BU:GU Ratio

[ajr1]

Wouldn't it make more sense to use the final gravity in this ratio? Since that's whats left over from the fermentable sugars. It seems to me at least that would have a bigger influence over the perceived bitterness or maltiness of the beer

 

[Qhrumphf]

One calculation I've seen does this by taking a BU:GU ratio and then adjusting further by weighting against "average" apparent attenuation (I think it used 75%). Lower apparent attenuation (and higher FG) would drive it down and higher apparent attenuation/lowe FG would drive it up.

 

[Smellyglove]

You are correct. It would be a better measure. But, we often don't know the FG, even if we can ballpark it pretty good. I still use BG as a measure when I'm compiling "new" recipies and it sort of checks out pretty good if the FG is within range of what's acceptable for that style. Maybe you can go "better"/more accurate with it, but you can't go wrong unless you botch something. I feel it's pretty fail safe route to go.

 

[jwalk4]

Final gravity has more to do with the attenuation of the yeast and mash temp (enzyme acitiviry), than recipe formulation.

I suppose you could use FG. You'd just have to create your own scale: ex. Two beers finish at 1.010, one is a mild hopped to 15 IBU and one is a pale ale hopped to 30. So the ratios are 15:10 and 30:10, respectively. I think you'd just have a hard time explaining what those results mean.

 

[Weezy]

It must be OG otherwise it loses its meaning and usefulness.

Let's take your imaginary favorite pale ale...1.050 and 30 IBUs. BU:GU=0.6
It's your favorite because you like that balance of malt to hop flavor and aroma. i.e. you like pale ale at BU:GU of 0.6

If you want brew an imperial version of that pale ale, say 1.080, you use the BU:GU 0.6 to determine what IBUs to target. 80 x 0.6 = 48 IBUis. Will give you a similar malt-hop balance as the 1.050 beer. The hops had to go up to balance out the increases malt. If you just stick with 30 IBUs, it will not have enough bitterness and the beer will come out too hoppy.

The ratio has no similar meaning if used with FG. I can get an imperial IPA to finish dryer than a 4% English mild all day long.

The point being is that the ratio will give you a frame of reference for each beer style. For IPA maybe you 1.2, for British small beers maybe you like 0.4, etc.

When Ray Daniels came up with the idea, people weren't brewing hop bombs. BU:GU is very useful on more traditional beer styles.

 

[Qhrumphf]

Our must be OG otherwise ir loses its meaning and usefulness.

Let's take your imaginary favorite pale ale...1.050 and 30 IBUs. BU:GU=0.6
It's your favorite because you like that balance of malt to hop flavor and aroma. i.e. you like pale ale at BU:GU of 0.6

Id toy want Rio doe as imperial version of that pale ale, say 1.080, you use the BU:GU 0.6 to determine what IBUs to target. 80 x 0.6 = 48 Unis. Will give tout a similar effect as the 1.050 beer. The hops had to go up to valence or the increases malt. If you just stick with 30 IBUs, it will not have enough bitterness and the beer will come out too hoppy.

The ratio has no similar meaning if used with FG. I can get an imperial IPA to finish dryer than a 4% English mild all day long.

The point being is that the ratio will give you a frame of reference for each beer style. For IPA maybe you 1.2, for British small beers maybe you like 0.4, etc.

There's some truth to both. Because the OP is correct that the residual sweetness and body also have an impact. Say you adjust mash temp such that the same beer finishes at 1.008 instead of 1.014. The difference in balance will be huge, and the bitterness far more apparent. But as you said, simply going by FG is an even worse metric.

Only decent way I've seen is account for both is to factor your ratio by attenuation as I expressed above.

HOWEVER...

No matter what we're doing, unless you're getting lab analysis done, your IBU numbers are never more than an estimate, so deriving too much math from an unreliable number is rather foolish. This is especially true when folks aren't paying attention to hop alpha acids and just going by seldom accurate presets.

Ultimately experience on what X calculated IBUs (via a consistent formula- I always use Tinseth) in Y original gravity and Z final gravity TASTES like on YOUR system and process and adjusting for the future is the best you can reliably do.

 

[Denny]

Do it whatever way you like. It's all relative to your tastes.

"HOWEVER...

No matter what we're doing, unless you're getting lab analysis done, your IBU numbers are never more than an estimate, so deriving too much math from an unreliable number is rather foolish. This is especially true when folks aren't paying attention to hop alpha acids and just going by seldom accurate presets.

Ultimately experience on what X calculated IBUs (via a consistent formula- I always use Tinseth) in Y original gravity and Z final gravity TASTES like on YOUR system and process and adjusting for the future is the best you can reliably do."

Absofreekinlutely! Here's an interview with Glenn Tinseth where he basically says it's a crap shoot....https://www.experimentalbrew.com/experiments/writeups/ibu-lie-kind

 

[ba-brewer]

Wouldn't it make more sense to use the final gravity in this ratio? Since that's whats left over from the fermentable sugars. It seems to me at least that would have a bigger influence over the perceived bitterness or maltiness of the beer

Someone wrote up a article called a relative IBU/SG ration that take the fg into account.
http://www.madalchemist.com/relative_bitterness.html

 

[Qhrumphf]

Someone wrote up a article called a relative IBU/SG ration that take the fg into account.
http://www.madalchemist.com/relative_bitterness.html

Ahh that's actually the source I was referring to without bothering to look it up. Thanks!