Blinded by Science: Know Your Numbers!


October 9, 2015 by fhsteinbart

Here we see the relationship graphically of BU:GU.

Here we see the relationship graphically of BU:GU.

As more home brewer’s eventually learn, math and cleaning are the two most essential parts of brewing beer. Math is needed to elucidate the physiochemical aspects of brewing, namely using the hydrometer to find out your original (OG), and terminal (TG) gravities. Without these numbers, it’s nearly impossible to know how much alcohol was produced. Cleaning and sanitizing is essential as they keep your brewery free from unwelcome guests that would be more then happy to infect your brewery with their metabolic byproducts, most of which don’t taste very good. If you have a stainless steel system on the cold side (fermenters, aging tanks, corny kegs, etc.) then some form of percarbonate cleaner followed by an iodinated sanitizer would suffice. For those who use glass and/or plastic, there is still a similar regimen with using a percarbonate cleaner such as PBW, One-Step, or Craft Meister, followed by a surfactant carrying sanitizer like Star-San. Contact times vary with sanitizers, so make sure to read the fine print on their use, but I’ve found that a fifteen minute contact time to be advantageous in so much that it reduces microbial content to essentially nil. Of all the numbers that should be in every home brewer’s tool kit, the most important one is the balance between bitterness and gravity or BU:GU. This not only helps with recipe formulation, it also gives you and idea on where the balance of the beer is at. For example, an IPA might be at 1:1 for bitterness to gravity, but a Pale Ale would be somewhere around 0.75:1, and a Porter at nearly 0.5:1, and a Golden Ale or Blonde Ale at 0.33:1.

Here we see a curve of hop utilization over time and OG.

Here we see a curve of hop utilization over time as shown by HPGLC analysis.

I’ve also found out that increasing the carbonation in proportion to the decrease in bitterness lends itself to a more balanced, and therefore more drinkable beer. This is what makes lower hopped beer styles like Hefeweissens, Belgian Dubbels and Tripels, and Wheat style beers so very enjoyable, despite their apparent lack of bitterness as compared to other more hoppy beer styles. This is why British beers always seem to taste better when served on cask as Real Ale (a subject that we’ll be dealing with in another installment) rather than carbonated to a higher V/V ratio of gas. Oh, that reminds me, volumes of CO2 (aka carbon dioxide) can markedly shift the flavor profile of a beer significantly. So if you have a beer on tap that’s a tad too malty, or is just underhopped, try goosing up the gas a few volumes to try to recover that balance. If you bottle, and know beforehand that the beer needs to be hoppier, then by all means add some more corn sugar for the carbonation to increase, but not so much that the bottle cannot retain it and fail catastrophically. If you’re ever in doubt, you can always ask anyone at the store or if I’m on duty, we’d all be more than happy to answer any questions that you may have in this regard. Hope this little thumbnail sketch helps, and hoppy brewing!


2 thoughts on “Blinded by Science: Know Your Numbers!

  1. Caryn says:

    I think this is among the most vital information for me.
    And i am glad reading your article. But wanna
    remark on few general things, The website style is perfect, the articles
    is really excellent : D. Good job, cheers


    • fhsteinbart says:

      Thank you very much for your support! I work hard each and every week to come with both cool and useful information that no one else is doing in the world of beer blogs. If you have any suggestions on what else you’d like to see, I am always open to suggestions! Hope that you all have a great Thanksgiving, and are enjoying it with awesome craft beer!


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