We have recently increase production at our brewery and are concerned about air quality for employees. Is there a calculation for how much CO2 is produced per barrel of beer fermenting? We are trying to figure out how much air will need to be replaced in the building. Is there a sanitary way to vent CO2 from fermenter to outside?

The Safety Exchange Says: We are glad to hear that your brewery is taking the hazard of CO2 in the brewery seriously and even more excited to hear that you are considering the use of ventilation controls.

Our back of the envelope calculations indicate that a 10-bbl batch of average strength beer produces about 48 kg (848 cubic feet) of CO2. This is easily enough CO2 to cause a workplace hazard if you don’t have good ventilation. Exposure will depend on your specific brewery set up, your cellaring practices, production schedule, and space configuration.

Fermentation is not the only CO2 source in a brewery. Other exposures your employees might encounter can include dressing down the tank in preparation for CIP or working in a cooler where there is a CO2 leak.

To get a better idea of the contaminant generation rate and employee exposure, it is best to conduct area and personal air monitoring before you make a design or financial commitment to a solution. You will want to conduct similar monitoring upon installation of your system to verify the efficacy of control. Installation of CO2 and O2 alarms may also be a good idea.

In choosing general or local exhaust ventilation you will need to consider the configuration of the space, the capital cost of the system, and the operating expenses over time. If your concern is to minimize CO2 exposure following tank emptying, it is a good idea to run a hose from a blowoff arm to the outdoors and vent the CO2 directly to the outdoors. Be sure to open the CO2 valve slowly to avoid a flailing hose.