tom_hampton said:
I can't speak for anyone else here, but I'm under no delusions of the unlimited upward accumulation of bitterness.
Hi Tom! And welcome back!
I knew I took a chance in drawing you out with that post. I agree, you're not one to whom I was speaking. Neither was Brad, nor the idea of calculating whirlpool bitterness. I have no doubts about your abilities. You're one of the most advanced brewers I've come across in forums without actually meeting in person. Plus, you race cars and I'm a NASCAR fan.
tom_hampton said:
That's not the point, though. To take your position to the extreme, there is no point in calculating it at all, because so many factors can affect the final result. The point is that you control those parts of the process that remove IBU and hop flavors from the wort/beer so that they are approximately constant.
Indeed, taken to the extreme, that could be one of my points. My actual point was NOT to take it to an extreme in either direction because of the variations between setups. My point is that IBU calculations are useful as a relative metric.
In other words, once the beer is brewed and tasted the brewer can review the recipe and say "oh, that's what XX IBU tastes like." and with time, modify that perception to include various hop types, cohumulone levels and all the rest of the variables. Thus, as process and equipment improves, so will hop utilization and the brewer can calculate the adjustment.
Take that further, a brewer can read someone else's recipe and come up with something very similar, through a combination the recipe specs and understanding their setup.
These are the things that make a formula and recipe software valuable. Which is exactly the point I think you're making. Correct?
I work as a pro brewer. I brew in a pub and consult for startups. Before I posted, I did a reality check of both literature available to me and polled a few other brewers, ranging from 5000 to 140,000 bbl in size.
Whirlpool hop accuracy has only become a concern because it's now fashionable to add hops there. Plus the burst hop method to enhance aroma from a hop charge. None of this really existed as a concern or technique before the hop shortages began. When PtE was developed, there were no hops that cost more than $5/lb. Now, it's closer to $15 on the wholesale end. So, there is much more concern about maximizing return from a much more expensive ingredient.
My other point is that since this technique and its results are relatively new, there's scant data out there to show correlation between techniques and results.
tom_hampton said:
The calculation still has value.
100% Agreed! The current calculation that Brad is using has allowed me to dial my hop utilization back from 120% to 100% based on my most bitter beers.
tom_hampton said:
There are beers below 65 IBU. Some people even brew beers with less than 30 IBU, GASP!
Indeed! And these were the norm long before the burst/whirlpool hopped palate busters of today. The previous IBU calculation model served those beers very well. Hence, why I'm pointing out that once saturated, the IBU number isn't all that important.
I have core products that range from 14 to 88 lab measured IBUs. My top seller is a 26 IBU Export Pilsner and my third is a 34 IBU Red Ale. Second place is, of course, IPA at about 70 IBU.
My process is:
75 minutes kettle fill
15 minute rise to boil/hot break
90 minute full boil
20 to 45 minute whirlpool
(longer WP times for IPA/DIPA because it enhances hop flavor)
30 minute stand/settle (gravity, it only works so fast)
40 minute chill (valves wide open, this is the flow rate of the Hx)
A FWH then is in there for up to 5 hrs. Yet, what I get is flavor, not increased bitterness.
The Pilsner has an aroma charge at flameout which, according to the OP, should contribute more than 20 IBUs to the beer. It doesn't. It contributes the expected 2 IBUs even though it had 90 minutes of contact time at or above 195F.
The red follows a classic, all kettle addition hop schedule of an American Pale Ale. Even with the extended time post boil, it nails 34 to 35 IBU.
I was taught that only fully isomerized alpha acids persist in a beer. I was taught that it takes at least 45 minutes of boil to get strong persistence and that it is the boil agitation that does the trick, along with heat. Given that sweet wort is often surprisingly bitter but the bitterness fades with fermentation, that lesson has served me well.
My American Wheat's bitterness comes from a burst hop addition at 10 minutes of 14% aa Sorachi Ace. Twelve days into fermentation and it's pretty bitter at 20 IBUs. But, by packaging it mellows to 14, which correlates to the expected isomerization. In return, I get a pleasant light lemon aroma and a beer that tastes like a Japanese lager, rather than a flabby American wheat.
tom_hampton said:
So, I try that...and again make an adjustment based on my perception of the result and the math. Maybe now, I think that its not quite bitter enough. So, I adjust the steeping time up to give me 5 more IBUs (calculated).
Exactly! If you think it needs a change, you do it. That's what being a brewer is all about! Quantifying it with a formula is a relative metric, not an absolute.
I'm certain that if you had the added data of ACTUAL IBUs, you'd hone that even more. Ironically, you could likely find that the IBU number doesn't change much, but the perception of aroma and flavor does. There's taste panel data from breweries that show bitterness perception is lower when hop flavor/aroma is lower. I think this taste panel data has shown up in AHA conference presentations.