How Windows Can Help Improve Beer Quality

  • April 19th, 2018
  • By Stephen Rich

From Day One (last August :) ) we have been implementing leading technology and best practices and a variety of innovations to help make better beer with less water, less energy, and less waste. We are excited about this challenge, and the opportunities we are given to find new ways to refine old processes - all while working to improve overall efficiency and flavour at the same time. But some the most exciting innovations can come in the way of a basic afterthought of even a production or process flaw.

During many of the beer making processes at Cowbell, brewers move beer from one vessel to another, or even recirculate it within that vessel. We always use sight glasses during these activities so we can visually confirm and inspect the process. This is typical for any professional brewery. But, windows make up the entire west wall of our brewery cellar, which creates beautiful views and glowing light in our brewery, but light is bad for beer.

You may have either experienced or heard someone talk about skunky beer. This phenomenon, more technically known as lightstruck is caused not just by light, but specifically Ultraviolet (UV) light when it comes in contact with beer. If beer is not protected by a can, or amber bottle, the UV light that makes its way to the beer causes a photo-oxidation of isomerized alpha acids (hop oils dissolved to create bitterness), turning them to create skunky characteristics in mere seconds.

So here we are, clear in our commitment to make world class beer – but in the basic process it may appear to our Guests that we are exposing our beer to UV light? Not the case! The windows installed at Cowbell are specialty LoE3 windows, designed to drastically reduce the greenhouse effect, and help our energy needs in all seasons. These windows are nearly twice as energy efficient as standard double glazed, argon-filled windows.

The UV transmission of our windows is only 5%, compared to a standard window with UV transmission of 58% (see Appendix 1.1) Our windows are dual purposed – they help us reduce our energy needs AND keep harmful UV light away from our precious beer.

We keep making delicious craft beer at Cowbell, and we continue to innovate ways to improve our process, efficiency, and the beer. It’s all in the details, folks.

Come see for yourself at The Cowbell Farm.


Appendix 1.1

Glass in a standard window

Visible light Transmission = 82%

Solar Heat Gain Coefficient = 0.78

Glass Temperature Winter = 45°F

Glass Temperature Summer = 90°F

UV transmission = 58%

U Value = 0.46

Glass in Cowbell LoE3 – 366 Windows (west wall)

Visible light Transmission = 63%

Solar Heat Gain Coefficient = 0.27

Glass Temperature Winter = 56°F

Glass Temperature Summer = 83°F

UV transmission = 5%

U Value = 0.20 (lower number = more efficient)