Brewing Safety - CO2

I didnt see a safety forum going so if this is misplaced please let me know.

I just read in my 8th graders homework that CO2 is odorless. Having had a face full of the gas as I bend over into my chest freezer where I ferment I can tell you that the stuff is down right offensive. It burns my nostrils like snorting cocacola.So I did a litle reading about it online here

http://www.last-word.com/content_handling/show_tree/tree_id/3713.html

and some other web pages but it seems like there is a lot of conflicting information and not a lot of agreement. Does any one have an expert opinion? I'm concerned because sometimes I have 8 5 gallon fermenters at full on fermentation at the same time in the basement. could the gass be harmful to me or my pets?

Thanks.

What you are reacting to is not so much the presence of CO2 so much as the absence of oxygen. 8 carboys is a lot of beer, but the volume of CO2 produced is actually not so crazy. Figure a batch of beer puts out about 400 L of CO2, which is a bit more than a person will put out in the course of an average day. If your basement is getting enough air circulation that 8 people or so won't suffocate over the course of an evening, you're fine.

I've had more than twice that much beer fermenting in my back of the garage brewery without taking special steps to ventilate and that's safe because there is a fair amount of air circulation through that room at all times (i.e. even with doors closed there are leaks, where the plenum comes in etc.). If your basement does not receive any air circulation then I suppose you are right to be concerned.

As you have noted a snootfull of CO2 is quite painful but that isn't enough to protect you. If you go blissfully charging into a room that is full of CO2 exhaling while on the way in and inhale for the first time while you are well within the room I understand that O2 will pass into the CO2 so fast that you will pass out before you can get back to the door (this happens with other gasses too).

I think the best thing for you to do is look up the MSDS for CO2 and then get a CO2 detector and measure the level in your space. I'm guessing it will be well below the level of concern but if there is any chance of a problem you should reassure yourself on this point.

As you have noted a snootfull of CO2 is quite painful but that isn't enough to protect you. If you go blissfully charging into a room that is full of CO2 exhaling while on the way in and inhale for the first time while you are well within the room I understand that O2 will pass into the CO2 so fast that you will pass out before you can get back to the door (this happens with other gasses too).

Click to expand...

Yeah, this might be even worse with CO2. In normal respiring tissue the production of CO2 causes the blood pH to drop which lowers the affinity hemoglobin has for O2 which causes it to dump O2 into the blood. Normally this is good since it causes O2 to be released near the tissues that need O2 but in a room full of CO2 it will just accelerate O2 leaving the blood.

Anyway, if you calculate the maximum amount of CO2 that a batch of beer could possibly produce (assuming all the sugar was converted to H20 and CO2) it might be enough to become worrisome if your basement has absolutely no circulation. Most likely the air circulation is orders of magnitude more than enough to deal with this. In terms of raw CO2 production, a gas furnace or stove probably pumps out as much CO2 in a minute or two as an entire batch of beer will produce.

It's funny this question - how much beer do I have to ferment to asphyxiate in a closed room - gets asked every few years. If you search around, someone actually did the calculation (its quite safe).

BTW the "sting" from inhaling CO2 is a noxious affect as it converts to acid as it hits your mucous membranes rather than an actual "odor"

Well clearly I need to take a chemestry class. Thank you all for putting my mind at ease. Case Closed.