IBUseless

[GuingesRock]

Great! I'm a lot clearer. Thanks.

The hop bill of the IPA I sent you was (10 gal batch):

6OZ Amarillo "skimmed FWH"
5OZ Amarillo 10 mins
4OZ Australian Galaxy hop stand for 30 mins at 175 (won't be doing hop stands in future after your discussion and will carry on cooling, makes more sense)
5OZ Amarillo dry hop (3 days)

= 1lb Amarillo and 4OZ Galaxy

[GuingesRock]

Continuing with the theme of the thread ......

I’ve read several times now that you can’t get over 50 IBUs from a 60 min addition, no matter how large the addition. I noticed it again in here. If that’s true, and I’m not the one to judge that, then it makes nonsense of BeerSmith IBU calculations.

Thermal isomerization of the alpha-acids to iso-alpha-acids occurs via an acyloin-type ring contraction, and the reaction rate is increased with increasing temperatures. Isomerization still occurs at pre-boil temperatures, but the reaction rate at 90° C is approximately half of the reaction rate at 100° C. Isomerization forms two epimers, a trans- and a cis-iso-alpha-acid (forming in a ratio of around 1:3 in wort), meaning 6 different iso-alpha-acids are formed from the 3 major alpha-acids present in hop resin. The trans-isomers are both less bitter in flavor and less stable (i.e. more prone to oxidation) than the cis-isomers, meaning the cis-isomers are usually more desired. Foam-stabilizing properties of the cis-isomer are though slightly weaker compared to the trans-isomer. The iso-alpha-acids have pKa values around 3.0 and have much higher solubility in wort than the non-isomerized alpha-acids (predicted solubility of trans-isohumulone in water 72.5 ppm). This, along with the fact that the flavor threshold of iso-alpha-acids in water is around 6 ppm, explains why the iso-alpha-acids contribute for the majority of the bitterness in beer. The total iso-alpha-acid concentration can reach over 100 ppm in more bitter beers. The limiting factors include the poor solubility of the alpha-acids, the reaction rate of the isomerization, and the reaction rate of the degradation of iso-alpha-acids. Prolonged boil times (over approximately two hours) do not increase the iso-alpha-acid content of the wort, since after this the rate of iso-alpha-acid degradation exceeds that of alpha-acid isomerization, and the iso-alpha-acid starts to decrease. Hence, the maximum amount of bitterness one can get from a 60-minute boil addition (independent of the size of the addition) is approximately 50 IBU (see this Basic Brewing Podcast and report). If one thrives for a higher bitterness, it must be achieved from a combination of hop additions.

Is this plausible, about the 50 IBU max from a 60 min addition, or was it a poorly designed study?

My biggest complaint about all of this, is the discrepancy between perceived bitterness and calculated bitterness. It's the perceived bitterness that's all important.

As an example; for my Garrison entry (10 gal batch), the only hop addition was a 2 minute one and was 6OZ of Australian Galaxy. Two of the judges said it was too bitter for a weizen and the other 2 judges said it was too hoppy for a weizen. Only one judge hinted at astringency and the comment was “slightly astringent/metallic" but not enough that he ticked the astringent box. This was my first time using a single 2 min addition, so I hadn’t had a chance to go by taste. BS calculated the IBUS at 11.3 which is well below the recommended range of 15 – 30 for a weizen. That fits with what X was saying about BS way underestimating IBUs from late additions.

FWIW, I find Beersmith's estimates of IBUS from 15 minutes to FO to be way off on the low side...

[GuingesRock]

I’m trying to make some sense of some of this stuff. There are reports that late additions and steeping additions make no difference to bitterness from some brewers and some brewing software and others find the opposite.

I wonder if it’s possible that a reasonable 60 min boil addition is maxing out IBUs and in that case adding a late or FO addition makes little or no difference to the bitterness because the maximum is reached or approached as a result of the traditional bittering addition. On the other hand a brewer like me who doesn’t do traditional bittering additions, is able to get bitterness from late additions and hop contact with 85C – 98C pre boil wort.

This might explain also why some people find that BS way underestimates bitterness from late additions. The program only applies maybe when a late addition is done in conjunction with a traditional bittering addition.

I’m suggesting that the effects of a traditional bittering addition predominate over any other form of addition as far as bittering is concerned, and the bittering effect of other additions can become minimal, or insignificant, in the presence of a significant traditional bittering addition. On the other hand without that traditional bittering addition, other types of addition can then contribute more substantially to the bitterness of the beer.

[NASH]

I’m trying to make some sense of some of this stuff. There are reports that late additions and steeping additions make no difference to bitterness from some brewers and some brewing software and others find the opposite.

I wonder if it’s possible that a reasonable boil addition is maxing out IBUs and in that case adding a late or FO addition makes little or no difference to the bitterness because the maximum is reached or approached as a result of the traditional bittering addition. On the other hand a brewer like me who doesn’t do traditional bittering additions is able to get bitterness from late additions and hop contact with 85C – 98C pre boil wort.

This might explain also why some people find that BS way underestimates bitterness from late additions. The program only applies maybe when a late addition is done in conjunction with a traditional bittering addition.

I’m suggesting that the effects of a traditional bittering addition predominate over any other form of addition as far as bittering is concerned, and the bittering effect of other additions can become minimal, or insignificant. On the other hand without that traditional bittering addition, other types of addition can then contribute more substantially to the bitterness of the beer.

If one thrives for a higher bitterness, it must be achieved from a combination of hop additions[/b].

Clearly, you've already answered your own question. They've implied you can get 50 IBU from each differently timed addition. None of it matters unless you're being paid the handsome fee to perform such a study. There's tons of beers out there that range from 51 to 120 IBU and everywhere in between, as analyzed in laboratories. Therefore, it's possible.

I for one, don't give a fuck about any of it. There's studies that show eating oranges are bad for humans.

If it held water, it still wouldn't effect my calculations, the way I brew, nor yours. Brewing is an art form and will remain so for a long long time to come, probably forever. You cannot calculate everything. You cannot calculate final flavour or perception which is different for each person anyways. Likewise, nobody can calculate IBUs accurately. It's a guideline.

[GuingesRock]

I for one, don't give a fuck about any of it. ....

If it held water, it still wouldn't effect my calculations, the way I brew, nor yours. Brewing is an art form and will remain so for a long long time to come, probably forever. You cannot calculate everything. You cannot calculate final flavour or perception which is different for each person anyways. Likewise, nobody can calculate IBUs accurately. It's a guideline.

I've nothing more to say. That's actually brilliant.