Infection? - Overpowering Chemical Scent

Short version:

I've got a batch of Oatmeal Stout in fermenters that is putting out an extremely strong antiseptic/chemical/sour-ish odor. The closest thing I can find to same smell is lemon Chlorox wipes, but the fermentation smell is MUCH stronger. I foolishly removed the blow-off bung and took a good whiff. It felt like somebody physically stabbed me in the nose.

I've never encountered that smell before, let alone in that strength.



Background:

6-8 weeks ago I brewed the same beer, and had the same problem. I let it finish primary before tasting a sample. It was thin, powdery/astringent, mildly sour, with no hint of any expected roasted flavors. I pitched it and started looking for a culprit.

I settled in on my plate chiller and blamed inadequate cleaning.

I spent a few hours doing an over-the-top cleaning of the chiller Wednesday. I ran 190 degree PBW through it and got a ton of gunk. I mixed up a fresh batch and ran it again, this time in both directions for about half an hour in each direction. I then flushed with water and ran 140 degree StarSan through it in each direction.

Prior to this batch, I hooked it up during the boil and ran it, without cooling water, for the last 20 min of the boil and for an add'l 15 minutes of whirlpool before starting to fill fermenters.



If this is the same infection as the previous attempt, I'm struggling to identify and eliminate the culprit. My technique isn't lab grade, but I'm pretty thorough, and in 10+ years of brewing have never experienced a major infection...

Ideas?

 

Non-food grade plastic somewhere after the boil?

 

The physical-nose-stabbing sounds like CO2 bite. A good, close whiff of actively-fermenting beer, or even just beer that's out-gassing as you transfer it to secondary, will be emitting enough carbon dioxide to physically hurt; it's your body's way of saying "hey, I can't breathe this, buddy, better back the *%&! off if you want to live to procreate the species."

Otherwise... antispetic/chemical sounds more like contamination, possibly from chlorine/chloramines if you've recently changed something with your water supply? But "a ton of gunk" in the chiller also sounds pretty sketchy, are you sure there wasn't more gunk to be gotten out?

 

Alas, no...

Stainless Camlocks, silicone hoses, March 809 pump, and Better Bottle primaries.

Camlock, hoses, and fermenters are three batches old.

 

I hope to God you're right about the CO2 scent. I might have to crack a valve on my keg CO2 bottle for comparison sake. I'm gonna be pretty upset about scrapping 15, and maybe 30, gallons of beer. (I brewed again today).

On the water supply side, I haven't changed anything. I'm using a single stage R/O to remove chlorine. I'm planning better down the road, but that's it ATM.

Am I certain there wasn't more to be gotten? No. That's the problem with a plate chiller; there's no way to see inside...

In addition to the two way hot PBW purge and two way StarSan, I baked it this time at 225 for an hour before the pale I brewed today. If the stout is bad but the pale is good, I'll have my culprit...

 

Fermenting too hot? A similar thing happened to me before I had good fermentation temp control. Smelled like a really strong chemical cleaner.

 

Nope. I'm fermenting in a chest freezer dialed in for 65 F

The freezer also had some mold in it after the 1st batch I did. I've cleaned that pretty aggressively, but I know mold is notoriously hard to get rid of. Still, I'm running closed fermenters with either blowoff tubes or airlocks and the smell I'm talking about is 24 hours after pitching...


BTW: I love the trouble shooting. Even if they're dead ends, it rules things in/out.

 

Where is the temperature probe? Different temperatures between the air, up against the carboy, and in the middle of the wort.