Blog – Quality Control

Hey y’all! We’re back with another behind the scenes look at the goings-ons at PEI Brew Co. This time we have Spencer Gallant, one of our brewers and QC masters. Let’s take a look…

Quality control is a vital piece of the puzzle when it comes to beer and continues to gain importance as the industry grows. Every brewer wants their best work to be poured from the taps or purchased from the shelves. Running certain QC procedures can help assure that their best work is reaching the consumer. At PEIBC our lab is small, but allows us to conduct vital tests/measurements and continues to grow. I will describe what I consider the most important tests a brewery can carry out to obtain great quality beer.


1) CO2: being able to carbonate beer to the level that corresponds to its style is important to add to the thirst quenching experience. It also helps for packaging; too high of a CO2 level can make it disastrous to pour a pint and too low of CO2 will leave you with no foam to get caught in your moustache. We use a Zahm & Nagel CO2 tester which takes a pressure reading of the beer in the Bright Beer Tank or Serving Tank (where filtered beer goes to be carbonated and packaged) and matches it with the temperature of the beer. From there, we use those two numbers to find the level of CO2!


2) Dissolved Oxygen (DO): Oxygen is on the list of beer’s worst nemesis. Oxygen can cause beer to oxidize which yields a paper/cardboard flavour over time, especially if beer is kept warm. So, always store your beer cool! After fermentation, beer can pick up oxygen during filtration, transferring, and packaging, therefore it is important to check for oxygen pick-up in the beer before it hits the market. We use a DO meter where beer is pressed through a membrane which measures the level of oxygen and gives a digital reading in ppb (parts per billion). This can be measured right from the tank, or out of a bottle/can. If the DO is too high, there are different procedures that can be carried out to lower the DO and get the beer in spec.

3) Microbiology: Handling yeast is one of the most difficult tasks in the brewery. Sanitary procedures are very important to not contaminate your yeast with wild yeast or bacteria. Wild yeast (any type of yeast other than the desired yeast strain used by the brewer) can be found everywhere; wood, a brewer’s beard, or even dust particles! These unwanted organisms can throw unwanted flavours into your precious beer and are a real hassle to be rid of if a contamination occurs. After each yeast pitch into a brew, we plate a sample of the beer in various media that promote growth of certain yeasts/bacteria. Therefore if there are any of the unwanted organisms in our beer we will know after a few days by looking at the plated samples. If the beer is clean, the plates will not show any colonies of growth and we carry on laughing and brewing. An example of a bacteria you may find in your beer is lactobacillus. This is an anaerobic bacteria that produces lactic acid which will make the beer sour. If it were to grow in the media after being plated, it would appear as long skinny rods under a microscope. 


These are only a few of the simple QC procedures we conduct at PEIBC but are all very important to help us produce great beer. As our lab grows we hope to add more and more QC procedures to master the beer game. Beer is filled with science – a very enjoyable and delicious science.

– Spencer