Hop IBU Formula

[Rob Martin]

Last meeting there was some discussion on which Hop IBU Formula to use.

Can someone provide a commentary on Rager vs. Garetz vs. Tinseth?

What would you recommend I use? I brew on a 10-11 gal all-grain system using a full boil.

Thanks.

[Joe Yoder]

I use the Rager method, just because it seems more local to me. Doesn't really matter though as far as I can tell, just pick one and stick with it and let your taste buds be your guide.
Joe

[Jdl973]

I use the ...sniff...oh that smells good...grab handful...dump in boiling pot...repeat...method.

[DJ in KC]

Here you go

http://users.rcn.com/thor.dnai/dboard/d ... t9509d.htm

I use whatever Tastybrew uses - IIRC it's Tinseth. Yeah, still too lazy to buy and set up Promash.

FWIW there was a podcast a while back with John Palmer talking about a conference he went to. It seems that the amount of hot break rather than gravity is what influences hop utilization.

[Jdl973]

With all these formulas, your are just getting in the "ballpark"

The only bittering capability in the final beer is produced by the Isomerzatoin of the alpha acids (humulone, cohumolone and adhumulone) to change their chemical structures into iso-alpha acids, which accounts for a very small portion of the total alpha acids present in the hops. Beta acids, lupulone, colupulon and adlupulone, will also form iso compounds in very small quantities and do not contribute to the beer's final bitterness.

The chemical change of the alpha acids can be effected by hot break, cold break, the pH, the time of boil, the intensity of the boil, the concentration of the initial acid in the hops, the age of the hops (oxidation reduction reaction), atmospheric pressure, final wort volume, wort gravity and on and on. The only true way to test the final iso-alpha in your beer is to test it with a gas chromatorgraphy mass spectrometry (I am still trying to get my hands on a used one for the basement... ) which is what the "big boys" do on each batch. Even the huge brewers can not get the final IBU consistent from batch to batch and will blend several batches to even out the inconsistencies and produce a similar IBU profile from bottling to bottling.

In the literature, it seams to me, the two biggest factors is your brewing procedural consistency and the boil time. Whole hop utilization ranges from approximately 15% at 30 min to 24% at 60-74 min and 27% longer then 74 min. Changes to your brewing conditions, volumes, vigor of the boil, size and shape of the boil vessel ..., can also effect the utilization.

The human pallet, on average has a sensitive threshold of approximately 5 IBUs. That is you can not taste the different in the bitterness in a beer + or - 5 IBU. So in essence there is a 10 IBU spread on the perceived bitterness in any beer you make.

So the take home point is, all the calculations for a home brewer are approximate. They will get you in a "ball park" range of bitterness of your final beer. Keep your process consistent from batch to batch, take good notes, have a sufficient boil time and your beer will be fine.

A real good reference is Designing Great Beers by Ray Daniels, page 72-90. I think we have this in the club library, it not I would highly recommend it...great book.

Personally, I use Beer Smith to get me in the ballpark, take good notes on each brew and adjust fire from there.

Just my $0.02

Jason

[Jensen]

Like Jamil, l I have always used Rager, and like Jamil, I have always used Promash. I have taken 3 different courses on home brewing early on in my brewing career from Jackie Rager. He was also very instrumental in the early formulations of Freestate's beers, of which he is an original investor. Any formula is a ballpark indeed. You adapt it to your particular system, and your particular brewing techniques. I too, like to keep it local. If you have a question about the formula-- the man if only 30 miles away, and loves to talk home brew.

[Rob Martin]

My Promash default is Rager. As some of you are aware, I am not a hop head by any means, but I've noticed that to me, the bitterness does seem a bit low compared to the range that I'm selecting within a particular guideline for a style. If I try to get a mid-IBU and set my hop schedule accordingly, to me it comes out more on the low end. If I set it on the high end (generally for a low hop style), it seems to come out more in the middle.

Reading the article that Dan posted was interesting. I also searched for a few others.

It seems that the consensus is, 'whatever you are using, stick with it'. Why would you recommend not switching from Rager to say, Tinseth?

I'm leaning towards switching to Tinseth. There may be a learning curve in the short run as my beers may seem to be hoppier than what I'm accustomed to, but even as a homebrewer that prefers either balanced or even malt-forward beers, I admit some of my beers could use more hops. Additionally, sometimes on my 5 gal system, I wouldn't be able to do a complete boil, but with the 10 gal system, we always do a complete boil, so the Tinseth calulations seem to be more in line.

Comments?

[brick]

Here is the way the formulas work out for an identical hop build in a beer: Rager will calculate the highest IBU, Garetz the lowest. with Tinesth in between them. What does this really mean? If you make a beer and use the formulas to calculate 50 IBUS - Garetz will actually be the most bitter and Rager the least.

[Blktre]

I'm also a Rager brewer. Works for my buds...