Our "Glass Dolls" pilsner was inspired by a brewery in Italy that uses floor-malted Czech pilsner malt in a lower abv beer.  The intent was to increase mouthfeel and body so that beer didn't end up too dry on the palate.  For those of you unfamiliar, "floor malting" is an ancient practice of germinating the barley spread across a floor and turning it by hand.  This barley, made and malted in Czech Republic, has a lack of uniformity by design and therefore some characteristics that we really like, although hard to quantify.

Glass Dolls tasted wonderful during fermentation, extended lagering, filtration and even in packaging.  We were super proud of it.  Then this little flavor and aroma problem popped up about a week ago: diacetyl or it's twin 2,3 pentanedione.  It's the flavor of buttered popcorn and is produced from normal yeast fermentation.  We go through many steps in brewing to mitigate or eliminate its presence in our product.  Simply put: Wayfinder doesn't do diacetyl.  I was thinking it was only a hint of diacetyl and that maybe we could live with it.  I'm more sensitive to it than most people and I thought maybe it was just me.  But the problem just got worse. 

Here are my thoughts on why it happened:  diacetyl is formed during glycolysis when the yeast expel a-acetolactate and then turned into diacetyl through oxidation or heat.  Here's a handy link showing that pathway.   The diacetyl can remain in the beer or be reabsorbed by the yeast.  In most healthy fermenations the diacetyl is reabsorbed.  The problem arises when either two things occur: later fermentation caused by outside sources (dry hopping, adding fermentables, or infection of non-yeast microorganisms) or an excessive amount of a-acetolactate that never truly converts to diacetyl to be reabsorbed by yeast.  I believe it's the latter.  Although a theory of mine, I believe that our fermentation produced excessive amounts of a-acetolactate from lack of free amino nitrogen in the floor malted barley.  I also believe that this is why Czech beers tend to have the same problem.  They taste fresh with no diacetyl at the brewery, but then diacetyl becomes more apparent the older it gets. 

Our quality checks in the brewery are vigorous because we are so small and can't afford a lab staff, let alone a machine to measure diacetyl through gas chromatography.  We end up using time (which is really expensive!) and our own palates to make sure these problems don't arise. 

I know that small amounts of diacetyl are acceptable in some styles of beer: Czech lagers and Cask Ales to name a few.  However, my saying has always been "although the presence of diacetyl is appropriate in some styles, its absence is appropriate in all styles".  Expect no distracting diacetyl in Wayfinder beers in the future.  Our aim is to make beers that are moreish, clean, delicious and still a little brash now and then.