[t-bone]

OK Guys this one has me scratching my head.

I use a 26 cu foot chest freezer with a Johnson controller for my fermentation chamber.  A while back I was making a few batches of various lagers (four in total) and had them fermenting in the chest freezer.  I got lazy for a couple of these beers and didn't make yeast starters.  As a result the beer, all the beer, got horribly infected, lactobacter most likely.  OK flash forward a few months and I placed another couple of beers in the freezer and they also got infected.

I suspected a sanitation issue.  I tore down all my equipment and scrubbed, pbw'd, and star sanned everything.  I use a blichmann thermonator  plate chiller and I pumped pbw at 150 deg thru it for about four hours.  Then cooked it at 350 deg in the oven and pumped pbw back thru it.  Then I soaked it in star san for an hour.

I made another couple of batches  and didn't place them in the freezer.  No issues.  Then I made a run of the mill ESB, a recipe I have brewed dozens of times with no issues and placed the beer in the freezer and viola infection.  The ESB was pitched with dry yeast that was rehydrated exactly as specified by the directions.

Here's the question can a freezer harbor a lactobacter infection and if so how do you get ride of it?

Thanks

pat

[morticaixavier]

I'm sure it could. I would wipe the whole inside of the freezer down with dilute bleach OR vinegar solution.

The odd thing is that lacto doesn't really like it cold. It should take quite a long time to be noticeable at cold (60s) temps.

[kylekohlmorgen]

Most chest freezers controlled at fermentation temps sweat quite a bit. Mine will mold if I'm not careful.

I would add some Damp Rid containers after scrubbing and thoroughly drying out the freezer.

I think you've got a bigger problem in however the infection is working its way into your fermentors.

Are you using a blow off tube or airlock? Are you making sure the airlock stays full of vodka/sanitizer? Do you take frequent samples in the freezer?

Do you use different fermentors/airlocks/lids/etc. when you ferment in the freezer? I know if I put a bucket with airlock in my freezer on the shelf, it wont fit.

[t-bone]

I use standard air locks filled with everclear.  I definitely get a moisture built up in the freezer.  I installed a couple of 120 mm computer fans to circulate the air and put some silica gel crystals. 

Could the lacto have found its way into a part of the freezer that's not easily accessible.  Such as the inner walls or coils of the unit?

thanks for the help

[AmandaK]

Quick question: did you taste/smell this infection?

"Lactobacter" is not anything I'm familiar with - perhaps you meant lactobacillus or acetobacter? The first one will produce a clean sourness, sometimes with a white geometric film on the skin of the fermenting beer. The latter will basically produce vinegar.

So if you did, what did you taste?

Have you unplugged, defrosted and completely cleaner your freezer? That seems like a logical place to go from here.

[kylekohlmorgen]

I ferment in a 100-year old basement. Mildew, spiders, and dog hair galore.

Point is - the location of your fermentor is relatively unimportant. The beer should be protected by the fermentor, unless you're constantly opening the lid/stopper OR your fermentor has a leak (bucket/lid seal, carboy stopper, empty airlock).

The most probable is that you're letting bugs in when you sample in the freezer OR your airlock is empty.

The liquid inside the airlock can be sucked inside the fermentor during fermentation, if you burp the lid of a bucket, or if you move the fermentor. Make sure your airlocks are full before and after fermentation and periodically during lagering.

Don't open the lid/stopper all the time! If must sample IN the fridge, wipe down the surrounding area and lid, spray with Star-San, quickly sample and cap, then wipe the Star-San off. Or just pull out the fermentor when sampling.

[AmandaK]

The most probable is that you're letting bugs in when you sample in the freezer OR your airlock is empty.

This is my bet as well. Seems like all other points of infection have been covered by the OP.

[t-bone]

The taste is definitely acetobacter.

I will keep an eye on the fluid level in the airlocks.  I do not sample in the freezer.  On the last beer, the esb, I didn’t even pull a sample at all.  Filled the airlock with everclear and left it alone for two weeks and kegged.

I haven’t defrosted the freezer since its set at 65 degree and has no frost build up on it.

Thanks for the suggestions

[cornershot]

What kind of fermentor? Glass? Plastic? SS? Wood? Stone? An old, hollow gourd?

[t-bone]

Well the gourds  were on back order so I have to settle for glass carboys.

[klickitat jim]

This thread jinxed me. Actually it was my own laziness. I spilled a very small amount when I placed my fermentor in the freezer two weeks ago. This morning I discovered it had molded and my beer seemed to have a hot fusel sour smell to it. Looked fine but dumped to be on safe side. I unplugged freezer and sprayed down with bleach water. Left lid open to air dry.

Lesson 1 don't be lazy with spills
Lesson 2 wipe down with bleach water every batch.

I'm also going to try a Dry Z Air to keep the humidity down.

[cornershot]

Well the gourds  were on back order so I have to settle for glass carboys.

Could your airlocks or bungs be harboring acetobacter?

[bwparilla]

Just a thought, maybe the freezer cooled the ferment too quickly and what you think is lacto is a bad case of aceteldehyde.

[denny]

Just a thought, maybe the freezer cooled the ferment too quickly and what you think is lacto is a bad case of aceteldehyde.

Boy, those are pretty different flavors.

[t-bone]

The beer had a very sour rancid flavor that overwhelms all other flavors.  The beer was also cloudy with a fine white haze.  My uninfected beer tends to be very clear.  Also this flavor increases with time so after about a week and a half the beer is so bad it is impossible to drink more than a couple of sips.

Since I don't have a microscope I am guessing this is acetobacter.  Am I incorrect in this guess?

I thought of the bung thung also so I threw them out and ordered new ones.