BU:GU Ratio and adjuncts?

[luckybeagle]

Hi there,

I've always been curious about how much trust I should place in the BU:GU ratio when adding adjuncts, such as table sugar or candisyrup?

For example, if I brew a Patersbier to 1.044 and get 12 IBU, I'm at 0.28 BU:GU, which is more in line with hefeweizen and verges on "extra malty/cloying" by most beer standards. However, when I back out the 1 lb of table sugar that I add, the BU:GU goes up to 0.38, which is much more balanced.

La Trappe Quad's BU:GU ratio stands out to me as one that defies the ratio math as well. Here are its approximate numbers:
OG: 1.086
IBU: 18
BU:GU ratio: 0.20

This beer has 3 pounds of D-90. When I back that out, the BU:GU ratio jumps to 0.32.The pre-syrup gravity would be about 1.055 as well. This is not a particularly sweet beer, either--and I feel a 0.20 BU:GU ratio in an all-malt beer would be sickly sweet.

So.. do we just pretend the sugar isn't there when running these ratios, since it ferments out fully in most cases?

 

[Alan Reginato]

Hi there,

I've always been curious about how much trust I should place in the BU:GU ratio when adding adjuncts, such as table sugar or candisyrup?

For example, if I brew a Patersbier to 1.044 and get 12 IBU, I'm at 0.28 BU:GU, which is more in line with hefeweizen and verges on "extra malty/cloying" by most beer standards. However, when I back out the 1 lb of table sugar that I add, the BU:GU goes up to 0.38, which is much more balanced.

La Trappe Quad's BU:GU ratio stands out to me as one that defies the ratio math as well. Here are its approximate numbers:
OG: 1.086
IBU: 18
BU:GU ratio: 0.20

This beer has 3 pounds of D-90. When I back that out, the BU:GU ratio jumps to 0.32.The pre-syrup gravity would be about 1.055 as well. This is not a particularly sweet beer, either--and I feel a 0.20 BU:GU ratio in an all-malt beer would be sickly sweet.

So.. do we just pretend the sugar isn't there when running these ratios, since it ferments out fully in most cases?

No, because alcohol is sweet. You can use RBR, relative bitterness ratio, for those beers.

 

[Miraculix]

The ratio thing is crap if you ask me.

Just design a recipe and ask yourself the question how bitter you would want it to be.

I recently brewed a tropical stout with under 20 ibus. It came out beautiful with an og above 1.06.

It all depends on your taste and the recipe design, the ratio does not account for that so it's useless

 

[dmtaylor]

This is a very interesting question! After a bit of pondering, I do think it's best to exclude the sugar in the BU:GU calculation as you suggest. The fermentation of the simple sugar really does change the balance away from sweetness to a significant extent, which would tend to increase the BU:GU perception. It makes sense that this would be of particular benefit for Belgian ales which tend to be very well attenuated, especially saisons that can finish very dry, below 1.005. Not much sweetness left there, regardless of OG or IBU.

 

[DBhomebrew]

BU:GU is rather crude, but it's helpful when looking at recipes within a style.

There's another method to reflect sweetness/bitterness balance, I don't recall what it's called. It takes into account attenuation and such.

ETA: Relative Bitterness Ratio

 

[luckybeagle]

Great and insightful discussion!

I actually completely forgot to consider apparent attenuation--that makes sense. Just as dmtaylor said above, a beer finishing at 1.020, for example, will be sweeter than a bone-dry Belgian Golden Strong finishing at 1.003, hopping/BU:GU ratios the same, due to residual sweetness.

I hadn't heard of RBR--now I've got some reading and geeking out to do. I don't know what WY3787 is going to give me in terms of AA--it's been a good year since I've brewed with it, but since table sugar makes up 13% of the overall grist weight in this recipe, I'll assume mid-80s. I'm pretty sure that's what I got with my last Enkel:

Father's Reward Enkel
My results from yesterday's brew:
OG: 1.044
IBU: 13
AA: ~85%
BU:GU of 13/44 = 0.295

Plugged into the RBR formula:

RBR = (BU:GU) x (1 + (ADF - 0.7655))
RBR = (13/44) x (1 + (0.85 - 0.7655))
RBR = 0.29 x (1 + 0.0845)
RBR = 0.29 x 1.0845
RBR = 0.3145

Marginally more balanced than the 0.29 BU:GU my software was calculating, yet considerably sweeter than the 0.38 number I was getting when I backed out the sugar addition entirely.

Applied to the La Trappe Quad numbers, I come up with an RBR of .21. Interesting because, again, I don't find this beer to be cloyingly sweet, but both RBR and BU:GU ratio, considering the full grain bill and adjuncts, would suggest that it is. And it finishes at a not dry gravity of 1.014. After backing out the 3# of candisyrup, the RBR is 0.34. The RBR would be a little lower if I could plug in the apparent attenuation numbers based on an all malt recipe vs one with adjuncts, but that's still a huge difference and would suggest that gravity derived from sugars maybe shouldn't be weighted nearly as heavily as gravity from grain?

Considering it further as related to Alan's post:

No, because alcohol is sweet. You can use RBR, relative bitterness ratio, for those beers.

Alcohol IS sweet, but what amount of perceived sweetness in beer is derived from alcohol directly vs from unfermentable sugars, grist makeup, etc? Does alcohol in itself require the same amount of hopping to create balance? For example, is an adjunct-free 5% ABV beer with a "balanced" 0.5 BU:GU going to be noticeably less sweet than a 6% ABV beer with the same ratio? I ask because 1 lb of table sugar added to a boil/fermenter will ferment out 100%, and will add about 1% ABV to a 5 gallon batch, but does not add sweetness by itself--only alcohol. This skews the ratio down, but theoretically would not impact perceived sweetness. Would ~7 gravity points derived from additional base malts, not offset by ~3.5 IBU--following the 0.5 ratio above--produce a sweeter beer? I think it would.

It's a shame that MadAlchemist's website, where a bulk of this research and insight appears to be published, is down. I did find this quote on the Beersmith forum. I don't use that software or belong to that message board, but I thought this was an interesting take as well:

BOB357 says: "[RBU] is a formula that's applied to the IBU/SG ratio based on the apparent attenuation of a fermented beer. Pretty useless, IMO, since hop utilization models are educated guesses. Start with a guess = end with a guess."

With that logic, BU:GU ratios would also be useless. Assuming they're not, and after thinking out loud in this post, I'm sort of leaning toward the idea that calculating bitterness via the RBU method, since it takes AA into account, and before 100% fermentable adjuncts are added, might be more reliable than including them in the overall calculation.

 

[BrewnWKopperKat]

It's a shame that MadAlchemist's website, where a bulk of this research and insight appears to be published, is down.

Check the Internet Archives: Mad Alchemist: Relative Bitterness Ratio (RBR)

 

[hotbeer]

I use the BU:GU ratio to help me get the hop amounts more correct when adjusting a recipe to be a lower ABV beer.

It seems to help for that. But I haven't seen a need for using it for other things.

But I might suppose that if you are for some reason adding or changing the amounts sugars to a recipe that didn't call for that then there might be some reasoning to trying to keep the same BU:GU ratio in hopes of getting a similar hop character for the beer even though once you change the recipe, it's not the same beer.

 

[hottpeper13]

I found out about the ratio in Ray Danial's book and use it only as a guide to getting the right balance in different styles.
When developing a new recipe it comes in handy to get you close on the first try. I know my yeast and that the Belgian beers are going to finish ~1.002 and I include all the sugar in calculations. My Blonde finished at 1.001 with a SG of 1.056 which give me .37. It has the bitterness of a Pale Ale,so very balanced.