theory shmeory.
No chilled beers are measurably more bitter than beers which are not no-chilled. I know, I have in fact measured the difference. Enough measurements to be statistically significant for the fussy science types out there, iso octane extractions if you care.
I made graphs and tables and all that shit.... dont ask, they are all gone in the great hard drive crash of years past. However, I have retained the useful result.... the useful result being that if you take a recipe and you look at your hop additions - the difference that will be made by no-chilling the beer is the same as you would get if you made your last hop addition and at the time you were meant to turn off your kettle... you forgot and left it run for an extra 10-15 minutes (ignoring volume changes) - then chilled it. Fast with an immersion chiller.
That was all worked out using Pro-mash and the Rager ibu formula, which is what I use. Basically i just plugged in numbers till things worked out. So wort A ended up say 5% more bitter in the NC version vs the Chilled version, so i plug the recipe into pro-mash and click the boil time up till the IBUs have gone up by 5%. Repeat for all samples. Work out a range and call it as good a guess as any.
Turns out its 10-15 mins. If you happen to shove an amount of hop pellets (loose) into your actual cube and not boil them at all, that'll add bitterness as though you had boiled them for 20-30mins.
You want to "compensate" for no chill but use software that assumes you do chill? - calculate your bitterness as though you were going to make all your additions 10-15 minutes earlier in the boil (including your bittering charge) and then simply reduce the bittering charge till your expected IBUs match the recipe. DONT actually change when you add the hops. Not that hard really.
And sweeties.... thats just about as close as you are ever going to get. I used to chill with an immersion chiller and swapped to a plate chiller... all my hops sat in a kettle full of very hot wort for 20-30 minutes longer than they used to. would that have changed my bitterness?? Of course it would. Does the brewing software take it into account? Hell no, but you dont see ******* thread after thread on AHB about how people cant calculate their bitterness properly anymore because they bought a plate chiller.
How about the different IBU calculators that DO assume you chill? Try going into the settings of your software and changing from Rager to Tinseth, or Daniels, or "generic" and see what that does to the expected IBUs over a few different recipes. Or how about FWH?... my software defaults to FWH reducing IBU levels significantly vs a normal boil, other software defaults to it increasing IBU levels?? Oh - and how many of you take note of the date your hops were picked, then plug their proper age & the type of material they were stored in & the temperature they were stored at, into your software to estimate their degredation in IBU potential during storage. And what effect did the repackaging and storage conditions that happened at the HB shop before you even bought them have? Do you compensate for potential between hop flowers and hop pellets? - what about type 90 pellets vs Type 45 pellets and each of those vs flowers? What about different varieties of flowers whose cones have different physical structures which will affect the way that the hops resins are able to be physically dissolved in the boil? what about the vigor of your boil? What about the difference in utilisation potential between dark and light worts with different pH levels? hmmm? I could keep on going for a while too.....
What I'm kind of unsubtly trying to get accross, is that ALL the hop formulas are just a moderately educated guess - and none of them are very accurate at all (able to measure remember). They ALL require you to stick with them and not change your technique, over a few brews and feedback the way the beer tastes into your recipe development. Adding a 10-15min "No-Chill Factor" into the mix is barely even going to make a ripple in the lake of mixed bullshit and guesswork that makes up Homebrew IBU calculations.
Brew your beers the way the recipe says.... if you notice that your No-Chill beers (or all your beers if you only no-chill) are always a little more bitter than you'd like. Reduce the bitterness you add! Its that simple. If by chance you'd like a hint on how much to reduce it - well then, a good place to start is to calculate the bitterness in your no-chill beer, as though you'd boiled all your hops for 10-15min longer than you actually plan to. the increase in bitterness you get is how much you should reduce your bittering addition by.
See how it works out - tweak as required to suit your brewery - sorted.
TB
