If you haven’t already, please feel free to check out Part 1 and Part 2 of this series before reading on.

I’ll be covering two of the possible reasons (listed in Part 1 of the series) that beers high in ethanol content tend to age well. Let’s start with the more in-depth topic first:

3. Reactions Involving Ethanol - Beneficial reactions involving ethanol occur more often in beers high in ABV%.

Behind water, ethanol is the most common substance found in beer. Thus it should be no surprise that reactions involving ethanol in beer are very well documented and understood by the scientific community. Reactions that ethanol has a role in include oxidative reactions, ester formation, and probably most importantly, ether formation.

When ethanol reacts with certain compounds, typically those formed from maillard reactions, various flavorful ether compounds can result. The most important of these ethers is called Furfuryl Ethyl Ether (or FEE for short), and can lead to green apple or solvent-like flavors in your beer. In large amounts, FEE can have a harsh flavor. In smaller amounts however, FEE can add an enjoyable complexity to your brew. Studies have shown that FEE concentration is directly proportional to the abv% of beer.

There are a whole list of other ether compounds formed with ethanol, but none approach the concentration levels seen of FEE in beer. Regardless, these other ethers are associated with sweet wine-like flavors in aged beers, and definitely can lend a contribution to an aged beers flavor profile.

Known for their big fruity flavor, esters are an important part of the flavor profile of beer. Unfortunately, most esters are highly volatile, and degrade fairly quickly when beer is aged. However, as beer ages ethanol can react with various organic acids (such as lactic acid) to create new, more stable esters. Esters formed by ethanol reactions can include - get ready for some long words here - ethyl lactate (banana flavor), ethyl 2(and 3)-methylbutyrate (winey flavors, apple, orange, banana), and ethyl cinnamate (fruity sweet flavors). While these new esters are usually (but not always) fairly low in concentration, their flavor impact is enhanced when you considered the combined effect they all have. It has been shown that higher abv% beers tend to have more ester formation than lighter, less abv% beers.

Finally, ethanol has a starring role in various oxidative reactions due to it’s ability to pick up highly reactive free radicals. The effects of increasing ethanol levels on this oxidative mechanism have not been well documented, however.

In any case, there can be little doubt that reactions involving ethanol have increasing impacts on the flavor profile of aging beers as the abv% rises. Unfortunately, the flavor changes experienced can occur both in positive and negative directions.

2. Alcohol “Masking” Effect - High levels of ethanol do a better job of hiding or “masking” stale flavors then less powerful beers. 

There isn’t a whole lot of information regarding this phenomena in the scientific literature, although I have seen it mentioned more then once in various papers. I think it is more a statement made in common sense then in scientific fact. We’ve all had a tasting experience in which one flavor in a dish we ate completely dominated the others, and beer should be no different in this regard.

I think the important thing to remember is that strong alcohol flavors (or any strong flavor for that matter) could easily overwhelm subtle stale ones, and I don’t think you need a scientific paper to tell you that.

Thanks for reading, more soon!

Jason

jason@brewbasement.com