I do partial boil extract recipes and I'm trying to figure out how to make an IPA with a lot of hops. I've read a lot of the other threads on partial boils and maximum IBUs, and I have a good grasp on how high you can go.
I have been playing around with Beersmith, and the IBU calculator is obviously a bit odd. It lets you add hops and never stops increasing the IBUs. I got some good info from this thread:
but without going into a lot of math and averaging Tinseth estimation with other estimations, etc. etc., here's what I was thinking:
What about just adding hops to my Beersmith recipe until it shows 100 IBUs, and then do some easy math those IBUs with the 0 IBUs from the top off water.
For example: 3.5 gal boil with 100 IBUs, 1.5 gal top-off water (0 IBUs) would make a batch with 70 IBUs. (3.5*100 + 1.5*0)/5
Is this close enough, or am I missing something about Beersmith?