One of the papers I’ve been relying on heavily here at the Brew Basement is called “Aging characteristics of different beer types”, which was accepted into the Journal of Food Chemistry on July 17th 2006. It’s an absolute treasure trove of info for a cellaring enthusiast. Today I’d thought I’d share with you a few off the cool graphs that were published in this article, as they illustrate some of the ideas I’ve been sharing with you in some of my past Beer Cellar Science postings.

This study examined eight different Belgian beers that were aged at 20 degrees Celsius (68 degrees Fahrenheit) over the course of a year. At various points and times, samples were taken from these brews and analyzed for their chemical content. Three pilsner beers (labeled L-A, L-B, and L-C in the charts below), and 5 specialty Ales (labeled S-A through S-E below) were studied. Beers S-A and S-C were dark beers, while beers S-B through S-E were all fairly high in ABV%.

The first chart notes the concentration of Fury Ethel Ether (or FEE for short) that was found in the various beers over time. As you might remember from my previous article, FEE is responsible for solvent-like flavors in aging beer.  

As you can see from the diagram, all of the beers tested showed an increase in FEE concentration. However, the most dramatic jumps came from beers that were high in alcohol and/or dark in color. This neatly agrees with the theory that FEE is formed through reactions involving ethanol and/or various malliard components formed during the brewing process.

This next diagram tracks the rising levels of diacetyl in these beers.

In my article on Diacetyl, I talked about how Diacetyl was thought to be formed in aging beers through the Maillard Reaction, which is a type of reaction that occurs between a protein and an acid. Beers that are darker and higher in ABV% naturally contain higher concentrations of the maillard precursores as a result of their brewing process. Just as we would expect, this graph shows these beers as having the larger increases in Diacetyl concentration.

Changes in Ethyl Lactate concentrations, thought to be responsible for banana-like flavors in aging beer, are shown in the next diagram.

Once again, we can see the higher-alcoholic ales experiencing the greatest changes in concentration. In this case, the changes can be directly traced to a reaction that occurs between ethanol and the organic acids naturally present in beer.

Finally, the last chart examines the change in color of the samples.

Here we can clearly see pretty much all of the beers becoming darker over time. This is primarily due once again to our old friend the Maillard reaction.

There are a bunch more diagrams like this in the paper, be sure to check them out if you’re interested.

The main thing that I took from this study was just how incredibly complicated a process that aging beer can be. Different styles of beer, along with differences in brewing process, can result in dramatically different aging behaviors.  Even beers that are stylistically similar can have very different flavor profiles after aging.

I think that this is what has me in love with this hobby. There’s so much unknown here, so much new ground to tread on. Every beer I store down in the cellar is just full of possibilities, dammit!

Thanks for reading!

Jason

jason@brewbasement.com