Hop bitterness calculations

Since there has to be a first post some time, I thought I’d start. I need a break from coding, too.

All hop utilization formulas are “best fit” calculations to enpirical data – researchers look at results from their expirements and try to find an equation that best fits the data. This reality produces a few different ways to estimate the final bitterness in your beer. For BrewSession Greg and I decided to offer three bittering calculation methods.

Many brewers regard Tinseth’s method to be well suited when doing full boils using whole or plug hops. There are quite a few parts to it, all of which we will post to the FAQ or User’s Guide or Glossary when we get it up.

Partial-mashers and extract brewers are better served by Rager’s method which is more accurate when doing partial boils with pellet hops loose in the boil. We’ll make this formula available too.

Daniels-Mosher is a somewhat new formula. In fact, I can’t find the formula referenced on the Internet (speak up, Greg). We will be sure to include it with the others.

Because we want to use the right tool for the right job, I devised some programatic logic to select a utilization calculation that best fits the hop as used in individual recipe bitterness calculations. Currently there is no regard for full v. partial boils, only hop form – all the information is there, so the code may change if there is a need. The code first checks to see if the user has a preferred calculation method and uses that if present. Failing that, BrewSession decides which method is better – Tinseth for whole and plug hops and Rager for pellets. If BrewSession can not figure out the hop’s form, it uses Daniels-Mosher. Unsure of where to best use D-M, I threw it as the “unknown” case. If you have ideas, hit the comments or drop me an email.


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