Week 6 at UC-Davis
If think back to my childhood and try to recall what made me most excited to wake up in the morning and get to class as soon as possible, there is really only one thing that comes to mind. Field trips. Sometimes the destination wasn’t even all that important. Just getting on a bus and being away from the constraints of the classroom was enough to make it all seem like a mini vacation. As you may have already guessed, we had a field trip of our own this week. The difference for me 20 years later is that the destination was of the utmost importance. For myself it was a homecoming of sorts, but for the rest of our class it may as well have been trip to one of the seven wonders of the world. We were on a bus headed for Chico, CA. Our destination was the Sierra Nevada brewery.
Upon our arrival, we were split into groups and given an extended tour of the entire facility by various members of the brewing staff. It was nice to have people that most of us would like to emulate take time out of their busy day and provide us with information that Joe Blow celebrating his 21st birthday with all his buddies don’t have the privilege of getting. There were a few things that stood out to me as we made our way through the their facility. I don’t recall seeing one kernel of grain, puddle of liquid, or any other brewing material on the ground at any time. I wasn’t expecting it to be a mess mind you, but a brewery of this size being absolutely spotless I found to be very impressive. Also, the fact that they do not pasteurize their beer was no shocker to me, but that some of their beers aren’t sterile filtered either was. To me that is a testament to their whole cleaning/sanitizing regimen that they must employ throughout the brewery. Having the ability to produce beer in this manner and not have any significant issues involving beer spoiling microorganisms is truly amazing. They of course have a lab staff looking at every brew for those little buggers as a safety precaution.
Towards the end of our tour, the gentleman conducting it stopped to show us some sort of custom vehicle that resembled a cross between a bicycle, an RV and a pub that they had made for promotional purposes. Apparently the fact that it is essentially a beer bar on wheels has caused some legal hurdles and it has been curbed (literally) for the time being. More proof that “the man” is going to eventually make having fun a misdemeanor. After the tour, they informed us that we had tables waiting for us and that the beer was on the house. Needless to say, we made sure to sample nearly all of the styles they had to offer. My favorite was a milk stout that despite being only 3.7% ABV, still packed in a great deal of flavor. I think that will be going on my list of future brews I want to make at home.
The remainder of the week was devoted to the biochemistry of fermentation and flavor compounds. This was one of those times when I said to myself, “thank god I just took organic chemistry last fall." For all you folks that are thinking about doing this someday, here are some of the topics you may want to study up on ahead of time: The glycolytic pathway of yeast, transamination, the roles of Magnesium & Zinc during fermentation, the relationship of acetyl CoA and ester production, the origins and formation of higher alcohols, the role of oxygen in the wort... just to name a few. I think a lot of us were surprised to hear that the uptake of oxygen by the yeast cells at the beginning of fermentation is in and of itself completely incorrect. The uptake of oxygen occurs prior to fermentation, which is anaerobic. I was also enlightened by the fact that the yeast is not reproducing during this time, but uses the oxygen to produce unsaturated fatty acids and sterols. A yeast cell uses them to bulk up it’s plasma membrane so that when the oxygen is depleted, it can make it through the biathlon of reproduction and fermentation that we as brewers demand.
On Tap for Next Week: Flavor Stability