“Statistics are like bikinis. What they reveal is suggestive, but what they conceal is vital.”   - Charles Bamforth

I’m not sure if he borrowed that from someone, or if he just pulled that out of the sky, but Charlie certainly knows how to get a point across. That was his way of conveying to the class that we needed to look beyond the numbers themselves when it comes to brewing statistics and interprete the meaning behind them.  Any professional brewer can tell you that 1000 parts per million of oxygen in a bottle of beer is way too much.  You also need to know the impact this number has on the finished product to fully grasp the possible causes and solutions that will help bring it to acceptable levels.  So why is too much oxygen a problem?  I’ve got two words for you, flavor stability.  

I’m sure that at one point or another in our lives, we have all opened a beer that was either made at home or commercially that didn’t taste quite right.  I’m not talking about a beer that has gone sour due to contamination or that has simply gone flat.  What we focused on primarily this week was flavor stability (also referred to as beer staling) and what factors contribute to it.  The most common flavor and aroma associated with this is that of wet cardboard.  Here are some of the major culprits that are involved:

Oxygen - Being the highly reactive molecule that it is, oxygen is always on the prowl for other ions and compounds to hook up with.  Higher levels in the beer post fermentation increase the chances of it completing it’s mission and causing you to wonder why it smells like a package the UPS guy left in the rain.

Metal Ions -  Iron and Copper love to get oxidized.  Just imagine what rust and blue-green copper can do for your beers flavor.  Not very tasty.  The various metals used in pipes and brewing vessels, along with your water supply can be a source of them.

Carbonyl Compounds - Too many of these, such as E-2 Nonenal will only contribute to stale flavors.  Sulfites can be added to the beer to reduce the carbonyl groups and diminish the negative impact they have on the beer. This solution is not being used in the U.S. due to it’s negative connotation and the government’s requirement to print “contains sulfites” on the label.

Temperature - This is by far the most important factor.  For every 10 degrees Celsius an environment is raised, the oxidation reactions will occur 2-3 times faster.  So if your beer is in your garage instead of your refrigerator and it’s late spring/early summer in west Texas, go get it out now!

Time - Is not on our side in this instance.  Just like a high school teenager, the  aforementioned compounds and reactions will only have a better chance of getting your beer into trouble the longer you let them hang out.

The Beer Itself - As with any other flaws that a beer can have, the less intense the flavor of a beer, the more obvious it will be that something has gone awry.  If Light Lager X has the same level of staling that Bob’s Barleywine has, it will be much more easily detected in the lager, because there are less flavor compounds to mask it.

We also went over good housekeeping and cleaning processes with Dr. Lewis this week.  I found the most intriguing part to be one of the methods used for testing the effectiveness of your brewhouse cleaning procedures.  You can use a swab to take a sample from the surface you want to test and then place it in a small amount of a compound named Luciferin.  It was discovered in the body of firefly’s and is responsible for their ability to light up, which they use to attract a mate. Luciferin is useful to brewers because it reacts with the ATP in microbes and organic residue.  The sample is then placed in an instrument which gives a Relative Light Unit (RLU) reading as a result of it’s bioluminesence.  The more light it gives off, the less clean the surface is. 

In addition, Dr. Lewis made a very clever observation about how the lives of young adults could have benefited greatly if god or evolution had equipped humans similarly to the firefly. Picture yourself at your favorite local hangout and you're currently unattached.  Can you imagine how much easier life would be if all you had to do was have your ass light up to signify that you’re available/looking?  We'll have to add that to the "nice to have" list for scientists working on DNA research.  Until then, it looks like we’ll have to settle for small talk and liquid courage.

On Tap for Next Week: A trip to Fairfield & various forms of beer packaging.

Questions or Comments?  Feel free to email me at beereaucrat@gmail.com