IBU's from whirlpool?

[mitchar19]

How many IBU's can I expect to get from a whirlpool addition? For example cutting off the flame, throwing in my hops and putting the lid on and letting it whirlpool for 20 minutes. Will it be the equivalent of a 20 minute addition?

 

[MalFet]

That depends on your rate of temperature drop. If you're just whirlpooling with no chilling, you won't lose much heat and thus you'll be adding 20 minutes to each of your additions. As temperature drops, though, isomerization drops too. I can't find the article I read off hand, but I believe that isomerization rates drop in half for every 10ºC of temperature you lose.

 

[scottland]

It's kind of like a 20 min addition. I don't have the exact numbers of in front of me, but basically any temp over 170* and you're isomerizing alpha acids. The closer to 212*, and this reaction happens quicker.

So as Malfet said, it depends on how well your kettle retains heat. If the wort stays at 200*+, think of it like a 15-20 minute addition, although with more aroma because there isn't an active, strong boil driving off aromatics.

 

[mitchar19]

So at what temperature would you guys say pro breweries run their whirlpool at?

 

[MalFet]

So at what temperature would you guys say pro breweries run their whirlpool at?

Very close to boiling. It takes a lot of cold to bring those kinds of volumes down to temp.

 

[buckeye2011]

So how much of a difference will there be between a 20 minute addition and 20 minute whirlpool (assuming the whirlpool temp is pretty near boiling)?

 

[NordeastBrewer77]

So how much of a difference will there be between a 20 minute addition and 20 minute whirlpool (assuming the whirlpool temp is pretty near boiling)?

the whirlpool will allow a lot of the aroma compounds to remain in the beer, while still imparting IBU as in a boil. a 20 minute addition will have most of the aroma compounds boiled off, whereas the flameout and steep allows them to remain.