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BU:GU Ratio

I’ve been reading a bit about the BU:GU ratio lately and am paying attention to it in my recipes by checking it against style at Mad Alchemist: Beer Style Bitterness Ratios (BU:GU) .

I’ve read a few posts on the forum, this one throws in apparent attenuation: Relative Bitterness Ratio (RBR), however haven’t noticed inclusion in the discussions about recipes and it being very important. I am curious if folks are looking at it and how much importance they are assigning to it? Thanks!

I think BU:GU is just as useful as IBUs themselves. It’s another way of looking at things, from a perspective of balance.

I am not sure people can actually taste attenuation or lack thereof, except in extreme cases (extremely low or high), so I’m not certain how useful that factor would be to include with the ratio. Mash temperature experiments by Brulosophy and others have failed to achieve significance in many cases, where final gravities were very different but the beers still tasted exactly the same or almost.

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Thanks! I need to take a look at my earlier recipes in terms of balance. I know they were lacking something, couldn’t put my finger on it though. Maybe it was balance since I didn’t consider it.

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I utilize the BU:GU ratio in every recipe I develop. I think it’s essential whether you want a beer to be super hoppy, balanced, or malty; even for styles like IPA that have preconceived “styles.”

:dizzy_face:, I see it alot through some of the more detailed info I read… I aint there yet… Perhaps Loopie can give us a brief descriptor of how and why its a process to incorporate… Sneezles61

In brief, BU:GU is a balance number where you divide the IBUs by the gravity points to the right of the decimal, e.g., take a beer with an original gravity of 1.060, knock off the 1.0, and you have 60 gravity points or GU. If the same beer also has 60 IBUs, then the BU:GU ratio is 60:60 = 1.00.

Now if a similar 1.060 beer had only 30 IBUs, then the ratio is 30:60 = 0.50.

In general, BU:GU values of about 0.50 are considered “balanced” with respect to bitterness vs. malt. Most IPAs, on the other hand, will have values >1.00, to a practical maximum of around 1.15-1.20 (above that and it’s turning into hop soup a la NEIPA). And then on the other-other hand, a malty beer such as a Scottish ale or other low hopped beers like hefeweizen may have a lower ratio of just 0.25-0.30.

This ratio can be very useful for recipe design. If you know you want a beer that is a little more towards the malty side, and you want it to be about 6% alcohol, you may wish to set your BU:GU ratio a little lower than 0.50, maybe at 0.40, and set the original gravity at 1.060 (another shortcut rule is that you’ll get roughly 1% ABV per 10 BUs). With this knowledge, you know you want BU:GU = 0.40 = X/60. Solving for X, you get 24. So you should aim for about 24 IBUs to get the amount of balance you want.

That’s how I use BU:GU. And there are tables online that give the ratio for each well known style, to give you an idea of how well balanced they are between hops and malt.

Hope this helps. Cheers.


Thanks for the clear summary! I don’t recall if it was covered in Palmer’s book but now that I’ve “discovered” it, I’ll certainly take it into account for my recipes.

Well explained @dmtaylo2. To build on that, say you have a beer you want to have a little more bitterness. In this example we’ll use an Irish Red. The BU:GU is .561. You can lean on the bittering addition and bump that ratio to .650. This to me is why the ratio is important. It gives you an idea of where you want to start.


BRAVO! This now helps me to see it more clearly… I’ve got to play with the numbers so I better follow… Does the salt additions change this up much then? Perhaps I ask too much… Sneezles61

Not from what I read but I’ll defer to the experts.

I’ve also recently discovered this ratio while reading Designing Great Beers. I certainly plan to keep it in mind for now on.

You certainly can also influence perceived bitterness by altering water. Use gypsum for a drier, more bitter beer or use Calcium Chloride for a rounder, smoother beer. Of course, you’ll need to understand your water and what you’ll need to reach your mash pH, but decide where your Ca levels come from with those two ingredients.

I know in other posts you mentioned understanding CaSO4 (gypsum) and CaCl2 (Calcium Chloride). In traditional IPA, the water is high in CaSO4 fir the drier bitterness. In the NEIPA the water is more rich in CaCl2. This lends to the lower bitterness with that founder smoother flavor. Couple that with oats and wheat as well as extreme late hopping methods and you’ll have a “juicy” and hazy beer. IMO the haze is coming from the ingredients since I’ve had the NEIPA yeast drop crystal clear on a number of beers.


Thank you Loopie! My next tinkering is to add the CA to the boil for hop accentuation, and I know if the buffering isn’t too much, it should lower the pH… I’ll use the acid only for the mash pH… again just tinkering, and now this BU:GU should help to bring my simple knowledge full circle! Sneezles61

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Good seeing you around again. The forum has missed your inciteful and sometimes colorful contributions.

Water chemistry wouldn’t really affect the BU:GU but could definitely affect the perceived bitterness, flavor and aroma of the finished beer.

edit: Yea what @loopie_beer said.

I’ve never really used the BU:GU in my recipe formulation. I’ve used the sytle guidelines in Beersmith2 to target and refine balance. I’m glad this topic came up though. I may play with it in relation to a few beers I’m refining.

I agree.

I wouldn’t have thought of using a higher concentration of calcium chloride in a NEIPA because it would tend to accentuate clarity but it would also have the affect on mouthfeel that you mention.

At risk of being in the wrong pew but since the topic came up, the grist for an neipa I’m going to make is:
9# two row
1.75# each of white wheat and flaked oats
.75 carapils
1# rice hulls

Using WLP008
Bittering fw 1.5 Magnum
1 each of Simcoe, Amarillo, Mosaic at 15, FO, and 7 days.

BU:GU is .88 which makes me a conformist. Color will be super pale which is what after as well and makes me a nonconformist. Thoughts?

Moved that branch of discussion to the recipe swction

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