Don't worry I and many others have had this happen. If you do the bleach for an hour and then rinse well and then soak/scrub with PBW and rinse well and then some Starsan then your mashtun will be as nice as it was before the mold. It only happens when we get in a hurry and forget to clean it. It is the perfect breeding ground for mold. Always air it out with it open so it drys out. Store with the lid open a bit.
Fermentor 1: Bill's House Ale II, Fermentor 2: German Helles, Fermentor 3: Bill's Schworzbier (Black Bier)
Tap 1: Bill's House Ale II, Tap 2: German Hefewizen, Tap 3: Nut Brown Ale
Future Brews: Stone IPA Clone, Blonde Ale, Budvar Clone, Newcastle Clone
New toy: Blichmann 27 gallon fermentor
“If you find yourself in a hole, the first thing to do is stop digging”
“Good judgment comes from experience, and a lotta that comes from bad judgment”