In a quality control lab, the lab tech counts the yeast and determines how much of it is needed, the optimal time to harvest and pitch it, and monitors its health. PCR tests check for contamination. Does the beer have off flavors, is it ready for package, and does it fit the brand profile?
“Quality control is so important. Every brewery should have a quality control department,” said Judy Elhamalawy, who developed the Quality Control program at Five Boroughs Brewing Co., a microbrewery in Brooklyn, NY.
“Under pitching leads to stress in the yeast. It has a harder time reabsorbing diacetyl, which increases tank residency time, which messes up the production schedule,” Elhamalawy said. “It could lead to yeast mutations and competing infections because the alcohol doesn’t get produced fast enough.”
“Over pitching leads to the yeast mutating to ‘lazier versions,’ which reduces efficiency and can mess up the production schedule,” she said, “Stressed yeast can lead to hydrogen sulfide, or rotten egg smell.”
After fermentation, the lab ensures that, on the micro level, the beer is up to the parameters for each brand. It is carbonated, clean, and good to leave the brewery. Once the beers are out in the world, according to Elhamalawy, “the worst thing bars can do to beers is not clean their lines.”
In addition to a lab, sensory panels are utilized to make sure the science is right and the quality is consistent, Quality Assurance. “We look at attributes for each brand, for example, our stout, and scale it within a range,” said Amanda Benson, Sensory Panel Coordinator at Deschutes Brewery in Bend, Oregon.