Open Hearth ★★

Taken all the way down to base materials, one Open Hearth is 3 crafting steps deep and needs 4 intermediates — Spruce Lumber ×4, Darksteel Ingot ×2, Firewood ×1 and 1 other — which resolve to 6 distinct raw materials totalling 60 units, plus 30 crystals.

That bill outweighs 13,112 of the 13,602 recipes tracked here and 1,419 of the 1,552 Carpenter ones, and 337 recipes nest deeper.

Only 2 of those crystals go into the final step; the other 28 are burned by the intermediates, so the real crystal cost is 12 Fire Crystal, 12 Wind Crystal, 2 Fire Cluster and 4 other kinds.

The chain crosses two disciplines — Carpenter to Lv 50 and Blacksmith to Lv 50 — so no single class can finish it unaided.

5 of the 6 raw materials come out of the ground, and 3 of them are time-gated: Bamboo Stick (7:00), Darksteel Ore (1:00) and 1 other. The widest gap between consecutive opening times is 16 Eorzean hours, about 47 real-world minutes.

Of the intermediates, Darksteel Nugget has the widest use: 121 recipes call for it, spanning seven of the eight crafting classes.