Hi
Can anyone explain the high IBU’s that are calculated for this recipe? I have put the numbers into Brewer’s Friend and am not getting anywhere close to the 120 IBU’s that are stated for this recipe. And that’s with Tinseth and Rager. Is there a 3rd IBU calculator that I am unaware of?
Thanks in advance
Phil
We need more information. What is the recipe?
120 IBU is physically impossible anyway. Around 100 mg/L is the theoretical saturation limit for iso-alpha acids in a low gravity wort, and that is greatly reduced by both increasing gravity, and, counterintuitively, increasing hop rates. The most that will probably ever occur in finished beer is still shy of 80 IBU. High advertised IBUs are just machismo on the part of brewers. Ignore the numbers, brew the recipe, and see how you like it.
(Also note that the Tinseth and Rager calculators are capable of generating such an impossible number. But remember that these tables are really just their individual SWAGs at what they were getting on their own systems back in the day, extrapolated out to increasingly imaginary ranges. The fact that these tables have been canonized and enshrined in every book and software program published for a couple of decades tells us a lot about homebrewers’ obsession with numbers, but very little about what’s in our beer.)
Yeah mate, I know they’re a minefield and that some breweries rip the arse out of their calculations. But these numbers seem way OTT. I really would like to make this brew as good as I possibly can because the original is an epic beer. And the thought of having a keg full of the stuff has me salivating.
Ah, that explains it. Historical British beers are very often hopped at an extremely high rate. That’s just the way it was back then. If you look at the Durden Park Circle recipes, some of them have unbelievable IBU levels…but that’s what they did.
ETA: I took the 1856 to be the year it’s from. Probably totally off the mark on that.
Remember that these historical beers had enormous hop charges, but we don’t really know the IBUs. Nor did they. They were brewed according to custom, and empirically developed recipes, but the science was still nascent. Moreover, looking at old recipes in, e.g. Ron Pattinson’s work, you’ll see that the hops were regularly several years old and were not stored in what we would regard as the proper manner. Reproduction of historical beers really is more of an interpretive art than anything else. But great fun.
Den
I think you are correct in that the original year of the recipe is 1856. That is pretty much what The Kernel do. They have loads of historical recipe beers. My query is how, with that amount of hops in the recipe, did the calculator churn out a number of 120.1 IBU’s? It doesn’t seem possible. I have reached that number using Brewer’s Friend but I had to use a lot more hops and use Rager as the calculating tool.
Sure, it’s entirely possible to ha e numbers calculate that high. I once made an American variations that called to 135 IBU. Obviously, as pointed put in the Durden Park book, it’s impossible to know what the AA of the hops in the original recopes is, and they certainly didn’t know either. Just the amount.
And a side note on calculations…when we interviews Glenn Tinseth for Experimental Brewing, he made it clear that unless you used whole hops, had a brewing setup exactly like his and chilled for the same length of time he did, there was no reason to expect you’d get the same results he did. The takeaway is that IBU calcs are highly variable and not necessarily reliable. When we did an experiment to test that, we found results as much as +/- 50% from the calculated value.
Kernel Brewing in London re-created this beer from an 1856 Barclay Perkins recipe. Everything in the recipe submitted to Zymurgy matches up with Barclay Perkins IBS ex recipes from the mid 1850’s all the way to the 1950’s except these IBU numbers. The OG, the ABV and SRM all line up with the original but the IBU’s of Barclay Perkins Stouts are generally in the low to upper 50’s. The sites that rate commercial beers do not give an IBU for the Kernel commercial beer so it would seem the contributor of that recipe took a WAG.
I’m curious. If I get the time I’m going to see if I can find anything in Ron’s work giving original hop rates for these IBS ex’s of the period. It would have been scheduled in pounds of hops per quarter of malt. From this we might take our own WAG at the alpha content of the hops and guesstimate a bitterness number. Then taking into account the fact that vatting would have further reduced bitterness, which a modern brewer will not match, we could come up with our own adjusted guideline for historical reproductions also based on quantity of hops rather than IBU calculations. Going out on a limb, I’d bet we’d want to use no more than half the weight of hops, scaled down, that the original brewers used.
I have emailed The Kernel, asking them for their estimated IBU’s for this beer. They were very helpful when I asked them about the recipe on this website so I am hopeful they will come back to me with something.
I think the IBUs in a professional system can be higher than in a homebrew setting because the boil temperature is higher in a tall tank due to water pressure. Perhaps I’m imagining this.
Anyway, the purpose of IBUs in a beer that should be aged is so that there is a reasonable amount of bitterness around when you want to consume it, maybe 6-18 months after brewing. For this purpose, a calculation of 70 IBUs or 110 IBUs is pretty much the same thing.
Yeah, temp has nothing to do with once you reach isomerization temp.
Kettle geometry and circulation can affect utilization rates, as well as the amount of oils retained in wort. The bigger the batch the more you get from the hops, it seems. Some things just don’t scale precisely from commercial to homebrew batch size.
I haven’t looked at any of Ron’s stuff. But looking for something else in the Wahl-Henius Handybook (1901,) I happened to glance at a table in the section on brewing in England showing hopping rates for various beers. It gives Imperial stout at 14-15 lbs per qtr of malt, translated to 2.5-3 lbs per American barrel (31.5 US gal) and a wort density of 20-25% Ballling (=°P.) For Russian export, 16 lbs per qtr, 3.25 lbs per US bbl, and above 25% B. This puts us in the range of 1.5 oz/gallon on the homebrew scale. Generously allowing 4% alpha acids in the hops (I think that is quite generous for hops up to a couple of years old stored at cellar temperature, as the best hops were reserved for pale ales) this will indeed, back of the envelope style, give a calculated (Tinseth or Rager) IBU value of easily 120, assuming all the hops boiled at least 60-90 minutes. Which is bull, but – it jibes nicely with the value given in the OP’s recipe.
EDIT – CORRECTION – My apologies. Forgoing the back of the envelope and actually doing the calculations properly, I get high 80s Tinseth. Anyway, we know they used a $#!? ton of hops. Which we already knew.
FURTHER EDIT and note to OP: I still can’t get anything close to 120 out of the recipe as given, using the standard tables. 60s at best. Is it possible a hop was omitted from the recipe as published? I look forward to hearing whatever response you get from The Kernel.
I notice another curious thing about this recipe. It’s meant to be an 1856 recipe. It contains anachronistic malts, Munich and crystal, which might be chalked up to the brewers’ artistic license. But coming from that slice of history tucked between the Corn Laws and the Free Mash Tun Act, that sugar absolutely does not belong there! Though perhaps it helps to dry it out and sharpen it up in the absence of vatting?
Got a reply from the Brewery, guys.
Hi Phil,
We calculate about 100IBU for that beer. But above 80 IBU you can’t
really judge IBUs much at all, and in such a big beer with a high
finishing gravity it actually does not even taste that bitter (to my
mind, at least). Though you do have a roasted malt bitterness
accompanying that from the hops. We just packed the latest batch
yesterday - it makes the brewery smell amazing.
All the best,
Evin
And this was the original response when I enquired about the clone recipe.
Hi,
It is sort of right.
We use:
Pale Marris 78%
Brown 10%
Black 8%
Amber 4%
We then use sugar, at 8% the total weight of grain, if that makes sense. A blend of white, light brown and dark brown.
We use no crystal malts. No cara, or carafa. It is a bitter, ‘dry’ beer.
We add most of the hops at the beginning of the boil, and sometimes some more at 30 mins, but nothing after that. We also only boil for 60mins now. We bitter to a theoretical 90.
We mash very low (for us) at 65C, which is 3.5C lower than our pale ale mash temp. We aim for a finishing gravity of 1.022-1.025, with a start as close to 1.096 as possible. We have to run off less than normal. We stop the run off at around 13P, so there is plenty left in the mash, but any more ‘low’ gravity runnings will lower the finally gravity of the finished wort.
We add the sugar to the boil, when you add protofloc. We use finings on all the beers as the protein can inhibit the yeast. We use US05 (shock horror!) for our imperial stout as the pitch rate for the size batch we have is just too much yeast and we rarely have enough to crop to pitch more than 100L in one go.
That is a lot of ‘we this, we that’ but I hope it is helpful. If you have anymore questions, shoot them through. And if it all goes wrong, rdwhahb!
Cheers,
Ben
Definitely brewers artistic license.
I did do some research on Ron’s site for Barclay Perkins Russian Imperial Stouts and the grist for the 1850’s was only Pale (63.5%), Brown (22.56%), Amber (11.19%), and Chocolate (2.75%) malt.
The hopping rates were 15.19 pounds per quarter | 9.6 pounds per brl.