**EDIT: As will sometimes happen, I posted this, and with more poking around found the answers I was looking for. Disregard this post.**
I will soon be brewing my second batch of beer, and this time I'll be going for an IPA. I was using http://beercalculus.hopville.com/ to help assist me in tweaking a recipe to make sure I was hitting my numbers for the style I was brewing. I'm doing a stovetop extract/steep, so I won't be doing a full 5 gallon boil, more like a 2-3 gallons and topping off the carboy with water. I noticed, though, that when I adjusted the size of my boil, it seemed to significantly affect the final IBUs. I get a 15 IBU swing between a 2 and a 3 gallon boil, (from the low 50s-high 60s.) Is this correct? Have I "saturated" the 2 gallon batch with hops, thus wasting leftover potential acids? I can't think of another reason why adding more water would yield more IBUs.
I will soon be brewing my second batch of beer, and this time I'll be going for an IPA. I was using http://beercalculus.hopville.com/ to help assist me in tweaking a recipe to make sure I was hitting my numbers for the style I was brewing. I'm doing a stovetop extract/steep, so I won't be doing a full 5 gallon boil, more like a 2-3 gallons and topping off the carboy with water. I noticed, though, that when I adjusted the size of my boil, it seemed to significantly affect the final IBUs. I get a 15 IBU swing between a 2 and a 3 gallon boil, (from the low 50s-high 60s.) Is this correct? Have I "saturated" the 2 gallon batch with hops, thus wasting leftover potential acids? I can't think of another reason why adding more water would yield more IBUs.