IBU readings in calculators

[laxation]

I've been giving it a go to use some of the calculators available to make some recipes, but it seems each one gives me a different IBU - even when I'm punching in the same custom AA% for hops.

Doing extract, with a 10L boil, can anyone tell me what to look for to get the right IBU?

Apparently it's something to do with hop utilisation or something and boil size but it all gets a bit sciency for me to understand

I've got beersmith 2 on my phone and the spreadsheet from the Kit & Kilo forum, so figuring it out between them would be ideal.

 

[MHB]

You cant calculate the IBU's accurately, the best you will get is a general idea, but really that will be close enough.
If you were making an ESB and the recipe called for 30 IBU, whether in fact you got 20 or 40 it probably wont matter, just fine tune the recipe next time you brew it.
Choose one calculator that you find convenient and use it - knowing the answer isn't exact but that it will do!.
For Your reading pleasure The HBD Palexperiment Results
Mark

 

[technobabble66]

^^ +1. It's very much an empirical thing, especially as everyone sensitivity to & sensory/flavour perception of bitterness is highly varied. So it takes a few goes at repeating recipes, or at least similar recipes, to get an idea of what works best for you, on your system, with a particular style.

TLDR: You need to brew moar!!

 

[laxation]

TLDR: You need to brew moar!!

Agreed! Refreshing the forum all day at work gets me through it, but unfortunately doesn't make my beer ferment any quicker

 

[RdeVjun]

+1 to other replies above. You can cut yourself to pieces on recipators or just take a stab at brewing it, then adapt subsequent batches to your liking. You'll get more familiar with your application's bitterness idiosyncrasies with continued use, they're much of a muchness IMO so which ever one you're comfortable with would be my recommendation.