Whirlpool Hopping

[mppatriots]

Hi, I just wanted to point out what I think is an anomaly in the hopping profiles.  I recently made a recipe where i have a 5 minute addition as well as a 15 minute whirlpool.  Oddly, the 5 minute addition produced less IBUs than the whirlpool.  I'd say that this can't be correct given the fact that the 5 minute addition would continue to increase in IBUs as the hops stay in the kettle for the whirlpool as well. 

Thanks,
Mike

[brewfun]

If your beer is below 50 IBU at knockout, your point is well taken. However, if your above that threshold, there appear to be diminishing returns to the amount of isomerization. 

In general it's true that wort above 90C can and will continue to isomerize AA. However, according to a presentation by Tom Shellhammer of Oregon State, up to 30% of perceived bittering is hop plant polyphenols, not just the actual AA isomers.

Additionally, according to the ASBC, late and whirlpool isomers are highly dependent on the amount of CoHumulone in the hop. Plus, the breakdown of isomers by heat exposure longer than 90 minutes is generally understood and accepted.

As of this posting, there is no research available on whirlpool hop isomerization in worts at or above 50 IBU.

[mppatriots]

brewfun, wouldn't that mean that I would see less IBUs coming from my whirlpool since it is coming after flameout?  At this point brewsmith is showing that it is producing more IBUs than my 5 minute addition.

[brewfun]

Yes. No. Maybe. It depends..... 

It's only been a couple of years since "burst hopping" became trendy, then came the concept of whirlpool hopping. A lot of observations arecoming from respected beer writers and podcasters. There's absolutely nothing wrong with the observations as such.

Trouble begins when the observations become embedded in brewer expectations about what their beer is going to turn out like. Some are observing that the calculations don't go far enough, while others are fretting that they go to far.

There is one certainty: Your beer is still the same as you planned it, no matter what the software says.

Within BeerSmith you can change the whirlpool contribution. Options > Bitterness.

Some things to consider:

• Worts over 1.050 begin to inhibit isomer solubility.
• IBU strengths over 50 IBU diminish solubility.
• BELOW these two criteria, isomerization happens at temperatures above 170F and continues pretty predictably until these levels are reached.
• ABOVE these two criteria, isomerization diminishes until 80 IBU, where isomers begin to be broken at an increasing rate. However, enhanced flavor contribution seems to be the exchange.
• Saturation is maxed out at 100 IBU.
• Bitterness perception is maxed out at 70-80 IBU. An average person can't taste above 60 IBU.
• The TEXTURE of the bitterness (coarseness) is more important in bitterness perception than actual IBUs. 50 IBUs of Chinook tastes far more bitter than 50 IBU of Horizon.
• Hop aroma and flavor drastically change bitterness perception increasing it by as much as 400%.

My advice to any brewer is pay attention to IBU's created with 20 min or longer boil time, after that, consider it mostly flavor, aroma from hop oils, and texture from coHumulone and hop leaf tannins.

The calculations will sort themselves out. You can change them if you wish, too.

Keep Calm and Brew On!