Crafting Recipe
Fill the outer ring (8 slots) of the 3x3 crafting grid with cobblestone, center empty = 1 furnace. Cheapest furnace material — just 8 cobblestone from a wooden pickaxe.
Efficient Usage Tips
Fuel values: Lava bucket (100 items) > Coal block (80) > Blaze rod (12) > Coal/Charcoal (8) > Planks (1.5). Coal for daily use, coal blocks for batch (+20% efficiency), lava for AFK. Automate: hopper on top (items in), hopper side (fuel), hopper below (output).
Upgrades: Blast Furnace & Smoker
Blast Furnace (5 iron+3 smooth stone+1 furnace): smelts ores 2x faster (ores only). Smoker (4 logs+1 furnace): cooks food 2x faster (food only). Place both next to furnace for complete workstation.
What It Smelts
A furnace handles three categories: ores (iron ore to ingots, gold ore to ingots, sand to glass, clay to bricks), food (raw meat to cooked, doubling restoration and removing poisoning risk), and misc items (wet sponge to dry, cactus to green dye). One coal smelts 8 items — your early-game efficiency unit.
Fuel & Upgrades
Fuel priority: lava bucket (100 items, best) > coal block (80) > coal/charcoal (8) > planks (1.5). Once you reach the iron age, upgrade immediately: a blast furnace smelts ores twice as fast with more XP, and a smoker cooks food twice as fast. Both are worth building.