items, the furnace's progress remains the same as if the bed had not been used and no additional time had passed. This is because when a player sleeps in a bed, no time actually passes; the game simply sets the time of day to morning.

If a player removes a smelted item from the output field, that player instantly receives experience for all the items smelted in that furnace, even items that had already been pulled out by a hopper.

Furnace variants
Items can similarly be smelted in a blast furnace or smoker:


 * The usage and interface for smelting with both blocks is the same as those of a normal furnace; however, each can use a subset of the furnace recipes. For the allowed recipes, they smelt items twice as fast as a regular furnace, but also use fuel twice as fast, so the same amount of fuel still smelts the same number of items.
 * A blast furnace can be used only to smelt ores, and the same metal items (tools, weapons, armor) that can be smelted by a furnace. Ores include both metal and gem ores, as well as ancient debris.
 * A smoker can be used only to smelt food items as listed below. The end result is what counts; chorus fruit is not included (because the result is not edible), but kelp is (because dried kelp is, even though raw kelp isn't).
 * Any other smeltable items (notably logs and cobblestone) can only be smelted in a regular furnace.

Using a campfire
Food items (the same items valid for a smoker) can also be smelted using a campfire. To do so, the player must a lit campfire, with any of the food items listed in the Recipes section in their hand. Fuel is not required; the campfire is able to cook items infinitely on its own. Smelting an item takes 30 seconds, three times the amount of time it would take if a furnace were used instead. However, as a campfire can hold up to four items and cook them all at once, it can potentially take 10 seconds less than what it would take for a furnace to cook 4 of said items. Once the campfire has finished cooking an item, it emerges from the campfire as an item entity. No experience points are granted.

Food
All food items can be smelted in a smoker.

Ores, minerals, and other materials
Some of these items can be smelted in a blast furnace.

The following additional ores can be smelted, but it's more efficient to mine them with an appropriate pickaxe. Mining them saves fuel and in most cases yields more product and experience, especially if the pickaxe has a Fortune enchantment. Smelting them, in contrast, allows obtaining the items via automation. The ore blocks themselves can be obtained only via the Silk Touch enchantment.

These ores can be smelted in a blast furnace.

Tools, weapons, and armor
These items can be smelted in a blast furnace.

For fractional experience values, first multiply this value by the number of smelted items removed from the furnace, then award the player the whole-number part, and if there is a fractional part remaining, this represents the chance of an additional experience point.


 * For example, when smelting 1 coal ore and removing the coal, the value is 0.1, so every ten coal you remove grants you one experience.
 * When smelting 5 sea pickles and removing all 5 lime dye, the value is 0.2 × 5 = 1, so this grants only 1 point.
 * The fractional experience stays within the furnace when the final total is not an integer, so the leftover experience is attributed to the next round of smelting.

Fuel
There are multiple fuels that can be used to smelt items. The type of fuel that should be used depends on the number of items in question.

For larger jobs, a single lava bucket or a block of coal can burn more items than can fit in the furnace—both input and output are limited to a stack of 64, but a block of coal burns 80 items, and lava can burn 100 items.

Hopper automation
The smelting process can be automated with hoppers on the top and bottom of the furnace. For larger smelting jobs, a third hopper on the side of the furnace can feed in fuel and, in case of lava being used as fuel, any empty buckets come out of the bottom hopper. This automatically feeds and empties the furnace so that different materials can be smelted in the same batch with no loss.

Whenever a hopper or minecart with hopper removes items from a furnace, any experience earned from cooking or smelting the removed items is saved in the furnace and awarded to the next player who manually removes an item from the furnace's output slot. This saved experience is in addition to that earned for the manually removed item(s).

Trivia

 * A wooden tool burns the same regardless of its remaining durability. A used-up tool is just as effective as fuel as a new tool.
 * "Smelting" is a broad term in the context of Minecraft while in the real world, smelting has a more precise definition.