# Bu:gu Ratio And Balance Value



## whitegoose (21/4/09)

Okay so I'm trying to get my head around BU:GU and how I can use it to refine my recipes. I've read this page and underatnd it at a basic level, but I can't quite get how to apply it...

eg.
I have a recipe for an brown ale. Using ianh's spreadsheet to do the calculations I have the following for my brew:

Yeast Attenuation	0.75
BU:GU	0.68
BV	1.47
Calculated IBU	25.9

And apparently the BV for the style "English Northern Brown Ale" is 1.18​Does it mean I off the style because my BU:GU is a way off the BV? Is that the idea? To get them the same?
Or... Is this just saying that my brew will end up quite sweet (low bitterness to gravity), and the BV of 1.47 just means I would have to add quite a lot of bitterness to balance out the sweetness?

Can someone try to give me layman's explanation of what these numbers mean for my brew, and what if anything needs to be done to make it better suit the style? Or is it looking okay?

edit: I did search but the search engine doesn't like "bu:gu" apparently


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## ianh (22/4/09)

whitegoose said:


> Okay so I'm trying to get my head around BU:GU and how I can use it to refine my recipes. I've read this page and underatnd it at a basic level, but I can't quite get how to apply it...
> 
> eg.
> I have a recipe for an brown ale. Using ianh's spreadsheet to do the calculations I have the following for my brew:
> ...



It suggests that recipe is overhopped for the style. If on the spreadsheet you look at the graph to the right of this data you will see a blue dot for the style and a red dot for the recipe. In this case the red dot will be in the very hoppy area where as the style dot is just on the hoppy side of balance.

If you have everything else "good" for the recipe, the spreadsheet calculates an estimated IBU value to match the recipe style. However because of a number of factors, will you in practice get what the spreadsheet predicts.

I would suggest that you reduce the hops slightly to get nearer the predicted value. Experience will then be your guide. I have already stopped using the Hop Concentration Factor but have inceased my boil volumes from 4 to 10 litres and I am currently looking at increasing them further.

Still learning.

cheers

Ian


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## Screwtop (22/4/09)

whitegoose said:


> Okay so I'm trying to get my head around BU:GU and how I can use it to refine my recipes.



The BV formula is something I have applied to my brewing for around 12 months. The most important factor in applying the BV formula is having a reasonable expectation of being able to predict OG and more importantly FG as the formula depends upon these figures for accuracy. This generally means a good understanding of the recipe (based upon previous batches) or your system, ingredients, yeast strain and health, mash regime and fermentation temperature control. Inclusion of dextrinous malts in the grist will increase FG as will higher Sacc temps and differing mash regimes. Lets say you are confident of predicting OG , start with maximum attenuation for your yeast strain say 75%. Now look at your grain bill, maybe there is 15% of cara/crystal malt in the bill, to compensate for this reduce your yeast's attenuation figure a little, (the little comes from experience sorry). If we guess at 72% attenuation and the yeast is in good nick and you have fermentation temp control then this should be achieveable.

Now we need to calculate the RTE for the recipe. You know your predicted OG lets say it is 1.048 and the predicted attenuation of 72% should give you a predicted FG. ((OG-1)-((OG-1)xAA%))+1 or ((1.048-1)-((1.048-1)x72%))+1 = 1.013 

You now have a predicted FG to apply to the RTE Formula. RTE = 0.82 x FG + 0.18 x OG or (0.82 x (1.013-1)x1000)+(0.18 x(1.048-1)x1000) = 19.66

And you can now apply the RTE to the Balance Value formula. BV = 0.8 x BU / RTE or 0.8 x BU from your recipe / RTE or 0.8 x 25.9 / 19.66 = 1.074

Make yourself up a simple little spreadsheet to do the calcs and adjust the bitterness level until you get to the suggested BV for the style. You can then adjust the hops in your recipe to match the calculated BU's

Hope all of this waffle is understandable. I have lots of BV streadsheets and databases that I use for calculating BV, none of which are double checked for errors or finished (I never finish any project, they remain in development), PM me if you would like a copy.

Cheers,

Screwy

EDIT: Thought I might simplify by saying that Balance Value takes into account the finishing gravity of the beer, unlike the BU:GU ratio. I like it as a way of balancing to the sweetness in your finished beer, I use a little yeast assistance (sugar) in some styles which increases yeast attenuation, nothing worse than the puckering bitterness of beer that finishes at 1.007 and has been bittered to finish at 1.014 I am able to predict the finishing gravity and use the BV formula and balance sweetness/bitterness. Remember that the BV values are arrived at by averaging the OG, FG and IBU for each beer style. BV will put you in the ballpark but then it is up to you the brewer to adjust for YOUR beer.


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## whitegoose (22/4/09)

ianh said:


> It suggests that recipe is overhopped for the style.


Okay cool - is that because the BV for the style is lower than the BV for my recipe? I'm trying to work out what the relationship between all the numbers is?



Screwtop said:


> Thought I might simplify by saying that Balance Value takes into account the finishing gravity of the beer, unlike the BU:GU ratio. I like it as a way of balancing to the sweetness in your finished beer, I use a little yeast assistance (sugar) in some styles which increases yeast attenuation, nothing worse than the puckering bitterness of beer that finishes at 1.007 and has been bittered to finish at 1.014 I am able to predict the finishing gravity and use the BV formula and balance sweetness/bitterness. Remember that the BV values are arrived at by averaging the OG, FG and IBU for each beer style. BV will put you in the ballpark but then it is up to you the brewer to adjust for YOUR beer.


Okay so I think I'm getting it a bit more... BV and BU:GU are related, but are totally independent of each other - there's no point in comparing them to each other. Is that correct?

So I can compare the BV of my recipe to the suggested BV of the style... what does the BU:GU tell me? Just that it is a sweet or bitter beer? Do I even need to pay attention to it?

Thanks for the help guys, sorry if I'm being a bit slow


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## whitegoose (23/4/09)

whitegoose said:


> Okay cool - is that because the BV for the style is lower than the BV for my recipe? I'm trying to work out what the relationship between all the numbers is?
> 
> 
> Okay so I think I'm getting it a bit more... BV and BU:GU are related, but are totally independent of each other - there's no point in comparing them to each other. Is that correct?
> ...



Anyone?


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## buttersd70 (23/4/09)

BUGU is the relationship between the bitterness level of the beer to the initial gravity. It is simply IBU/OG. BV, on the otherhand, takes the final gravity into account, as screwy said....so it accounts for the fermentability of the wort.

As an example, comparing the two; for an AG wort of "average" gravity, mashed at "average" temperature (therefore giving it an "average" fermentability, and fermented with an "average" yeast, the difference between the BUGU and the BV will be in the region of 1:2 (ie, the BV scale will work out to be _roughly_ double that of the BUGU). However, if you were to use a different yeast, lets say one that attenuates lower than "average", the difference becomes noticable....if in addition to that, you were to mash at a hotter temperature of say 70C (or in the case of extract or kit brewing, you were to use non fermentable, or low fermentable adjuncts, such as maltodextrin, for example, or higher than usual amounts of specialty malts, giving high levels of dextrins), then the resultant fermentability of the wort would be even less to begin with, so the difference between BUGU and BV would be even greater.
The same applies in reverse, if you were to use a high attenuating yeast, mash cooler, and/or use a lot of simple sugars.

The "balance" point, where hop bitterness and malt sweetness are roughly level, with neither dominating, is around 0.5 BUGU, or 1 BV. Each style of beer is basically "out of balance", for want of a better term, by a given amount, allowing either the bitterness, or the malt sweetness, to dominate.

So, as an example, lets say you have a wort made out of extract, 1 tin of goop and 1 kg of ldme, with an OG of 1040, and 20 IBU. Lets say for the sake of the example that the FG is 1010.

According to BU:GU, the BUGU is 0.5. So on the BUGU scale, it is at the balance point, with neither the hops nor the malt dominating.

According to the BV scale, the BV is ~ 1.04. So theres not a lot of difference there, BV is approximately 2X BUGU.

This would give you an apparant attenuation of 75%, and would be somewhat similar to what you could expect from US05, for example. Lets say you were to do the same beer, but replace the yeast with something that is fairly low attenuating. Lets say WY1469, which gives apparant attenuation somewhere in the region of 65-69%. Lets say 67% for the example......

The BUGU remains unchanged, because it doesn't take into account final gravity. But the BV will change...at 67% apparant attenuation, it would end up at FG of approximately 1013 instead of 1010. Now this obviously will result in a sweeter beer from the prior example, because there is more unfermented sugars left behind.....the BV in this case would be ~ 0.89. So in this case, the malt is now dominant to the hops. If you wanted your beer with the 75% US05 to have the same relative biterness as the beer with the 67% WY1469, you would need to hop the second beer aproximately 3 IBU more, to end up with the same BV (if that is, in fact, what you want to achieve). Or alternatively, replacing some of the ldme with simple sugar, so that the attenuation averages out to the same. In mash brewing, this is achieved by using different mash temperatures, to give a slightly more fermentable wort (unless of course, you were after the additional body in the first place; in which case you would increase the IBU as previously mentioned).  

The BUGU will give you a ballpark figure of where, roughly, you need the bitterness levels. The BV will allow you to fine tune the balance.

Hope that makes sense.


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## ianh (23/4/09)

whitegoose said:


> Okay cool - is that because the BV for the style is lower than the BV for my recipe? I'm trying to work out what the relationship between all the numbers is?



Yes. BV for style 1.18 recipe 1.47 suggests it's overhopped for that style. As previously mentioned check the graph to the right of your data on the spreadsheet. The red dot for the recipe is probably in the very hoppy section of the graph. As you reduce the bittering hops (60 mins) the IBU will come down which in turn will reduce the BV.

In a perfect world the calculated IBU value would give a recipe BV value which agrees with the style BV. But because of all the variables
in acheiving a set bitterness level I would reduce the bitterness hops a little to get nearer the BV value and then use that experience when formulating the next brew.

Butters has already provided a much better explaination of the numbers than I could.

cheers

Ian


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## Cortez The Killer (23/4/09)

Here's a spreadsheet I set up to do the calcs based on the article you cited

Cheers 

View attachment balancing_value.xls


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## whitegoose (24/4/09)

Thanks for all the help guys, appreciated muchly


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