View Full Version : CO2 in one area dangerous?

08-12-2007, 04:29 PM
Okay, so I have three batches going in my spare room closet. Two are actively fermenting, the other is done or finishing, so the smell is potent and rich. Will the CO2 produced from fermentation become harmful, if too many batches are going at the same time? I know CO2 won't kill you, unless it is in great amounts to prevent you from breathing Oxygen, however, get this... When I statred my very first batch, the next day my Hedgehog (who lives in the room not the closet where the mead was) started to get sick. I thought, ok he isn't eating very much, and he is getting old, so it might be his time... My wife was thinking, wow you just killed Hedgie with your mead!

Anyhow, he is dead now, but in my opinion not due to the mead. But, what if? Now my daughter is in the next room... Should I be worried?


08-12-2007, 04:49 PM
I seriously doubt three home brew size fermenters could alter your home atmosphere enough to harm the occupants. Unles you are in the habit of making your home or room perfectly air tight. Then you would need to worry more about your own Co2 production (exhaling). Put a couple plants in the room, it might make them happy and will increase local oxygen levels.

Sorry about Hedgie....but it was his time to go. Not your fermenters

08-12-2007, 08:44 PM
Hey, thanks for the reply. Thats a good idea to put plants in the room, I should try that! Yeah, I think it is a little silly to think my three batches would be enough to harm inhabitants, it was just weird that the death of my hedgehog happened the couple of days after I started my first batch (first time home brew-er)


08-13-2007, 11:32 AM
I'm an engineer, and when I saw this I thought, "This is something that we could calculate to find out if it's safe or not." So here goes.

Let's say you started three 5-gallon batches all at the same time.
Let's say that the starting gravity of each batch was 1.130.
Let's say that you have a strong, healthy ferment, and that the three batches of mead ferment to dryness (specific gravity of 1.000) over the course of 5 days.

Fifteen gallons of mead (or any liquid) at a specific gravity of 1.130 weighs 135.6 pounds. After the mead ferments to dryness (to SG of 1.000) the fifteen gallons weigh 120 pounds. If we subtract the final weight from the starting weight we find that 15.6 pounds of CO2 was released into your room. That means that your mead is throwing off about 3.12 pounds of CO2 per day.

According to Wikipedia (http://en.wikipedia.org/wiki/Carbon_dioxide), the average person produces around 2 pounds of carbon dioxide each day just by breathing. Therefore, if you would feel safe having two people in the room with your hamster, you should feel pretty safe with three batches of mead in the room. I wouldn't recommend shutting yourself in the closet with the mead, but of couse I wouldn't recommend shutting yourself in the closet with two people either. ;)

Just for the heck of it, I figured out what the CO2 concentration would be in a 10 x 12 x 8 foot room if the room was sealed airtight so the CO2 couldn't get out. I used the ideal gas law (PV=nRT (http://www.shodor.org/unchem/advanced/gas/index.html)) and found that the same three batches of mead would produce 136 cubic feet of CO2. The room is 960 cubic feet, so that means that the room would be at around 14% CO2. That would definitely kill your hamster (normal air is 0.038% CO2). But the average room in a house is nowhere near airtight, otherwise we'd all suffocate in our sleep when we closed our bedroom door at night.

08-13-2007, 02:56 PM

Science and math are wonderful, aren't they?


08-13-2007, 03:26 PM
:) i better not tell this to my GF, otherwise ill find my two cats in the cabinet with the mead :P