Direct answer

With the recipes verified so far, the best early Cauldron use is Plank → Oblivion Essence if you have a plank surplus, followed by Vitality Essence → Oblivion Essence for the pair of essences, because both build toward the late-game essence loop. Wood/plank production inside the Cauldron is a fun side path, not the main goal.

How to judge “best”

CriterionQuestion it answers
Input availabilityCan you feed it steadily with what you already produce?
Output valueDoes the output sell, feed research, or unlock chain content?
Achievement valueDoes it progress a rare achievement?

Ranking of verified formulas

1 · Plank → Oblivion Essence

PlankOblivion Essence
Best when planks are mass-produced (“The Plank Baron” grind). Feeds the spirit loop + “Tenacity” (1.7%).

2 · Vitality Essence → Oblivion Essence

Vitality EssenceOblivion Essence
Pair with #1 to cover both essence achievements; progress toward the end-game chain.

3 · Inputs → Plank

Plank
“Overqualified” (2.2%) — proves the Cauldron makes planks; useful if your plank line bottlenecks.

4 · Inputs → Wood

Wood
“Wood by Cauldron” (2.2%) — a spare wood source before the World Tree.

What to wait for

Community-claimed recipes (sulfur combos, “advanced cauldron” outcomes, fertilizer interactions) are unverified for 1.0. Until the formula table carries a badge, treat them as leads — the data standards page explains why we hold values back rather than guess.

The rule of thumb

Brew what you can feed steadily and what feeds the loop you are building. The Cauldron shines as a converter for surplus, not as a primary producer — except for the “make a plank with a cauldron” achievement, which is purely decorative.

Evidence boundary

Formula existence: OFFICIAL. Output values/rates: PENDING. Ranking is editorial, built on verified facts only.

Independent fan reference for Alchemy Factory. Game data refers to the current official 1.0 build (Steam, PC). Field-level evidence is flagged on each page with OFFICIAL / OBSERVED / COMMUNITY badges; amounts shown without a badge come from the official 1.0 patch notes or store descriptions.