12 replies to this topic

[Mya]

[quote name='Matt C' date='04 September 2010 - 09:19 AM' timestamp='1283617183' post='502543']I am still perfecting my new house recipe and this time i think the IBUs will be about 4 IBUs short.How perceivable is 4 IBUs? Will you be able to tell much if any difference between 4 higher or 4 lower?[/quotewell I guess that is relative4 +/- IBU on 40 IBU APA nah no biggie4 +/- IBU on a 15 IBU Cream Ale yeah you might notice it

[jayb151]

well I guess that is relative4 +/- IBU on 40 IBU APA nah no biggie4 +/- IBU on a 15 IBU Cream Ale yeah you might notice it

Yea, I think That's right. You should think about it more like percentages. If you're off 4 IBU on a low IBU beer, then the percentage is way high and you'll most likely know it. But if you're 4 IBU of on a hop bomb, you're not going to notice much. Are you 5% off, or 25% off?I also think there is a plateau. Once you get past a certain amount of bitter, it's just bitter.What kind of beer was it?

[Big Nake]

You know what always gets me? That IBU calculation seems to be a seriously varying thing. I realize there are different calcs out there, but I'll see someone post a 5-gallon recipe with 1.5 oz of one hop at 7.5% for 60 minutes and an ounce of this hop at 6% for 30, then 2 ounces at 7% for 15 and more hops later and the IBUs in the recipe are 21 or something. No way. Either I'm reading it wrong or there are wild variances in IBU calculations. Anyway, I agree that 4 IBUs is different at different levels of overall IBUs. In most of my beers, 4 IBUs could make a big difference. Cheers.

[tag]

Yeah. ProMash has 3 different calcs. And hops change over time. And some hops are more harsh.Probably the best way to do it is to find the calc that fits your taste the best and then go by your taste.

[jayb151]

Anyway, I agree that 4 IBUs is different at different levels of overall IBUs. In most of my beers, 4 IBUs could make a big difference. Cheers.

Yea Ken, You make some mighty fine beer but I'll say that every one I've had is expertly balanced. I also think your beer highlights more soft and subtle qualities so for you, 4 IBUs is a lot. You're right though. There are different calcs out there. Every brewer just needs to find one that is consistent on their system and stick with it.

[MtnBrewer]

I am still perfecting my new house recipe and this time i think the IBUs will be about 4 IBUs short.How perceivable is 4 IBUs? Will you be able to tell much if any difference between 4 higher or 4 lower?

I've read that 5 IBUs is right at the threshold of perception. So I wouldn't worry about a 4 IBU variance.

You know what always gets me? That IBU calculation seems to be a seriously varying thing. I realize there are different calcs out there, but I'll see someone post a 5-gallon recipe with 1.5 oz of one hop at 7.5% for 60 minutes and an ounce of this hop at 6% for 30, then 2 ounces at 7% for 15 and more hops later and the IBUs in the recipe are 21 or something. No way. Either I'm reading it wrong or there are wild variances in IBU calculations. Anyway, I agree that 4 IBUs is different at different levels of overall IBUs. In most of my beers, 4 IBUs could make a big difference. Cheers.

You might be overly generous by referring to it as a calculation. It's really an estimate based on a model and there are several models to choose from. So it's no wonder that the results vary the way they do.

[MakeMeHoppy]

Well the OG is 1.056 at 21.6 IBUS's with a 0.400 IBU/SG ratio.

I'm not sure I'd measure IBU in 1/10's the hops if tested are tested in a lot and usually the AA is expressed in a range anyway. I doubt you'd tell the difference in your recipe. Do you measure your wort volume to that degree as well?

[Malzig]

I've read that 5 IBUs is right at the threshold of perception. So I wouldn't worry about a 4 IBU variance.

I've heard the same thing many times, that the human ability to resolve two beers of different bitterness is about 5 IBU. So 21.6 and 24.5 IBU shouldn't be discernibly different. Even if you are a super-taster and can tell the difference, I don't think that difference is going to matter in a 1.055 beer.As far as the IBU estimates, I've also seen data that found that two brewers brewing from the same recipe can have laboratory measured IBUs 25% to either side of the prediction from the calculation.

[MtnBrewer]

As far as the IBU estimates, I've also seen data that found that two brewers brewing from the same recipe can have laboratory measured IBUs 25% to either side of the prediction from the calculation.

I can easily believe that.

[zymot]

So many variables in play.Variety of hop used (not all hops behave the same under the same conditions)The crop of said variety (e.g. not all 5% AA Cascade are the same)The age of inventory used (when was it harvested, 1 month ago, 6 months ago?)The provenence of the hop ((how long did it sit in a bale?, freezer, warehouse, vacuum bag, etc?)The kettle time (you think you time it down to the minute, but you don't)Formula used (Ragar, Tinseth, etc)I remember reading about a test that certified beer judges could not identify beers with a difference of 10 IBU.Calculated as 4 IBU off? Any perceived difference will most likely be due to your expectations before actual flavor.