Brewing Secrets from Boundary Bay

Anthony, one of our brewers here at Boundary Bay Brewery, has been badgered lately to explain to those of us less versed in the chemistry of beer (meaning me…one of the Graphic Designers here!) why and how Boundary Bay Brewery uses co2 in our brewing process.  This is his response:

the fermenting tank

the fermenting tank

the bright tank

the bright tank

“I don’t want to geek out too much but there are a few basic things to know about co2 and beer.  First of all, yeast produces co2 and ethanol (or alcohol) during the fermentation process.  Once there is alcohol in the beer you don’t want it coming into contact with any oxygen.  Oxidizing ethanol changes it into acetic acid or vinegar.  Just like that old adage about turning wine into vinegar, beer will do the same thing.  During the fermentation process yeast is producing abundant co2.  When the fermentation is nearing completion we’ll “cap” or close off the fermentor tank, allowing pressure to build and carbonation (which is just dissolved co2) to naturally form in the beer.  After two days of this, we’ll chill the beer in the fermentor causing the yeast to go dormant and settle out.  This naturally clarifies the beer which is important since we don’t filter any of our beer which can strip flavor!  A day or two later we’ll transfer the beer from the fermentor to a bright tank that will allow the beer to further clarify naturally.  If the beer is a little light in carbonation at this point, we can add a little with a co2 stone.  Before we put beer into a bright tank we first sanitize it and then purge all of the air out with co2 to avoid oxidization (which, remember, causes acetic acid or vinegar!).  When we move the beer from tank to tank, we don’t use a pump, but force it out with co2 pressure, much the same as forcing beer from a keg.  Speaking of kegs, all of our kegs and bottles have to be purged with co2 before filling.  We transfer the beer from the bright tank into one of our serving tanks or fill kegs.  The serving tanks hold 16 barrels (or 32 ‘full’ kegs) of beer and run straight to the bar where we have 10 styles on tap all of the time.  Sometimes, we’ll fill kegs straight from the fermentor and then let them finish fermenting in the keg.  This is known as cask conditioning and we serve a different cask every Thursday night.  Cask beer is usually carbonated lighter and has a softer mouthfeel since all the co2 in the cask comes from the yeast.”

** if you have questions you’d like one of our brewers here at Boundary Bay to try answering for you, contact us and we’ll get Anthony or Aaron or Steve to answer your brewing questions! **

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