Why Fuel Matters
Fuel is the heat budget behind every furnace-based production line. If that budget runs short, crucibles, smelters, and other heated devices stop even when their recipe inputs are waiting on the belt.
In Alchemy Factory, fuel is not a speed upgrade. A stronger fuel item supplies more stored heat, which means fewer items must be delivered and burned to sustain the same machines. Production speed comes from the device and recipe; fuel simply keeps the heat available.
This makes fuel planning important from the first charcoal setup through late-game potion-powered factory floors. A line can look perfectly balanced on paper yet fail because its fuel delivery cannot match its heat consumption.
Fuel Items and Heat Values
Every fuel item has a heat value. When a heating device burns an item, it uses that stored heat over time to support itself and the devices placed on it. Higher-value items are denser on belts and need less frequent delivery.
| Fuel item | Heat value | Typical role |
|---|---|---|
| Plank | 20 | Simple early fuel |
| Charcoal | 40 | Refined wood fuel |
| Charcoal Powder | 48 | Compact early processing fuel |
| Coal | 540 | Mid-game dense fuel |
| Coke | 600 | Refined coal fuel |
| Coke Powder | 660 | Strong general-purpose fuel |
| Black Powder | 6,000 | High-density advanced fuel |
| Blast Potion | 24,000 | Late-game high-demand fuel |
| Panacea Potion | 320,000 | Extremely dense end-game fuel |
Other burnable items include Logs with 2,000 heat and Coal Ore with 30,000 heat. Their large listed values do not automatically make them the best choice, because they may be more valuable as inputs to a refining chain than as direct furnace feed.
Fuel can be understood in three broad groups:
- Raw inputs, such as logs and coal ore, can be burned directly but may sacrifice valuable processing potential.
- Refined solid fuels, including charcoal, coal, and coke, offer a practical balance of density and supply cost.
- Powders and potions provide the most convenient belt density for larger operations, especially where many machines share a fuel route.
The right choice depends on how much heat a section needs, what materials are available, and whether the fuel line can sustain itself before supplying the rest of the factory.
Calculating Heat Demand
Heat is measured as a per-second requirement. To estimate alchemy factory fuel consumption, add the heating device’s own heat use to the requirements of every active device it supports.
A standard furnace consumes 1 heat per second while operating, including when it has no active consumer. A blast furnace uses 4 heat per second. Heat-consuming devices placed on top add their own demand.
| Setup | Heating device demand | Consumer demand | Total heat per second |
|---|---|---|---|
| Furnace only | 1 | 0 | 1 |
| Furnace with 1 crucible | 1 | 4 | 5 |
| Furnace with 2 crucibles | 1 | 8 | 9 |
| Furnace with 3 crucibles | 1 | 12 | 13 |
| Smelter on a furnace | 1 | 9 | 10 |
For example, three crucibles on one furnace need 13 heat per second: 1 from the furnace and 12 from the three crucibles. If a plank provides 20 heat, that setup burns roughly one plank every 1.54 seconds while all three crucibles are working.
Sharing a heating device improves efficiency because its base heat cost is shared. Three separate furnace-and-crucible pairs need 15 heat per second total, while three crucibles on one furnace need 13. The savings are real, but they do not make the added crucibles free; each consumer still adds its full heat requirement.
Use this quick planning process before building:
- Count every heated consumer in the production group.
- Add each device’s heat-per-second demand.
- Add the furnace or blast furnace demand.
- Compare the total with the heat delivered by your chosen fuel over time.
- Include extra production capacity so the line can recover after belt gaps or temporary demand spikes.
A heating device finishes the currently burning fuel item before taking the next one. That behavior makes a steady input preferable to occasional large bursts, particularly in busy lines with several consumers.
Building a Reliable Fuel Network
Early factories can use short, local fuel loops. A charcoal or charcoal powder line placed beside a few furnaces is easy to understand and prevents transport from becoming another problem to solve.
As output grows, decide whether a fuel line should be dedicated or shared. Dedicated production is often the safer option for an important product aisle: the fuel source serves its own furnaces first, and any excess can be exported elsewhere. A shared main belt is more flexible, but one expanding department can quietly starve every other department connected to it.
| Strategy | Best use | Main advantage | Main risk |
|---|---|---|---|
| Local fuel loop | Small early setups | Short belts and simple troubleshooting | Repeated infrastructure |
| Dedicated aisle fuel | Important machine group | Prevents competition with other lines | Can leave excess fuel isolated |
| Central fuel belt | Mixed factory areas | Easier distribution and expansion | A shortage affects many systems |
| Perimeter fuel route | Organized larger factory | Convenient access across multiple areas | Requires careful throughput planning |
Coke powder is a useful mid-game baseline because it has far more heat per belt slot than charcoal powder and can support substantial production without requiring the highest-tier setup. Coal can be processed into coke, then ground into coke powder, creating a practical chain for sustained use.
For a growing factory, build the fuel producer with enough output to cover its own heating cost first. The surplus is the amount that actually powers your other machines. This avoids the common mistake of calculating a fuel line’s gross output while ignoring the fuel burned to refine it.
When a line must run continuously, give it a visible buffer. A storage box before the furnace input helps reveal whether production is gaining, stable, or slowly falling behind. If the buffer drains during normal work, the problem is supply rate, not merely storage capacity.
Choosing and Upgrading Fuel
Refinement generally improves fuel density, but do not assume the newest fuel is mandatory. Low-heat stations, intermittent recipes, and mixed areas containing non-heated devices can run well on lower-tier fuel. Reserve dense items for places where belt capacity or machine count creates a real constraint.
| Situation | Sensible fuel choice | Reason |
|---|---|---|
| First heated crafting lines | Planks or charcoal | Easy to produce and distribute |
| Wood-based fuel expansion | Charcoal Powder | Better belt density than charcoal |
| Mid-game continuous production | Coal, coke, or Coke Powder | Strong heat value with manageable chains |
| High-throughput factory aisle | Black Powder or Blast Potion | Reduces belt pressure |
| Large late-game floor network | Blast Potion or Panacea Potion | Very high heat per item |
Fuel Efficiency upgrades increase fuel heat value, effectively reducing how many items are needed for the same workload. Factory Efficiency also matters because it affects device production and heat-consuming speed. A change to either upgrade can alter the balance between a fuel producer and its consumers.
Treat upgrades as a reason to re-check a working design, not as a substitute for one. A line that barely works may still stall if its fuel belt has no margin. Conversely, an upgrade may free enough capacity to redirect an existing fuel source to another department.
Avoid these common problems:
- Feeding every furnace from one early, low-density belt.
- Expanding consumers before checking heat demand.
- Burning raw materials that would create more useful refined fuel.
- Ignoring the heat used by the fuel-production chain itself.
- Assuming a larger heating device makes consumers craft faster.
- Building one enormous shared network before proving its throughput.
FAQ
What is alchemy factory fuel used for?
Alchemy factory fuel is burned in heating devices to provide heat for furnaces, blast furnaces, and the heat-consuming machines they support. Without it, heated production stops.
Does better fuel make machines faster?
No. Fuel type changes how much heat each item provides, not the processing speed of the consumer. Better fuel mainly reduces delivery pressure and refueling frequency.
Why do multiple crucibles on one furnace save fuel?
The furnace has a fixed heat cost of its own. Multiple crucibles still each require heat, but they share that one furnace cost instead of requiring separate furnaces.
Is centralized fuel distribution always best?
No. Central belts are convenient, but dedicated fuel loops are often more stable for high-priority production areas. Choose based on throughput, layout, and how much risk you can tolerate from a shared shortage.
When should I switch to coke powder or potions?
Switch when your current fuel belt cannot reliably supply demand, when space is limited, or when a large machine group needs dense fuel. Lower-tier fuel remains suitable for modest or intermittent heat loads.