IBU Calculations

I recently brewed an IPA (pictures, recipes, and review of it will come in subsequent posts) and was curious what my IBU's (International Bittering Units) were for this recipe.  There are calculators available online that will do the math for you, but for those analytical homebrewers like myself that enjoy crunching numbers, John Palmer's "How To Brew" website gives a clear understanding of how to determine it.

The basic formulas you will need are:

IBU = (AAU x U x 74.89) / Volume, where AAU is the Alpha Acid Units, U is the Utilization, 74.89 is a constant to convert from ounces per gallon to milligrams per liter, and Volume is the volume of the recipe.

AAU = Ounces x % Alpha Acids

To determine the utilization, you will need to use a table such as the one provided on the "How To Brew" website.

For those who are computer savvy, if you take the time to plug some of these numbers in to excel, you can also create a handy calculator on your own.

After completing these calculations, I was able to determine my IPA IBU's to be 61.  The beer is still conditioning in secondary fermentation right now but will be kegged this weekend and carbonated by the middle of next week.  We'll see how it turns out!