Questionable Fermentation Practices (archive)

Originally Posted 10/24/07

I didn't want to leave anybody hanging with no updates for days after an introduction that promises so much. I should have mentioned that I work Sunday through Wednesday, at least 10.5 hours a day. That means, after my first post today, I won't normally update again until Sunday afternoon. But, since this is my first day, I thought I'd start giving an idea of what exactly I do.

By title I am a "brewer." However, I work in the cold room. I do cellaring, not wort production. The wort producers brew the beer, put it in a fermenter, pitch the yeast, and turn it over to us. We in the cold room take care of the beer from that point until it is taken to be bottled or kegged. So, the primary daily production tasks of a cold room employee are racking beer from the fermenter to a conditioning tank, and then filtering that beer. When I was hired I was told I would start in the cold room and learn wort production after a few months. I should begin training in wort production soon, but no one has given my any indication that it will actually happen in the near future.


The typical life cycle of a beer for us is three days of active fermentation. Once the beer achieves the desired finishing gravity on the third day the beer is chilled down to around 40-50 degrees and about half of the yeast head is skimmed off the top of the open fermentation vessel. We are able to use open fermentation because we use only one rather famous strain of yeast for every beer we brew. On the 6th day the beer is racked out of the fermentation vessel, and on the 7th day it is filtered, carbonated, and possibly packaged.

If that sounds way too fast to you, you're not wrong. Personally, I think that many of the problems often attributed to our yeast are actually due to this extremely rushed process. Rushed fermentation and cold crashing a beer immediately upon attenuation causes the yeast to drop out before they're really done all their work, particularly reabsorbing diacetyl produced during fermentation. Let me just say that if you know what diacetyl is, you probably know exactly what I'm talking about here, particularly with regards to our yeast and our brewery. Fuethermore, we actually put recirculation pumps in the beers to make them ferment even faster. Our yeast is particularly flocculent, so we use pumps to suck beer from the middle of the fermenter and spray it back on top, depositing some of that yeast that is dropping out back on top of the yeast head. How we don't have horrible problems with picking up airborne infections and serious oxidation is beyond me. I suppose we manage to avoid infection by having a brewery so dominated by our one yeast that nothing else has a chance to take hold. Regardless, this just seems to be a terrible and unnecessary idea, unless your priority is to crank as much mediocre beer out of the brewery as fast as you can with little regards to quality. I won't be all that surprised if someone tells me that this is actually a common practice, but it is just so counter to everything I've ever been told about good fermentation practices.

Also, temperature control is a huge issue. Our brewmaster does not trust technology. He has an extreme aversion to it, to quite a fault. Temperature control is a perfect example. We have no automated temperature control on our fermentation vessels. All we have are a few pipes that run around the perimeter of the vessel, carrying coolant through the beer much like a wort chiller. Each vessel has a set of valves, one in and one out, that we must open by hand to cool down the beer. The cold room is kept around 60 degrees, but the thermal energy produced by fermentation causes the beer to heat up significantly if it is not constantly monitored. On a given day there are anywhere from 3-6 employees working in the cold room, but on the days I work I am solely responsible for fermentations. Part of this job is to pull a sample from each actively fermenting beer and check the temperature every few hours. Most of our beers must be fermented between 66-72 degrees. I have gotten quite good at maintaining and controlling the temperatures. However, as some strange relic of the company's past, I am required to "put the fermos to bed" every day before I go home. What this means is that I am to cool the beers down to 66 or 67 degrees before going home so that they won’t overheat before midnight, when they will be checked again. This used to be done because there was no one at the brewery overnight to check on the beers. These days we have someone there 24 hours, so there is no need for this practice, yet this is how it continues to be done. Sounds like an OK idea until you learn that some fermentations are so active that they can go from a perfect 66 to 74+ degrees in a twelve hour period. Also, consider that on a daily basis it becomes extremely easy to leave the coolant flowing through a beer for too long cooling the beer down far too much. When this happens, our method of damage control is running hot liquid through those same pipes, heating the beer back up. No, this is not good for the beer. I personally feel that lack of proper temperature control is a huge factor in the lack of consistency of our product. At times I have tasted differences in the flavor profiles of beers that were overheated or overcooled. All this could be averted if we simply put some thermostats on the fermenters, not to mention the labor saved, but our brewmaster refuses to do so.

Overall, this is the first major frustration of my job. We live in the dark ages. We brew beer with an intentional lack of technology. This not only makes our lives as employees more difficult, but more error prone and therefore more likely to be detrimental to the beer. Yet, we insist on filtering the beer. ..