How does adjustments to boil affect hops additions?

halfbrew70 said:

I'm curious about how adjustments to the boil time affect hops additions.

For an example, lets say that my schedule is:

60 minutes bittering
15 minutes flavoring
5 minutes aroma

1. What if I realize that my boil off is too slow or too fast and that I need to extend or decrease the boil time? How does that affect the bittering hops? Does more boil time increase the bittering?

2. If I extend the boil time after adding the flavoring hops, does it increase the hops taste?

3. If I extend the boil time after adding the aroma hops, does it just boil off the affect of those hops and result in a decrease in the aroma?

Thanks!

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rhamilton said:

#1. For bittering hops you get diminishing returns on boil time. So for every minute after 60, you'll get fewer and fewer IBU's per extra minute of boil. But to answer your #1 question, yes, longer boil = more hop utilization.

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rhamilton said:

#2. No. You'll get more bitterness from the flavor addition, and less flavor.

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halfbrew70 said:

So the hops "efficiency" diminishes over the boil, but I would still end up with higher IBU's overall, right?

Also, maybe I should confirm, are IBU's and bittering the same thing?

You also said that "longer boil = more hop utilization". More utilization equals more IBU's, right?

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rhamilton said:

Efficiency (AKA utilization) for hops always increases as you boil longer. The diminishing returns bit means if you boil for 120 minutes, it doesn't mean your IBU will double vs a 60 minute boil. You will squeeze a little more IBU out of the hops, but by 60 minutes, you've already extracted a vast majority of the bittering potential. As an example:

1oz of 15% AA hops, boiled for 60 minutes, yields 89 IBU for a 5 gallon batch. Extend the boil to 90 minutes and you get 96 IBU (+7 IBU), or extend the boil to 120 minutes and you only get 98 IBU (only +2).

Yes, IBU is a unit of measurement for bitterness. You'll notice bittering additions contribute most of the IBU. Flavor adds a little IBU. Aroma adds almost no IBU. But as you boil the flavor and aroma additions longer, they will contribute more IBU and less flavor/aroma.

Yes, more utilization means more IBU. The longer the boil, the more IBU the hop additions will contribute, but keep in mind the diminishing returns.

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TopherM said:

You are really focusing on the wrong thing with this question. You are trying to manipulate the wrong variables.

Instead of worrying about how the hop/bitterness variable changes when you can't control your boil, you should focus on making your boil a constant, controllable variable, which is pretty simple.

Your pot has a set boiloff rate at a vigorous boil that is a factor of the diameter of the pot. You should always boil as vigorously as you can without boilover, so as long as you are using the same pot and the same burner, that is a set variable.

Always boil one click below boilover, and now your hop utilization and boil off rate are both constant variables, and THE NAME OF THE GAME in good brewing is controlling as many variables as possible.

Now that boiloff and hops utilization are a constant variable, now you can simply control when your hops additions are as the manipulative variable, and it's simply the longer they boil, the more bitterness and IBUs they add to the beer, the shorter time they boil, the more they add to aroma (and add almost nothing to IBUs), and anything in the middle part of the boil add a hybrid of bitterness and aroma, which is FLAVOR!

Good luck!

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Can you boil off too quickly? I suppose that if the aim is to boil as vigorously as I can, I'd simply adjust the beginning level to allow for my boil off rate (once I know it)?

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TopherM said:

You're exactly on....the aim is to boil as vigorously as you can

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