I may be reading too far into this, and this wont answer the original question, but is still on topic for discussion purposes...
Should flame out hops be calculated as the time in contact with the liquid over the isomerisation temperature of ~80*C or time before chilling?
For example:
- If i cut the power and add say 100g of hops at flame out, citra @12% for instance, then begin chilling with my immersion chiller, i get the wort temp down to 80*C in 5 min (from flame out). So if i add a 5 min addition of whirlpool/steep hops into Beersmith, I get 12IBU from this 100g.
- If i were to cut the power, add the hops, steep for 5 min, then start chilling, the hops are in contact with liquid over 80 for 10 min. This yields a calculated 21.9IBU based on a 10 min steep addition.
Any idea which of the two Brad Smith uses when he wrote Beersmith?
For relatively low quantities of whirlpool hopping the difference is negligible to my palate/mind.
However if you rely significantly on late/whirlpool hopping for beers like IPA or PA, then this could make a significant difference to the overall calculated IBUs.
I have only brewed maybe a dozen AG batches, and never the same batch twice, so cannot comment from experience. Has anyone got much practical/theoretical experience in this?
My thoughts would be that Beersmith would calculate the IBUs gained from your whirlpool addition based on time until the wort drops below ~80*C.
If you haven't already, I strongly suggest everyone who is interested in utilisation during chilling/whirpooling have a read of Relaxedbrewer's thread here:
http://aussiehomebrewer.com/topic/81226-calculation-of-ibu-additions-after-flame-out-no-chillwhirlpool/page-2
Post 28 has the more up to date version of the report.
Using this methodology as a guide, you could work out your utilisation for both whirlpool additions and during chilling (Ideal for nochill additions)
I think it would be great if there were two more options in Beersmith (like there aren't enough already!) available.
- Where you add your boil time, (which is selected by default from your equipment profile) you also have a whirlpool/hopstand time which is the time between flame out and when you begin chilling.
- The additions you make as whirlpool additions are treated as time from the commencement of chilling, ie, based on a whirlpool/hopstand time of 30min...
a 0 min whirlpool addition would be at the commencement of chilling,
- a 10 min addition would be 20min after flame out
- a 30 min addition would be 30 min before chilling (flame out).
- The calculated IBUs would be based on whirlpool time and of the utilization factor calculated.
- Utilisation would be dependent on temperature drop over the whirlpool time.
- Hop additions added during the boil will also be altered (increased IBU) due to this whirlpool time, as they will still be above the isomerisation temp (it frustrates me that a 4 min boil addition yields less IBUs than a 10 min Whirlpool addition, as the 4 min boil addition will inevitably be in the whirlpool too)!
- Chilling profiles - This would be where you could enter data on how long it takes you to chill your wort below 80*C. Just like the duration of your whirlpool, you will get increased bitterness from hops if you have a longer chilling time eg nochilling. The temperature drop required - and hence the time, would depend on the temperature drop you got during your whirlpool/hop stand, (which could be negligible based on your whirl pooling technique). Here are three examples of potential customisable chilling profiles that could be available:
Immersion chilling - Personally, it takes me 5 min to chill my post boil wort from 100 degrees to 80 degrees. Assuming an exponential temperature drop, applying the correct utilisation factor would give you an approximation as to how many additional IBUs you would expect from these 5 minutes. The profile would let you choose how long it takes you to drop a given quantity of liquid, from 100*C to 80*C. The utilisation would be calculated from these two points.
- Counter flow chilling - as you are effectively only chilling the wort as it passes through the chiller, the wort remaining in the kettle during the transfer is still over the isomerisation temperature - increasing your bitterness. I'm not too sure how the mathematical mechanics would work behind this calculation however. I guess it would be based on time to empty kettle, and also method of extraction, either by pump (constant flow rate) or gravity (decreased flow rate as head pressure in kettle drops).
- Nochilling/Icebath chilling - This would pretty much be calculated just like immersion chilling, as the whole of the liquid is being cooled, as opposed to a small portion at a time (like counter flow chilling). From Relaxedbrewer's article, it was noted that it took 2 hours and 15 min to drop 27L of water from 100*C to 80*C in a brew kettle with the lid on (assume this would be similar for nochill cubes).
I understand that brewing isn't about science and mathematics, its more crafting something and letting your physical senses tell you how bitter something is or should be. This can be learnt through practice and replication on your own brewing setup.
I feel like these two options would help make recipes more transferable between systems and help brewers scale up or down recipes as well as helping brewers make the same beer on two different systems.
Obviously it won't be perfect, but it should make it easier.