Airlocks...Unlocked

Please permit me to rant about something just this once. ::smug grin:: I might apologize in advance for preaching homebrewing heresy, but I won't. It's my blog, and if you don't like it you don't have to read it (but who doesn't like their ego stroked?; I don't have any followers yet anyway.). However, it is my hope to dispel the myth of the necessity of the airlock, though I may have to pry it from the cold, dead hands of some stalwart homebrewing brothers and sisters. Nevertheless, as purveyors of the fermentive arts, we are often quite concerned (some of us more anal-retentively than others) with cleanliness and sanitization. Don't get me wrong! Such practices are without question the most important skills homebrewers can employ to ensure a quality (if drinkable) product, but we sometimes do things that have overly negative consequences solely because we think we have to, someone told us he had to, or because we just don't know any better. There is ALWAYS choice, both in brewing and in life. There is also ALWAYS consequence. (You didn't pay for that. It's just a little extra bonus existential wisdom from me to you.)

Enter, the myth of the necessity of a closed fermentation vessel. Closely related to sanitization practices, the use of an airlock is one of the more popular ways to create a (physical) barrier that allows the escape of CO2 and prevents the ingress of O2. Airlocks also (in theory) prevent unwanted baddies/dust/bugs/etc. from getting in the fermenting beer and causing potential contamination/infection. But are they really necessary? That depends, but I'm leaning toward "no." Before you write me off as a lunatic and stop reading, first consider the products of fermentation. A fermenting food or beverage produces three things:  alcohol (everyone's favorite); Carbon dioxide; and, heat (rarely mentioned because of its obvious ubiquity). In addition to contamination, the other anathema of brewers is oxidization. (Let's not kid ourselves. For all brewers, more for homebrewers than professionals, some oxidization is inevitable. There is some transfer of oxygen when racking to secondary, and during bottling, unless one purges with CO2 and is extremely careful.) During fermentation, kreuzen and CO2 form a barrier of physical substance as well as positive pressure above the beer, thus preventing ingress of O2 and making an airlock unnecessary. If fermenting in a bucket, a loose fitting lid or, in a carboy, a sanitized piece of foil to cover, is all that is necessary. Some even leave that space open on purpose, but that's another topic (sort of). The reasoning behind this is that if some undesirable substance was to get in the beer, it would have to travel up, against the force of gravity (not to mention against the positive pressure of escaping CO2) to enter the beer. This is highly unlikely, as most floating particulate falls through the atmosphere via gravity.

Okay, so you've got airlock(s). Why not use them? I'm not preaching against airlocks, per se, but against the strict use of airlocks to the exclusion of all other reasonable methods of achieving the same purpose. However, there are other reasons you might not want to be restricted to an airlock. First, if you're a homebrewer, having some version of the following is not a matter of if, but when. These experiences usually occur for the less experienced homebrewer, or for the homebrewer who is dogmatically opposed to change/enjoys cleaning beer off his/her ceiling:

Or this:

I think these videos prove most of my points. Sure, in the second video, the guy could have used a blow-off. But the use of a restrictive device like a blow-off tube (just like a jet engine) will create more force and (according to Newton's 2nd law of motion) potentially push more of your beer out of your fermentor and into the blow-off receptacle. Again, a loose fitting lid or piece of foil works just fine. Recently, I was chatting with a homebrewing friend who shares a brewing space with other homebrewers. He recounted to myself how he had to clean up some of his equipment in the aftermath of an airlock explosion when other brewers borrowed his brewpot in an attempt to contain potential blow-off. First of all, this is unacceptable, but it is also just plain dumb. My friend said the other brewers were attempting a FFF Darklord clone (also kinda dumb) and had allowed coffee and cacao nibs to enter the primary fermentor, thus clogging the airlock and causing a huge, albeit greatly aromatic, mess. Again, unacceptable. I fail to see the point of putting coffee and cacao nibs in primary in the first place, but to, then, tempt fate with an airlock? Mind-boggling! But I digress...at least use a blow-off, but again, a loose-fitting lid or piece of foil is sufficient.

Another reason (though, admittedly, less important for the homebrewer) one might not want to use an airlock is the potential effects of osmotic pressure on yeast. Research suggests that fermenter geometry and pressure can stress yeast such that growth rates and fermentation characteristics are negatively affected. An open fermentation (loose fitting lid; foil cover) alleviates this pressure and (in my experience) tends to accentuate fruity esters, especially in hop-forward beers.

Finally, there are several commercial breweries that use open fermentation (some for centuries), including Ommegang, Sierra Nevada, New Glarus, Jolly Pumpkin, Anchor Brewing, D. L. Geary, and Samuel Smith's. If the best in the business ain't skeered of open fermentation, neither need you be. Just be careful and follow a few basic rules with open fermentations:
-Practice good sanitization methods
-Until active fermentation has commenced: cover, but loosely is fine
-It's even okay to uncover and let your beer breathe during active fermentation (kreuzen)
-Temperature control. Always a plus.
-Size of fermentation vessel may dictate, but leave enough head space to allow for kreuzen (this may mean  brewing smaller recipes, heaven forbid.)
-When fermentation slows down, positive pressure decreases. Insert airlock now.
-Be smart with your hose (in all things, but especially when racking to secondary so as to reduce O2 (transfer)!

Finally, if you doubt what I'm saying (and that's okay; doubt is an essential element of enlightenment), here is at least one article by some titans of craft beer who are also proponents of open fermentation. Enjoy! Be Fermentive!

Living by example (Altbier)