Originally Posted by freakish
i guess what it comes down to is can i make a 2.5 gallon wort 200 ibu's then dilute with 2.5 water to make it 100 ibu... but it sounds like i cant since it doesnt matter how MUCH water you start with, water cannot be more bitter than 100ibu-bitter.
There have been other threads on this matter, and I think the jury is still out. The last I could remember, is that there are some examples where wort can hold a lot more than 100 IBUs, but fermented beer seems to limit the amount of IBUs to some where in the region of 100. If that is the case, you may be able to brew a 5 gallon 100 IBU beer with a 2.5 gallon boil.
I know I'm not really answering the question, but until someone shows me that wort limits the IBUs to around 100, I'm going to continue to believe the beer calculators.