Hops and IBU'S

[kikid]

Hi all
Have a few questions re IBU'S. When a recipe is followed the hop additions may go as follows - 10g at 60 min, 10g at 15min - all pretty straight forward. The calculator estimates the total IBU'S. If I then add hops at flameout as whirlpool the calculator gives these hops a value say 10%. Can I assume that the calculator takes into account that the pre flameout hops have been in the wort for say 80min and 35min accordingly?
Robert

 

[Head First]

Hi all
Have a few questions re IBU'S. When a recipe is followed the hop additions may go as follows - 10g at 60 min, 10g at 15min - all pretty straight forward. The calculator estimates the total IBU'S. If I then add hops at flameout as whirlpool the calculator gives these hops a value say 10%. Can I assume that the calculator takes into account that the pre flameout hops have been in the wort for say 80min and 35min accordingly?
Robert

Good question. Just guessing but I would think the difference would only be a small amount. Not enough to taste the difference at a homebrewing level. Just an educated guess though.

 

[Nosybear]

There's not much hop utilization past the first 45 minutes. IBUs are an estimate only - we're not measuring mg/l of Iso Alpha Acid! Short answer, no. Longer, perhaps more useful answer, if it's a concern, just put the hops in 20 minutes later, then you'll be back on schedule! I've never taken the previous hop charges into account when whirlpooling, just adjust the hop charges for the next recipe.

 

[Beer_Pirate]

I've started adding hop charges separately to the whirlpool list if they've been added later than the 20 minute mark. For example, I don't worry about a 60 minute addition, but if I add 14g at 5 min, then whirlpool for 20, I add the 14g again as a 20 min whirlpool. I do it just because I assume the calculator doesn't. This way I can get consistent bitterness if I'm adding a high AA hop like citra or sorachi ace late in the boil, then use something super low like medusa in a similar recipe. YMMV.

But, as others have stated, the calculator is just a guess as to what the actual IBU of your beer will be. Find something that tastes good to you, and note where that IBU falls on the recipe builder. There are many other factors to consider when talking about perceived bitterness of a beer (water chemistry is a never ending rabbit hole). As always, RDWHAHB.