Unlocked after producing your first log.
There are two sections in Fire Making. Fire and Rewards
There are two things here, heat, which is used for cooking and smelting advanced ores, and the Demon Butler.
Here is a table of heat production.
The demon butler is simply used to collect all of the rewards below.
When you reach certain amounts of heat you unlock rewards, these have various tiers and reward. Typical cooldown is 12 hours.
|Mining Pack||2500||Ores and Coal|
|Fishing Pack||25000||Raw Fish and Feathers|
|Cooking Pack||75000||Cooked Fish|
Each level or research upgrades this to a better version.
|Level||Cost||Effect||Time to research|
|1||500 Coins||Once you unlock a firemaking reward, it will be unlocked permanently, even if your heat level is reduced.||1 minute|
|2||100,000 Coins||Planks can be added to fire to generate even more heat.||1 hr|
|3||250,000 Coins||Every second, rewards have a very small chance to be instantly refreshed.||4 hrs|
|4||1 Milling Coins||Claimable firemaking rewards are doubled.||12 hrs|
|5||10 Million Coins||24 hrs|