IBUs - Let's get this sorted out.

It's certainly why I hang around. I wouldn't know diddly about brewing and a lot of other stuff without people like you to learn from.

 

I think bitterness ratio (BU:GU) is way more helpful. Brewers surely have the info, but probably just don't post it on their cans because it's not as sexy as IBU's (which are usually only posted on hop-forward beers).

 

Right. But the majority of the world will say that a teaspoon of sugar is sweet. That a lemon is sour. That a banana tastes like a banana and not a lobster. To me, this means that the the majority of the population perceives tastes in a similar way.

How would a restaurant operate if everone tasted things as differently as your post indicates? There is enough commonality in tastes for them to exist

 

IBUs denote parts per million of isomerized alpha acids. They are of no use to you unless you make beer. Even if you do make beer the concept is of little use unless you have access to expensive lab equipment and the training to use it. Most small breweries and almost all homebrewers do not. If you don't have these things all you can do is calculate IBUs using one of a range of ludicrously inaccurate formulas which will give you a number that is probably in no way representative of the actual bitterness of you beer (this is how we get numbers like 120IBU, 1000IBU, etc when somewhere around 100 is the actual physical upper limit).

The only people who should be talking about IBUs are people with serious chemistry labs and entry level beer geeks who want to sound like they know what theyre talking about when they absolutely do not.

 

It's exactly how IBU's are measured or calculated which interests me. As a person who is a serious analytical chemist, I'm curious what methodology and equipment is used to measure and quantify IBU's. I'm going to assume this is done chromatographically but I'd like to know a few more specifics.

 

I'm curious why I've heard ibus can't actually be higher than 100. Why not?

 

For further research (all you beer geeks), try

http://homebrewmanual.com/what-are-ibus/

All this talk about IBU's has made me crave an Imperial IPA - cheers!

 

It's claimed that human perception only goes up to about 100, such that we can't taste the difference between 100 and 1000.

 

I'm not a chemist, but my understanding is that it can be measured with a UV spectrophotometer. Not a hugely expensive piece of equipment, but something 95% of craft breweries aren't going to have.

There is some more detail in the last post on this thread: http://discussions.probrewer.com/sh...meter-amp-microscope&highlight=ibu+microscope though you would probably have to join the ASBC (american society of brewing chemists) to get a detailed methodology.

 

Most people can only taste around 80-100, and the solubility limit in wort is something like 90-110, any more that that will just precipitate out.

 

Following that logic I guess we should leave IBUs to chemists only and government to politicians only and drinking beer to beer drinking professionals only.

 

At a recent talk, a brewer said at festivals the following progression happened in questions they would get over the years.

"What is your thickest, darkest beer?"
"What is your highest ABV beer?"
"What beer has the highest IBU level?"

He then laughed.

 

I got the question at bar trivia a couple weeks ago, what does IBU measure?

I wrote "alpha acid concentration/bitterness" knowing the correct answer was "Bitterness", but part of me was tempted to just put the real correct answer so I could explain to the trivia jockey after that my answer was actually correct.

 

I don't know why he laughed. Was it because they were silly questions? Or was it to show how people used to be interested in dark beers, and then high alcohol percentage beers, and now very hoppy beers? If the latter, I fail to see why that is funny (not faulting you hopfenunmaltz, but the brewer who laughed). Would it be funny if someone asks next year what the most sessionable beer is or what barrel aging program they might get involved with?

 

Someone on here had the idea of using a slider (on a "bitterness scale" and others) for reviews. That would be kinda cool.

 

You are pretty close but your not being very nice. The reason it is difficult to estimate IBUs is because the formulas are based on a utilization factor. Theoretically speaking the highest amount of alpha acids that could be utilized (isomerized) is somewhere in the 30-40% range assuming you boiled the hops for 75 plus minutes. However there are many other variables such as the gravity of the beer, the volume of the beer, the brewers system and the quality/variety/age/method of introduction of the hops. The formulas are not inaccurate there are just many variables and varying opinions regarding the utilization continuum. The actual levels can be analyzed in a laboratory by people smarter than me. What compounds this are the modern practices of late kettle hop additions/hop stands/dry hopping etc. and to my knowledge it is relatively unknown how much bitterness these practices actually contribute. I also don't think that you can definitively say that 100 is the physical limit. Some brewers may use their calculations as a marketing ploy, but that is hardly as ridiculous as some of AB/MC's tactics. I'm just a brewer not a scientist so that is my best explanation. Most of us try to use IBU's to give our customers an idea of what they are buying just like gravity, abv and perhaps a list of ingredients. Cheers.

 

He had been talking about his IPA, which is more balanced than most and not really high in IBUs. It is 70% of his production. They make a lot of it.

He was also illustrating how the trends have changed over the years, and he has been brewing for a long time.

 

I'd guess he laughed because all three questions were asking about extremes. Darkest, strongest, most bitter. I can also certainly relate to those that asked the questions- it's the American way "If some is good, more is probably better"

 

I just remove the labels from my beers so I dont get confused by the numbers and letters and I can just enjoy the beer.