Since my last post to this site I embarked on a strict diet of reduced carbohydrates ( read….reduced beer intake…). Only a temporary measure I keep telling myself….

I recently bought some low alcohol beer at the grocery store made by German brewing company Becks. I was disappointed when I cracked open a bottle. The skunky, foxy aroma was overwhelming. I was further disappointed when a family member told me that Becks low alcohol beer always has that aroma – that’s why he never drinks it.

My thoughts immediately hearkened back to the brewing course I took in Semester 1 at Heriot Watt University taught by Dr. Dawn Maskell. I learned that the skunky aroma in beer is an aroma-active compound called 3-methyl-2-buten-1-thiol. Called MBT for short, it has an aroma threshold of 0.2–0.4 nanograms/L in water and 4–35 nanograms/L in beer. MBT was detected as early as 1875 by a scientist called Lintner who described it as having meaty, sulfury, and skunky-foxy notes. Modern day science has now determined that when a brewer adds hops to the wort boil, the alpha acid in the hops changes structure slightly (isomerizes). The isomerized molecule present in beer stored in clear or green bottles that get exposed to UV light of wavelength 350 to 500 nanometers will shed a chunk of its molecular structure called an isoprenyl leg. This isoprenyl leg portion of the alpha acid molecule is the MBT.
Science has also revealed that during fermentation yeast can assimilate amino acids. Ssulfur-containing amino acids, cysteine and methionine also have been implicated in the formation of skunky flavor. There are a number of ways of creating low alcohol beer. I am not entirely sure how Becks does it, but somehow in the fermentation process, cysteine and methionine have not completely been taken up by the yeast. And the use of green bottles then only adds to the problem.

I long for the day when I can resume my beer consumption. In the interim, I see no grounds for continuing a relation with Becks Low Alcohol Beer.