Blowout!

I brewed ales and meads with a group of friends for about two years, starting twenty years ago. I stopped after a while; friends moved away, and it just didn't fit into my schedule for a while. I'm pretty happy to be starting back up.

This weekend I brewed two fermented beverages: a mead (technically metheglin: fermented honey, ginger, and cinnamon), and a porter ale. The latter is a dark ale with moderate bitterness, and was the source of some trouble. I was up until 4am nursing a cranky batch of beer, and my bathroom is currently (pleasantly) scented with the aroma of hops and barley.

The porter I brewed, like most ales, is made of water, sugars and starches from malted barley, and hops (for flavoring and preservation). This concoction is called the wort. When the wort is cool, yeast is added; the yeast will convert most (sometimes all) of the sugars into alcohol. The hops release their oils during the boiling process; these oils impart flavor to the finished beer. The yeast, as part of its fermentation process, generates carbon dioxide as a byproduct.

This fermentation process usually takes place in a carboy:
. At the top of the carboy in the picture, you can see what's called an air-lock; this allows the carbon dioxide to escape, and prevents oxygen (and anything else) from coming into the carboy. When things are going well, the air-lock will make a bubbling sound, often about once per second (sometimes more frequently, especially at the beginning, and sometimes less frequently, as the sugars are converted). If the carbon dioxide cannot be released, the air-lock may be expelled rather forcefully from the carboy. While the wort is fermenting, heavy particles sediment out to the bottom (the trub), and lighter particles and oils rise to the top (kraeuzen).

It was the kraeuzen, the bitter oils and particles, that clogged up my air-lock on the porter. I returned home from an evening out, to find the air-lock across the room, and kraeuzen all over the carboy. I attached a blow-off tube to the air-lock's stopper, and allowed the kraeuzen to continue to bubble out overnight; when I finally heard it start bubbling steadily (around 4am), I was able to re-sanitize the air-lock, and attach it back to the carboy.

Because there was steady fermentation the whole time, I'm pretty sure there was positive pressure heading out of the carboy at all times; I'm pretty sure no contaminants entered during the process. Nevertheless, I'm going to keep my eye on it pretty closely over the next few days.

If you have any questions about brewing or any recipes, please ask!