What's that smell?!

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menschmaschine

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I have an all-grain lager fermenting at 48 F in my chest freezer. It's actively bubbling away and is about at high krausen or maybe just a little passed. I used WLP830 (German Lager) yeast. It has that great sulfur aroma, but if I really get my head down in the chest freezer (without losing consciousness) there's an acrid (but somehow pleasant) odor that burns my nose! Anyone know what that is? It's almost estery, but I was surprised at how it burned my nose and took my breath away.
 
menschmaschine said:
I have an all-grain lager fermenting at 48 F in my chest freezer. It's actively bubbling away and is about at high krausen or maybe just a little passed. I used WLP830 (German Lager) yeast. It has that great sulfur aroma, but if I really get my head down in the chest freezer (without losing consciousness) there's an acrid (but somehow pleasant) odor that burns my nose! Anyone know what that is? It's almost estery, but I was surprised at how it burned my nose and took my breath away.
That there is CO2.

Pop a cold 7-Up. Pour it into a glass without ice and take a whiff. It'll give you the same suffocating burn.
 
menschmaschine said:
I have an all-grain lager fermenting at 48 F in my chest freezer. It's actively bubbling away and is about at high krausen or maybe just a little passed. I used WLP830 (German Lager) yeast. It has that great sulfur aroma, but if I really get my head down in the chest freezer (without losing consciousness) there's an acrid (but somehow pleasant) odor that burns my nose! Anyone know what that is? It's almost estery, but I was surprised at how it burned my nose and took my breath away.

Sounds like CO2 build up and the smell of your beer fermenting. Your chest freezer doesn't allow much of the co2 to escape and since its heavier then oxygen it contains almost pure co2 and will burn if inhaled.
 
We have a big 7'x3'x3' incubator at work, kept at 5% CO2, when you open that thing you get a big nose full of it. Yeah, takes you breath away, literally.
 
Thanks for the responses everyone. I just thought it had to be more than CO2. CO2 is an odorless gas so why would it burn my nose?
 
boo boo said:
I think that yeast is the same as WY2308. And if it is, then a diacetyl rest will be in order before you rack to secondary.

Yes, that's part of my regimen. Even if it could do without, I try to do it anyway... just to have the yeast clean it up and ensure fermentation is really complete before lagering.
 
CO2 is an acid gas, which is why it burns your nose. It is also not quite odorless, but has an acrid sorta smell. Don't overdo it, don't want you pitching headfirst into the freezer and knocking over the fermenters.
 
AiredAle said:
CO2 is an acid gas, which is why it burns your nose. It is also not quite odorless, but has an acrid sorta smell. Don't overdo it, don't want you pitching headfirst into the freezer and knocking over the fermenters.

You're right in stating that CO2 is an acid gas (it's better to consider it an acidic gas, but technically by itself it is an acid gas), but it is also a tasteless, odorless, colorless gas. Ever smell dry ice? I have and it didn't burn my nose. There is some other fermentation by-product giving it that bite and I was just curious if anyone knew.
 
boo boo said:
Yeah, me too. I do a rest anyway. Don't hurt.

I've been brewing for about a year. I've done four all grain recipes and three turned out very nicely but I tried a Kolsch that failed miserably. I noticed that smell when I recked it to my secondary and the finished product has a very pungent odor. What is the rest for and do you think it would have saved the batch?
 
Top Shelf Bob said:
I noticed that smell when I recked it to my secondary and the finished product has a very pungent odor. What is the rest for and do you think it would have saved the batch?

The rest is a diacetyl rest normally associated with lagers since diacetyl is not desired. In lagers, a couple days at a higher temperature at the end of primary fermentation, allows the yeast to "clean up" the diacetyl in the beer. Check out this article for diacytel rests and low-temp ale fermentation: <http://byo.com/mrwizard/871.html>. Hopefully that answers your question.
 
menschmaschine said:
Thanks for the responses everyone. I just thought it had to be more than CO2. CO2 is an odorless gas so why would it burn my nose?
It turns into carbonic acid in your nose. It's a similar chemical reaction to the one that makes you cry when you cut up onions.
 
thebikingengineer said:
It turns into carbonic acid in your nose. It's a similar chemical reaction to the one that makes you cry when you cut up onions.

THANK you! That sounds reasonable and like you know what you're talking about. :)
 
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