Hop Experimentation – An Idea

Thursday, November 17th, 2011

How any IBU’s is too many?

Most craft beers now list the IBU (International Bittering Units) on the side of their bottles. I like hopped up beers – but, really couldn’t tell you my hop preference in an number form. You see, it all depends on the style of beer – some beers seemed too bitter at 60IBUs while Pliny the elder seems balanced at over 200IBUs… Then there is this monster: Alpha-Fornication (2500+)

So, I was thinking that it would be nice to have a horizontal comparison – the same beer, with the same ingredients – but at drastically different IBU levels.

For those playing at home, I guess you could try Dogfish Head’s 60, 90, 120 minute IPA line. Even then, the ABV would be different…


Start with 10 gallons of 5% wort.

  • Add hops every 30 minutes.
  • Pull off 2 gallons
  • Repeat until wort is gone.


This will give us a range of similar beers with exponentially varying levels of hop goodness.

Percieved Issues:

1. Evaporation will cause the wort to get stronger during the long boil.

True, but at least we can use a hydrometer to check this. And we can always dilute post boil to keep them all at 5%.

2. It’s going to be hard to calculate the true IBU’s & I don’t have the equipment to test for the real numbers

True, but I think we can make a fair estimation (see below).

3. It’s going to be hard to boil that last 2 gallons with 10oz of hops

True. That should be interesting.


I put the numbers into a brew calculator. The Tinseth formula was used. For each one, I adjusted the grain level to meet 5% and then added the hops. The hops are Chinook @ 12.5%

Gallons Hop Additions IBUs
10 30 36
8 60, 30 100
6 90, 60, 30 212
4 120, 90, 60, 30 440
2 150, 120, 90, 60, 30 1123

Wait, that’s not right!

For one thing, that shows the numbers for adding all 10oz of hops to the 2 gallon boil. It does not take into account the acids that are pulled off when the other wort is removed!

Gallons Hop Additions IBUs
10 30 36
8 60, 30 93 = 100-(36/5)
6 90, 60, 30 187 = 212-(100/4)
4 120, 90, 60, 30 369 = 440-(212/3)
2 150, 120, 90, 60, 30 903 = 1123-(440/2)

This table isn’t perfect either, but accounts for *some* of the loss. In any case, it shows some huge hop potential!


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