Blue Prince Laboratory — Element Mixing & Formula Solutions

Updated May 25, 2026 · 9 min read · All 7 stable formulas

The Laboratory is one of the few rooms in Mt. Holly where you can permanently improve your save file. Drag three vials onto the burner, watch the reaction, and if it's stable you keep the perk forever — across every future run. If it's not stable, the flask shatters and a random non-key inventory item dissolves. There are seven safe formulas, two run-ending mixes to remember, and a small trick with the Pantry that lets you visit the Lab twice in two days for free.

The Burner Rules

The Laboratory burner has three sockets, a flame intensity knob, and a "ignite" lever. The interface is simpler than it looks:

1. Three vials only. Trying to add a fourth wipes the slot empty. There is no two-vial recipe.
2. Flame setting is cosmetic. High flame and low flame produce identical reactions — the visible smoke just changes color.
3. One mix per day. Once you ignite, the lab door locks until the day ends. Re-drafting the Lab on a future day resets this.
4. Failed mixes do not consume vials globally. The vials in your inventory remain. What you lose on an unstable mix is a separate inventory item.

The 7 Stable Formulas

1. Iron + Salt + Coal — Coin Press

The first formula most players unlock. Adds +1 Coin to your daily payout permanently. Cheap reagents, all three appear in the entrance-hall starter rack. Recommended first mix on any save.

2. Mercury + Ash + Iron — Lock-pick

Adds a single-use Lock-pick to your starting inventory every day. Picks one locked door without spending a Key. Stacks once: a second mix overwrites and gives you a permanent +1 Lock-pick draft chance, no extra effect.

3. Salt + Sulfur + Ash — Key Draft

Every time you draft a new room, there's a flat +15% chance a Key spawns in it. Quietly the strongest formula for long runs — the Key economy is what bottlenecks Day 5+.

4. Honey + Mercury + Coal — Pantry Multiplier

The Pantry now gives double Steps when re-entered. Only matters if you draft the Pantry — pair this formula with a save file that always opens with Pantry in the rack (true after Day 2 on most layouts).

5. Brimstone + Iron + Sulfur — Fire Wand

Permanent Fire Wand in your inventory. Burns through Wooden doors at the cost of 5 Steps. Useful for Forgotten Wing access, but expensive — most runs never break even.

6. Honey + Salt + Brimstone — Vault Hint

The Vault Code letters (D-O-O-R = 4558) are pre-revealed on first Vault entry of every future run. Skip this if you already know the code — it does nothing extra.

7. Ash + Coal + Mercury — Step Buff (current run)

The only non-permanent stable formula. Adds +5 Steps to your current day's pool. Useful if you're mid-run and short, otherwise skip.

The Two Mixes That Wreck a Run

• Brimstone + Mercury + anything. All three pairings with Brimstone + Mercury detonate. Mercury is too volatile with sulfur compounds. You lose a random non-key item — most often a Coin pouch.
• Honey + Iron + Coal. Looks safe (three common elements), but produces a "tarry sludge" that voids the daily payout. Your Day-N Coin/Key/Step income returns 0 for the rest of the day.

The Pantry Re-Visit Trick

Drafting a Pantry next to the Laboratory lets you visit the Lab on consecutive days at near-zero step cost. On Day N you mix Formula A. The Lab locks. You sleep. On Day N+1, the Lab is re-drafted (rarity refreshes), you walk three squares through the Pantry into the same Lab tile, and mix Formula B. Two permanent perks in two days.

This is the recommended path to grind out Formulas 1, 2, and 3 (Coin Press, Lock-pick, Key Draft) by Day 3.

What Each Formula Saves to the Save File

Permanent formulas (1, 2, 3, 4, 5, 6) write to your save file's "Lab unlocks" array. They persist:

• Through deaths
• Through Permadeath restarts (yes, Lab unlocks are not wiped by Permadeath)
• Through New Game+ — but require re-mixing to re-enable in that NG+ run

Formula 7 (Step Buff) is current-run only and disappears at midnight.

Laboratory FAQ

Related Guides