Changing Boil Volume

[TheJadedDog]

I have never played around with boil volume before, but my understanding is that if I increase the boil volume, I have to decrease the amount of hops in order to reach the same IBUs. Is this correct? Are there any negative repercussions?

For example, I have a recipe that calls for a 1.5gal boil. I want to increase this to 3gal, so can I just drop the amount of bittering hops? Or do I need to adjust my aroma hops too? Note, I am using ProMash for all my formulations.

Any and all thoughts are appreciated.

 

[david_42]

Adjust only the bittering hops, unless the aroma hops is a large add of high AA hops. An ounce of Chinook at 30 would need to be reduced slightly. A half ounce of EKG at 20 wouldn't matter. A good rule of thumb is a 10% IBU change can be ignored.