Luna is providing critical service to Virginia’s craft beer industry

Brad Day, Associate Scientist
Biomedical Technologies

Microbiology may not be the first thing that comes to mind when someone mentions beer.  Nevertheless, the beer brewing process has evolved over centuries from an almost accidental craft to a science balancing microbiology with chemistry, art and a touch of luck.  Modern brewing incorporates many aspects, and key among them is the science of fermentation, or zymurgy as it is known.  Beer zymurgists are primarily concerned with fermentation as performed by the organism Saccharomyces Cerevisiae, commonly know as brewing yeast.  And while there are as many brewing yeast varieties as the brewers who use them, the overruling principle is simple:  yeast feed on carbohydrates extracted from malted grains and produce alcohol and carbon dioxide, two primary components of beer.  Without this simple single-celled organism beer as we know it simply would not exist. 

Beer brewing has experienced explosive growth lately with smaller craft breweries rapidly gaining popularity.  Production from these small brew houses varies from only a handful of kegs at a time to nationwide distribution.  Craft beer may not yet sell in the colossal volumes brewed by the likes of Budweiser, Miller and Coors, but both large and small breweries rely on their yeast population to produce their goods.

Brewing yeasts are not the only organisms familiar with fermentation, however.  Bacteria also fulfill minor roles in producing certain types of beer, notably many sour beers, such as Berliner Weisse or Flanders Red Ales, known for their tart punch.  Bacteria also turn carbohydrates into alcohol and carbon dioxide, but not always in the manner the brewer intends.  Unwanted contaminating bacteria can turn an otherwise good beer into a foaming mess or undrinkable swill.

Lactobacillus contamination. The yellow halo around the colonies indicates the bacteria are producing acid.

The most common of these contaminating bacteria are Lactobacillus and Pediococcus.  These acid producing bacteria can hitch a ride on malted grain dust or fester in improperly cleaned brewing equipment manifesting in what brewers call “off flavors” or producing overly fermented beers that taste watery and tend to foam excessively.  Frustratingly, not all of these flavors can be detected when the beer is bottled but rather make themselves known after a few weeks or months of sitting on a shelf.  Off flavors, inconsistent products and questionable shelf life can ruin the profits and reputation of any brewery, especially a small craft brewery that relies on word of mouth, social media and internet buzz as much as or more than traditional forms of marketing.  As such, quality control of finished products is highly important to the flavor and long term stability of a quality brew. 

Pediococcus bacteria with Gram staining

Earlier this year, LUNA’s microbiologists began to offer quality control services to local Virginia craft breweries.  Virginia’s craft brewery industry is expanding rapidly and there are now over 60 craft breweries in the Old Dominion (source:  We currently offer beer spoiling bacteria detection services as well as wild yeast screening (for contamination from non-brewing yeast.)  Our screening tests can detect low level contaminations and assist brewers with shelf life and storage issues or verify the effectiveness of their sanitation or CIP (Clean-in-Place) procedures.  Currently we offer several assays such as HLP (Hsu’s Lactobacillus-Pediococcus), SDA (Schwarz Differential Agar), LWYM (Lin’s Wild Yeast Medium) and LCSM (Lin’s Copper Sulfate Medium) as well as microscopic examination, on-site consultation and custom assay services.

Contamination of Lactobacillus and wild yeast, 250x magnification

Although our initial brewer customer base is close to our Charlottesville office in and around the Brew Ridge Trail ( and surrounding areas, we look forward to expanding our service offerings and extending our reach into the rest of the state.  In the meantime, Oktoberfest is upon us, so Cheers! Prost! Slainte! Na zdavi! L’chaim! Salud!

Contact Mike Danilich ( or Brad Day ( for more information.

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