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When substituting hops (both varieties and pellet/plug/whole)in a recipe, I would like to keep IBU as close to the recipe target as possible. However, the best utilization chart I can find is in "Designing Great Beers" (Ray Daniels) and it requires you to know the 60 minute boil utilization of your hop variety.

Is anyone aware of a resource that provides either these 60 minute boil utilizations or enough information to complete the IBU calculation?

Also, how much variance is there in utilization for a particular variety. Obviously, the AA can be quite different for the same hop, but I am interested in how consistent utilization during boil is (for an arbitrary amount of time in boil.)

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up vote 2 down vote accepted

This is a tough one to get right as there are a few formulas for calculating IBU's. This site includes a description of the two main ones and an online calculator you can use to get the numbers you need.

Note that none of the formulas are perfect and will give different IBU readings. It's important to choose one and adjust to taste from there.

Regarding variance for a given variety from what I've read there shouldn't be much and if there is it's likely to be hard to find out or calculate. Trial and error may be your best option.

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I definately agree with the advice to pick one and stick with it. What's most important is knowing what a 30 in your formula tastes like that you can adjust accordingly. – sgwill Nov 9 '10 at 13:13
Downvoted because there was no explanation that the original question was off base with the theory of utilization. – Denny Conn Feb 23 '11 at 21:52

I like the IBU calculator in Beersmith. Available at www.beersmith.com. the trail version will let you use it for 14 days, and the whole program is only $19.99. It lets you change hop types and times and automatically calculates your IBUS based on those choices. It also calculates for boil size.

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I bought BeerSmith, it is definitely a very nice program! – Mike S Feb 24 '11 at 4:22

The easiest way to figure hop substitutions is the use the Homebrew Bittering Units calculation. simply multiply the hops AA by the amount called for. For example, 1 oz. of 8% AA hops equals .5 oz. of 16% AA hops. There's no need to involve utilization at all.

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