[gradys]

Hi,
If you are going to formulate NEIPA recipe with a lot of first wort hop additions and even more whirlpool hop additions I believe you will get stuck on final IBU estimation.

In this case you might want to check this new Diversity Methodology developed by Petr Novotný (Zymurgy Contributor by the way).

Part one, part two, part three and finally the most important part four (so far in Czech only - maybe Petr will publish new article in Zymurgy about this methodology?  ).

But you don't have to study the math nor create your own application. If you want to try the new model, you can do it online here: https://www.homebrewmap.com/en/tools/calculators/ibu-diversity

[hopfenundmalz]

Very interesting, thanks for posting.

[gradys]

I still don't have any "hard data" confirming the model functionality, but I've used it couple of times (NEIPA, IPA with LOT of late hop, ...) already and my "subjective bitterness perception" in resulting beers tells me it might work 

[gradys]

Diversity Methodology is now available in English in latest ZYMURGY issue (Vol 41, March/April 2018, pg.38, Revisiting the IBU by Petr Novotný)

[Petr]

Saving to check out later.

I really hate the way BeerSmith and BrewersFriend handles whirlpool additions, but without an english publication it'll be hard for me to trust this guy. Especially considering his refractometer correction formula

It was published in a new issue of Zumurgy, so now you can read it in English. I'm the guy. What is the problem with my refractometer correction? It works great for everyone so far, much better than Terrils's one and giving the same numbers as BeerSmith's tool...

[dmtaylor]

Saving to check out later.

I really hate the way BeerSmith and BrewersFriend handles whirlpool additions, but without an english publication it'll be hard for me to trust this guy. Especially considering his refractometer correction formula

It was published in a new issue of Zumurgy, so now you can read it in English. I'm the guy. What is the problem with my refractometer correction? It works great for everyone so far, much better than Terrils's one and giving the same numbers as BeerSmith's tool...

I for one have been impressed by your refractometer calculator.  Very accurate compared with hydrometer, for many different styles of beer with differing attenuations.  Thank you sincerely.

As for IBU calculations... this topic is not as interesting to me personally but I do hope others will find it useful.

[hopfenundmalz]

I liked the Zymurgy article!

[Robert]

Me too.  Not enough attention has previously been drawn to the issues of degradation and loss of bitterness with longer boils/increased thermal loading. One more reason shorter/less intensive than conventional boils will certainly not harm our beer.

[mabrungard]

I was already aware of the degradation of iso-alpha through Malowicki's work, but I was pleased to see the additional reference in that article from the IBD journal that confirms it. My upcoming article on Wort Boiling covers that degradation.

As Robert says, boiling too hard or too long has some serious negative effects on beer. 

[Petr]

I was already aware of the degradation of iso-alpha through Malowicki's work, but I was pleased to see the additional reference in that article from the IBD journal that confirms it. My upcoming article on Wort Boiling covers that degradation.

As Robert says, boiling too hard or too long has some serious negative effects on beer.

Malowicki and Shellhammer did a great deal of work on that! Good for us.