I’m not a statistician, so this is a bit of a stretch for me. But I’m posting this information because the internet is smarter than I am.

Last week, in the discussion of my post about what certain numbers (Specific Gravity, IBU, etc.) mean about your beer, the idea came up to make what amounts to a simplified statistic about beer – a way to represent, more simply, what people really want to know about their beer. It goes along with the pipe dream of having breweries print statistics about their beer on the labels.

The theory, in my mind, is that nobody wants to pick up a beer and think, “1.056 and 1.010 with 60 IBUs.. hrm… that’s pretty bitter.” Some beer geeks can do that in their heads, but a lot of people can’t, or don’t want to. On the other hand, if you could pick a beer and say, “A hoppiness rating of 92? Good heavens! That’s big!” it would be pretty cool.

So, I’ve been playing with numbers a wee bit. Mostly collecting them. I started with the BJCP Style Guidelines. I recorded the maximum and minimum stats for OG, FG, and IBUs and calculated what the average beer would look like in each style category.

For example, for English IPA the style range shows:

OG: 1.050 – 1.075
FG: 1.010 – 1.018
IBU: 40 – 60

Thus, the average English IPA would be:

OG: 1.063
FG: 1.014
IBU: 50

This is just to give a basic sample range of beers to work with that should be fairly representative of all the styles involved, though I’ve considered removing sour styles from this exercise, since Lactic Acid kind of fouls everything up on the whole, “This is what flavor you should expect” front.

I also calculated apparent attenuation for each style – finding out how much sugar has been fermented out from each on average.

(GU – FU)/GU

The Average English IPA listed above has an Apparent Attenuation of 77.60%. In other words, 77.6% of the sugar in the solution has been converted to alcohol. In reality, that’s not quite right, since alcohol is lighter than water and this is being calculated by the density of the liquid. You can ferment down to a final gravity lower than 1.000. However, for this purpose, this calculation should be good enough.

Then, I made what I’m (currently) referring to as a “hoppiness score.” It’s on the same line as a GU:BU ratio, but instead what I did is divide IBU by GU, then multiply it by 100 to give us a nice round number that we can related to instead of a decimal. The theory is that the more hops there are in comparison to original gravity, the higher this number would be. It should correspond with how hoppy the beer is. It works fairly well.

The English IPA up there would have a hoppiness score of 80. Is it an arbitrary number? Sure. Work in progress. Bear with me.

Then I applied apparent attenuation. It was noted in the discussion that the more dry a beer is, the more bitterness would be apparent to the drinker. I agree. To account for this, I multiplied the hoppiness score by the apparent attenuation. I called this “Apparent Bitterness.” I figured that the drier a beer was, the higher the apparent attenuation would be and so the closer the “Apparent Bitterness” would be to the Hoppiness Score. In the full list of styles, it does what I was hoping for and tends to give styles in which you would expect more bitterness a higher score.

Here’s the list I was working from sorted by Hoppiness Score:

And the same chart sorted by Apparent Bitterness:

It’s not quite right, but it’s definitely headed in the right direction. I would love to hear from anybody who has different ideas on how to represent these numbers, and you can damn well bet that I’ll be posting more as I fiddle around with math.

Maltiness coming soon, it’s a lot more challenging.

[Head on over to Part 2]

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