Estimating Hop Bitterness

posted Oct 2, 2012, 11:09 AM by Richard Bryant

By: Ron Unz



When composing your own recipes, it’s often important to know the amount of bitterness the hops you plan on using will impart on your brew. If you want build your own spreadsheets or do the calculations yourself, it’s important to have an idea on how to calculate the amount of bitterness in your beer. The standard unit for bitterness is called the international bitterness unit (IBU). The kind of hops and how long you boil them will determine the amount of bitterness in the final product. The following equation (Glenn Tensith’s equation) can be used to calculate the amount of bitterness in IBUs.

U is the amount of hop utilization, A is the percent of alpha acids in the hops, W is the amount of hops in ounces, and V is the final volume of the wort.

The hop utilization is a function of initial wort gravity and time of your hop additions. The hop utilization is described by the following equation:


 
G is the gravity of the wort (in specific gravity) and t is the amount of time (in minutes) the hops are boiled. It’s important to note that using these equations can only be used for estimating the amount of bitterness in your beer. Utilization values can often looked up in tables if you didn’t want to use this big ugly equation. If you would like to know more about how these equations were derived, I highly recommend that you read through Glenn Tensith’s website (http://realbeer.com/hops/). His website also contains utilization tables and methods to tweak the utilization equation to fit your brewery. 
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