There are many important things to remember when smelting items, to save both resources and time.
If there are fewer items than the fuel can burn, some of the fuel will be wasted. Accordingly, you will usually want to smelt things in multiples of 8 (when burning lumps of coal or charcoal), or occasionally 3 (2 wooden planks). For individual smelts, you can use sticks or saplings, 2 of which smelt 1 item. If your fuel source is plentiful, such as charcoal later in the game, you may not care about fuel wastage, so items can be smelted in any number.
When smelting items, it's best to choose a fuel that is most suitable for how much you are smelting, so that you can use up as few resources as possible. In these examples, the process is making green dye, but this works for any item. For slabs, wooden planks, and saplings, oak is used, but it does not matter what type of tree the item came from. Also, you can replace one of the slabs with a stick or sapling when burning slabs. Two slabs can be replaced with one of the following items or vice versa:
Fuels not shown are not ideal.
If you are doing 4-7 processes, start by doing them in groups of 3 until you have less than 3 processes left to do. Then you can do the rest using the appropriate fuel.
If you are doing 9-15 processes, the fuel depends on the exact number of processes you are doing.
- If you are doing 9, 12, or 15 processes, simply burn wood planks, wood slabs, or banners until all the processes are complete. For example:
You can do 12 processes more than one way.
If you are doing processes of 20 or 40 items (or another multiple of 20), you can use dried kelp blocks.
If you are doing 16-23 processes, the ideal fuel depends on the exact number of processes as well.
- If you are doing 16, 19, or 22 processes, start by burning 2 coal or charcoal.
- If you are doing 17, 20, or 23 processes, start by burning 1 coal or charcoal.
- If none of the above are true, just burn slabs, wood planks, or banners. You can also start by burning a blaze rod.
If you are doing 25-79 processes, do them in groups of 24 until you have less than 24 left to do. Then you can do the remainder with the appropriate fuel. Note that in extremely large projects you might be smelting more than a full stack. If this Is the case, you will need to do the following actions in the middle:
- Add more items to the input slot.
- Remove items from the output slot.
Using hoppers, you can automate these processes.
These are fuels to start with if you are doing large numbers of processes. Note that for lava buckets, you will need to remove the bucket before putting another fuel in. Set 0-19 items aside so that the number of items you are smelting is a multiple of 20.
To use lava efficiently, keep the remaining load of 36 or 16 items handy, and put it in during the middle third of the burn (after it has done that many, but before it exhausts the original stack). Remember to both refill the un-smelted items, and remove the smelted product. A despawn timer on a note block may help.
First, figure out if you can burn blocks of coal so that you would have a multiple of 100 items left to smelt, then burn lava buckets (which do 100 processes). Note that a group of 400 items can be done in multiple ways.
If this is not possible, you will need to do something else.
- If you are doing 120 or 140 processes:
- If you are doing 220 processes:
- After a piece of fuel has started burning, you cannot stop it from burning, though you can remove any unburnt pieces of fuel.
- When starting a new world, burning your wooden tools (once you have stone) is a quick way to make your first lump or two of charcoal. They each still smelt a complete item even if almost used up.
- Sleeping while smelting/cooking items will not speed up the process.