Airlock Blowout

In the commercial world of brewing, one of the biggest fears is a fermentation that is slow to start or one that lacks vigor when it does come to life. These traits foreshadow problems lurking on the horizon. Any microbiological critters coming forward into the fermenter from wort production or bacteria associated with pitching yeast are much more likely to take hold in a fermenting batch of beer if fermentation does not take off quickly and with command of the situation. Alcohol production, pH reduction and oxygen consumption all occur in the early stages of fermentation and collectively help to build a hurdle for bacterial takeover. The combination of inhibitory factors is indeed known as the hurdle theory by those who study food microbiology. The more hurdles put before unwanted organisms reduces their ability to colonize the environment. In the world of beer, decreased pH, alcohol, reduced oxygen and the competitive nature of a healthy yeast population make it rough on unwanted guests, like spoilage bacteria and yeast. The opposite of this is true when funky, sour beers are being produced. Too many hurdles, especially hop bitterness, reduces the chances of being successful with these funky brews.

So blowing off your airlock is not a bad thing because it is an indicator of a healthy fermentation. But blowing your airlock is really not the best thing for your beer, your carboy or your home. Airlocks help protect your beer from the environment outside of the fermenter. When it launches from the top of the carboy you are no longer protected. Airlocks can become clogged and fail to launch like a missile from the carboy and this can cause carboys to break. When an airlock launches from the carboy foam may follow and when a carboy breaks beer is sure to follow. Both of these things are bad for the home. The take home message is that blowing off your air-lock should be avoided if at all possible.

Another problem associated with blowing off “stuff” during fermentation is loss, since beer is a major component of this “stuff.” Commercial brewers typically have 25-35% headspace volume in fermentation vessels to minimize or completely eliminate blow off during fermentation. The take-home message is to consider using a 6-gallon (23-L) carboy for your 4- to 5-gallon (15- to 19-L) batches.

The best thing to attach to your primary fermenter is a blow-off hose that allows for a large volume of carbon dioxide and foam to escape the fermenter while preventing the formation of pressure that can cause the problems described above. All commercial breweries, ranging in size from the smallest to the largest, use some sort of device to allow gas and liquid to flow out of the fermentation vessel because this sort of problem can grow from a small-scale nuisance to a large-scale disaster.

The good news to report is the health of your fermentation seems to be excellent! I think future batches will be improved by the use of a blow-off tube better able to handle the active nature of your fermentation.

Response by Ashton Lewis.