Mold Grows In My Fermentation Chamber - Home Brew Forums
Home Brew Forums > Home Brewing Beer > Fermentation & Yeast > Mold Grows In My Fermentation Chamber
Cool Brewing Corny 5G & Mini Giveaway

Thread Tools
Old 07-05-2010, 06:50 PM   #1
Join Date: Oct 2008
Location: Bella Vista, AR
Posts: 41

I use an old chest freezer as a fermentation chamber.
I ferment at approximately 67 degrees.

After three weeks a large amount of mold and other "stuff0" starts to grow in my fermentation chamber.

It is a pain in the @$$ to clean up.

Is this normal?
What can I do to prevent it?
Will it impact my beer?


Yellow Dog Brewing Company
"Follow The Dog"

Reply With Quote
Old 07-05-2010, 07:26 PM   #2
Join Date: Jan 2008
Location: Minneapolis, MN
Posts: 90
Liked 5 Times on 4 Posts
Likes Given: 2

Chest freezers do not make good fermentation chambers, they are only marginally better for serving beer. The problem is they are not built to handle moisture the way a refrigerator is. Mold is a common problem, there is no way to keep it from happening. Some use Damprid but the best option is to get a refrigerator and use that.

Reply With Quote
Old 07-05-2010, 07:45 PM   #3
Petey's Avatar
Join Date: Oct 2006
Location: Lawton, OK
Posts: 141

I've had the same issue in my fermentation fridge...try a tub or box of Baking soda. It doesn't stop it dead in its tracks for me but it takes a hell of alot longer for it to develop now.
Primary# 1: Dry Irish Stout
Primary# 2: Munich Helles

Secondary# 1:
Secondary # 2:

On Tap:
Robust Porter
White IPA
Dry Irish Stout

Kegged & Waiting:

Reply With Quote
Old 07-05-2010, 07:47 PM   #4
Join Date: Dec 2009
Location: Central PA
Posts: 197
Liked 2 Times on 1 Posts
Likes Given: 1

I use mine as a fermentation chamber/lagering chamber. I have quite a few 'shop towels' that I line the bottom of the freezer w/. I change these out after every cycle of fermentation.

The other thing I do is take up all of the dead space w/ 1 gallon water jugs. This helps regulate the temperature better by acting as a sort of insulation thereby lessening the amount of time the freezer has to run.

Like goswell says, it is tough to avoid but by doing what I've outlined above I have not had a problem w/ mold, just quite a bit of moisture. One more thing, try to limit the amount of time that the freezer is open; this allows moisture to condense inside.

Reply With Quote
Old 07-05-2010, 08:35 PM   #5
Join Date: Jul 2010
Location: Florence, OR
Posts: 791
Liked 14 Times on 13 Posts
Likes Given: 29

Originally Posted by Bert1097 View Post
Itake up all of the dead space w/ 1 gallon water jugs.
Keep a large thermal mass in the frige (as mentioned above), keep it dry. I hose my chest freezer down with Starsan every other week and wipe it dry.

Good Luck!

Reply With Quote
Old 10-05-2012, 04:26 PM   #6
Join Date: Oct 2012
Posts: 20
Likes Given: 1

I Just set up a small fridge with the A419 controller and would like to avoid this problem.

What do you all think about using a few large silica gel packs; the kind used when you get items shipped to you?

Reply With Quote
Old 10-05-2012, 04:31 PM   #7
Join Date: Sep 2011
Location: Robbinsdale, MN
Posts: 796
Liked 73 Times on 60 Posts
Likes Given: 12

+1 to damprid. Had condensation pooling and sometimes mold in a fermentation chest freezer. Cleaned it up with starsan and put a bucket of damprid in and have't seen any condensation pooling since.

Reply With Quote
Old 10-05-2012, 04:48 PM   #8
Senior Member
Hammy71's Avatar
Join Date: Sep 2008
Location: , Maryland, The Tax Me State
Posts: 5,861
Liked 518 Times on 393 Posts
Likes Given: 806

When you don't need it to work as a fermentation chamber (after the first week of fermentation or when not in use), leave it open. Stagnant moist air is your worst enemy. I use a fridge for my chamber, when it doesn't have a carboy in it, I have it cracked open a good six inches. Mold be gone....

Reply With Quote
Old 10-05-2012, 05:00 PM   #9
Join Date: Nov 2011
Posts: 3,952
Liked 552 Times on 388 Posts
Likes Given: 418

Problem solved:

Eva-dry E-500 Renewable Wireless Mini Dehumidifer

autonomist3k Likes This 
Reply With Quote
Old 10-05-2012, 05:31 PM   #10
Join Date: Jul 2012
Location: Austin, TX
Posts: 122
Liked 6 Times on 6 Posts
Likes Given: 6

Non-clumping crystalline cat litter is a cheap source for the exact same silica crystal used in commercial desiccants. Make a bundle with a single layer of cheese cloth and toss it in to the bottom of your chest freezer.

Every few weeks, spray the inside of the freezer down with Starsan and you should be good to go. You can also help yourself by cleaning any wort drips off of the outside of your fermenter.

Reason: Corrected type of desiccant.

Reply With Quote

Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
Mold and condensation in fermentation freezer aekdbbop Equipment/Sanitation 12 05-12-2010 05:15 PM
Slow Fermentation / Mold? alden Fermentation & Yeast 9 10-09-2009 03:58 PM
Mold or Fermentation? libertyman Beginners Beer Brewing Forum 3 04-10-2008 09:17 AM
American Craft Beer Grows Again! DeRoux's Broux Commercial Brew Discussion 6 03-02-2006 03:19 AM

Forum Jump