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The Witcher 3: Wild Hunt

How to Find the Hidden Laboratory at Corvo Bianco

Nathan Garvin

Here’s some information about the hidden laboratory in Corvo Bianco, including how to unlock the hidden laboratory, how to dismantle mutagens, how to restore your potions and bombs and increase the number of potions and bombs you can carry at a time.

Corvo Blano’s Hidden Laboratory Walkthrough

During the Main Quest The Beast of Toussaint you’ll be given the deed to Corvo Bianco, and later (likely after the Main Quest Blood Run you’ll have a prime opportunity to return there and learn about the estate and how to upgrade it, all of which is covered in the Side Quest No Place Like Home.

After returning to the vineyard, talking to the Majordomo and getting a tour of the estate you’ll be able to talk to the Majordomo about upgrades. The upgrades - all of which must be purchased to earn the achievement/trophy Playing House and complete the quest No Place Like Home - are quite costly, and buying them all will set you back 14,000 Crowns. Fortunately there’s no need for you to spend quite that much money to unlock the hidden laboratory, although the upgrade you do need to buy is still quite expensive.

(1 of 2) Upgrade the manor house and your attention will be directed to a weak wall in the cellar.

Upgrade the manor house and your attention will be directed to a weak wall in the cellar. (left), Beyond the wall you’ll find an abandoned alchemy table where you can transform monster mutagens into more generic mutagens. (right)

Talk to the Majordomo and pick the dialog options “Think we could do some renovating?” and “Let’s do some work on the house.” and he’ll suggest a general refurbishment to the house, which will set you back a painful 5,000 Crowns. Ouch. Pay it, wait three days, then talk to the Majordomo, who will mention that the workers found something in the cellar while working and suggests that you check it out. Do so now and you’ll find a weak section of wall you can blast with Aard, beyond which is a high-quality and intact laboratory fit for a master alchemist… and more than capable of supporting a naughty Witcher who intends to dabble in mutagens.

Sure enough, search a nearby table to find Julius ban Gavh’e’s Letter which details his great discovery - a method for turning monster mutagens into other, more common mutagens. Use the alchemy lab and you’ll bring up a menu by which you can see the various monster mutagens you’ve collected on the left, and what you can turn them into on the right. This is a free process, and serves the purpose of allowing you to make use of those long-since obsolete mutagens to fund your newfound need of Greater Mutagens. For example, one Wraith Mutagen can now be converted into a Lesser Green Mutagen. That’s not all this place has to offer, either, as you can interact with a small table to the north to replenish your expended alchemical tools (potions, bombs and decoctions) and also to increase your maximum stock of potions and bombs, free of charge.

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Guide Information
  • Publisher
    CD Projekt
  • Platforms,
    PC, PS4, Switch, XB One
  • Genre
  • Guide Release
    24 June 2015
  • Last Updated
    18 July 2024
    Version History
  • Guide Author
    Nathan Garvin (Haeravon)

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You are Geralt of Rivia, a professional monster-hunter known as a Witcher. You’ve fully regained your memories since your miraculous revival and escape from the Wild Hunt, and have cleared your name of the false accusations of regicide. In the wake of the assassination of Foltest, king of Temeria, the north have been rent by warfare as Nilfgaard launches its third major invasion, and the northlands have been united under the insane king Radovid. Overshadowing these petty politics is the mysterious return of Ciri - Geralt’s adopted daughter, who is now being pursued by the Wild Hunt.

The guide offers the following:

  • A full walkthrough that’s more than just a listing of quests-it’s an “ideal chronological order” that will get you through the whole game and allow you to see and do everything the game has to offer.

  • Side quests, including monster contracts and treasure hunts for obtaining powerful Witcher sets.

  • Descriptions of decisions, quests, and events that influence the various endings of the game.

  • Crafting and Alchemy information.

  • General strategies on how to take down foes large and small, monstrous and humanoid, boss or mundane.

  • Information on how to complete all the Gwent quests and obtain all the Gwent cards, including detailed Gwent strategies.

  • Trophy/Achievement information.

MASSIVE UPDATE: 7th September 2016 ongoing

  • Added DLC quests “Fool’s Gold” and “Scavenger Hunt: Wolf School Gear”.
  • Organisational changes in the Velen section of the walkthrough to reflect the increased level of Griffin School Gear.
  • Organisational changes throughout the walkthrough to provide a “no skulls” path through the game.
  • Added Death March difficulty tips and commentary throughout the guide.
  • More XP reward numbers included.
  • Walkthrough now includes additional information based on patch changes.
  • Various typo and grammar fixes.
  • Added DLC pages for Blood & Wine, Heart of Stone
  • Lots more quality of life improvements

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