Challenger440

Recipes 

Hey guys
I'm trying to convert a simple hop schedule to hit the desired IBU mark. The hops my LHBS carries are 4.5% and the recipe I am going from used 5.0%.

The recipe adds 1.0 oz Kent Goldings (5.0%) at 60 minutes, for 17.2 IBU. How many ounces of Goldings do I need to add at 60 minutes to hit 17.2 IBU?

Recipe: 1.0oz (5.0%) 60 min = 17.2 IBU
Me: ???oz (4.5%) 60 min = 17.2 IBU

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Primary #1: Edwort's Apfelwein
Primary #2: Stout
Primary #3: Edwort's Pale Ale (all late hops)
Kegged: Moose Drool, Edwort's Haus Pale Ale
Bottled:Oaked Stout, Tequila Cider, Stout
On Deck: Hef, Oatmeal Stout, ESB

humann_brewing

Recipes 

Here is the equation.

IBU = [W(oz)*AA%*U*7489]/V(gal)

the answer would be 1.02

IBU = [1.02*0.045*0.25*7489]/5

You can see by this that it doesn't matter much as I have found in brewing, ballpark is close.

A4J

Recipes 

It's monday morning and maybe the answer is obvious, but what does U represent?

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Primary: altbier
Tap 1: pale ale
Tap 2: hibiscus kolsch
Tap 3: traditional kolsch
Tap 4: moose drool clone
Tap 5: soda
Bottles: porter, raspberry ale, and a lot of commercial microbrews
planning:flanders red or oud bruin

My Mid-Century Modern Inspired Keezer Build

humann_brewing

Recipes 

U is the time, .25 is for 60 minutes. Here is the article.

http://www.byo.com/stories/recipes/article/indices/50-recipe-calculations/412-calculating-gravity-bitterness-and-color-techniques

A4J

Recipes 

utilization [time]. That's what I figured.

grassy-ass.

__________________
Primary: altbier
Tap 1: pale ale
Tap 2: hibiscus kolsch
Tap 3: traditional kolsch
Tap 4: moose drool clone
Tap 5: soda
Bottles: porter, raspberry ale, and a lot of commercial microbrews
planning:flanders red or oud bruin

My Mid-Century Modern Inspired Keezer Build

homebrewer_99

Recipes 

Divide 5 by 4.5 = 1.1 oz.

__________________
HB Bill

Challenger440

Recipes 

Thanks guys!

__________________
Primary #1: Edwort's Apfelwein
Primary #2: Stout
Primary #3: Edwort's Pale Ale (all late hops)
Kegged: Moose Drool, Edwort's Haus Pale Ale
Bottled:Oaked Stout, Tequila Cider, Stout
On Deck: Hef, Oatmeal Stout, ESB