Disaster Avoided - Blowoff

What's up all you Hosers?

Paul checking in.

Many of you may be wondering why I named myself 'Brew Meister?', and not 'Brew Master'. Well, here at Brew(u)nion Street Brew, we believe in being humble. We also rely on our good friend Murphy and his wonderful laws. Everyone knows Murphy's standard law: anything that can go wrong will go wrong. It's important to learn that Murphy's laws are no joke, but in fact, they are special cases of the second law of thermodynamics.What most people don't know is that Murphy's law has multiple disciplines, one of them being Murphy's Scientific Laws.

Two of these scientific laws are:
If an experiment works, something has gone wrong.
If the experiment works, you must be using the wrong equipment.

Well, thank God! Last night we had our first disaster. Everything is saved, but this event exemplifies why I'm a "Meister?" and not a "Master"!

The other night, while I was in my bed trying to sleep (and while our brew was in the heat of primary fermentation), I heard a loud pop. I turned my head and saw that our airlock had shot off our glass carboy, hitting the ceiling, causing hop and malt residue to explode all over the walls and ceiling. As I sat there stunned, not knowing what to do, there was a slight pause after the explosion and suddenly foam and beer began erupting out of the carboy, similar to a paper mache volcano that we've all made as kids. As I jumped out of bed, I frantically looked for my air-born airlock so I could place it back on the carboy and prevent anymore liquid gold from being lost.

 

This event is not uncommon, especially to newb brewers and hosers, like myself. This is known as a Blow-Off Event (BOE).

So why did our airlock blow off?

When active or primary fermentation happens, a thick layer of foam forms on top of the beer - this is called kraeusen. Fermentation produces A TON of CO2 as a byproduct and this can cause the kraeusen to get pushed into the airlock. The airlock is a small piece, but is integral in the homebrewing process. The general purpose of an airlock is to keep air in the carboy during fermentation, but due to the imprecise nature of homebrewing and the requirement for the fermentation process to maintain a maximum pressure level, the airlock must also regulate the amount of pressure that is in the carboy at any given time. If this airlock gets clogged (like ours did), pressure builds up inside the carboy and then BOOM, doneski! 

To avoid this Blow-Off Event, another type of system can be used, called a blow-off tube (BOT), which does the same job as an airlock. You fit the tube over part of the airlock, or even to the carboy itself, and this much larger space allows more gases to escape and also prevents clogging. 

After some research I found that a few things can cause a blow-off event; the first being the yeast selection. Certain yeasts have a greater propensity to create a "big fluffy head" and some ferment much more vigorously and violently. Our yeast wasn’t supposed to be super active, but as with any yeast batch, there is no guarantee, as they all act differently. Other brewers recommend having at least 1-2 gallons of headspace in the fermentation vessel for the kraeusen to expand. If kraeusen gets into your airlock, odds are, it's going to get clogged, and a blow-off event will happen. A second potential factor in a blow-off event is heat. Yeast kicks into overdrive when it gets hot. Another factor is the starting gravity. Higher gravity beers have ferments that are more violent since they have more sugars for the yeast to consume. 

Our yeast was super active and had a rather violent fermentation. We left around a gallon of head-space, but that obviously wasn't enough (looking back, we probably should have had at 1.5 gallons worth of head-space). It seemed like the lack of head-space and our over active yeast caused our blow-off event. GOOD NEWS: Our beer isn't ruined, and it looks like we only lost a couple pints of beer. Woo Hoo!

We are getting pretty close to transferring our beer to a beer bucket and the bottling will probably happen within 3-4 days. That's all for now; check in later for more updates on steam beer, and in the not-to-distant-future we will begin brewing (and posting about) a thick, sticky, stout! 

Over and Out,

Hosers!