Anyone have a 'dilution tool' for IBUs? Affect on IBUs with a big starter?

[beowulf]

I'm brewing an IPA today ~1.075, and worked up a 3L starter over the last few days. I refuse to underpitch! Yeah, maybe my some accounts it's excessive....but better to have it and not need it...you know where I'm going with this...

Anyway, I originally intended to cold crash so that I didn't have so much starter to pitch, but the starter is currently at high kraeusen or thereabouts. I don't really want to interrupt it's progress....although I'm not sure how much yeast growth I'd miss out on if I stuck it in the fridge now. It'll probably be about 6 hours before I pitch.

I don't really have a problem with this, even considering the dilution factor. So, I can adjust my grain bill up since I haven't mashed yet. The question I have has to do with calculating IBUs. I'm assuming I should boost them a bit to make up for the added liquid in the starter, but how much? This is for a 5 gallon batch. Anyone know of a "dilution tool" for IBUs like the one for wort that's in Beersmith?

 

[JuanMoore]

I would think that increasing the batch size volume in Beersmith would get you close enough. I don't know of any IBU dilution tools or formulas.

 

[beowulf]

Yeah...I tried that, and it only went down maybe 5-10 IBUs. Should be close enough. The difference is that the starter wort is not part of the boil, so it wouldn't be subject to the bittering hops.