I was reviewing the Deschutes Black Butte Porter clone recipe, an excellent brew IMO, and noticed it called for 0.5 oz of Galena 13% aa hops at 90 minutes boil.
How much more bittering can you achieve at 90 minutes versus 60 minutes?
Thanks in advance for your comments,
very little. Here’s a graph
eta: posted just after denny’s reply. I’ll leave my reply here.
How much more bittering can you achieve at 90 minutes versus 60 minutes?
Probably not much. There is some data in this
Basic Brewing Radio: November 1, 2018 - IBUs vs Wort Gravity and Hop Stand Temps
“Dr. Chris Hamilton of Hillsdale College in Michigan shares results of his experiments testing the effects of increased wort gravity and different hop stand temperatures on IBU measurements. […]” (also eta: the data in the 0 to 20 min range is different between the two.)
that seems to match the data in the classic Tinsenth IBU lookup table in the 30 to 60 min range. (eta: or see the chart that denny mentioned.
90 minutes
Is the additional 30 minutes of boil also for creating flavors from the malts? (eta: FWIW, I tend to mash/boil longer as the beer gets darker. My best barley wine was a 2 hour boil.)
Some research has shown it peaks @ 60 minutes and actually goes down if boiled longer. I’m not sure where I heard it, but it’s out there somewhere.
Bottom line is that once you hit one hour, the bitterness remains largely unchanged after that. I never worry about boiling a hop longer than an hour and every time I did, the bitterness was fine.
In light of everyone’s replies, I wonder why Deschutes is doing that; maybe they want a longer boil time to boost ABV.
A long boil is an expensive way to get a higher OG. Simply starting with less water makes more sense financially. There must be a flavor-related reason.
I wouldn’t assume a clone recipe is a good reflection of their commercial process or a reflection of their modern process.
The quantitative answer is: about 7% more IBUs at 90 minutes vs. 60 minutes. Or conversely, a 60-minute boil will give you about 93% as much IBUs as a 90-minute boil.
Source: Hop utilization table from How To Brew by Palmer, shown in the green & white table here:
Assumption: OG 1.060 (pretty close, right?)
Simply divide the utilization factor of 0.226 @90 minutes by the factor of 0.211 @60 minutes to understand the effect.
If I use an IBU formula at each timing for the Galena hops you specified, 0.5 oz 13% aa, with an assumption of a 5-gallon batch, I get 25.7 IBUs at 90 minutes and 23.6 IBUs at 60 minutes. Then 23.6/25.7 = 92%. Or the inverse would be an extra 9% IBUs at 90 minutes vs. 60 minutes. Oh look, my numbers work out pretty close.
But of course, people will say “this is only calculated, you would have to measure in a lab to know for sure” or “you probably can’t taste the difference anyway”. But in my experience… I would say, this is a pretty damn close estimate of reality.
And bottom line: Yeah, while you might get a couple more IBUs, you probably can’t taste the difference.
Also, Deschutes might not boil 90 minutes. That is indeed expensive. A clone recipe might choose to do so, because it wasn’t written by Deschutes but a homebrewer probably, doesn’t cost a homebrewer much to boil a little longer if they want an extra couple IBUs just to lean on the safe side or for whatever other reasons (e.g., DMS concerns which are largely baloney).
To rephrase and reemphasize the bottom line: Feel free to boil for 60 minutes instead of 90. It’s not gonna matter.
Seems more likely it’s to develop maillard reactions for flavor. Or maybe that’s just how their equipment works.
Deschutes provides homebrew recipes of many of their beers. Seems likely the recipe came from them. The other thing to consider is liquor requirements. Maybe the recipe is written to use more water to boost efficiency which would require a longer boil.
Another point to consider- you can have a 90 minute boil and starting hopping at 60 min.
Regarding Denny’s post that was the 9th reply on this topic, adding water to boost efficiency would be expensive based on 30 minutes additional boiling time.
A lot of BTUs for a tidbit of efficiency seems like.
Thanks to all that have replied to date.
For a brewery, yes. For a homebrewer, not so much. Do we know that Deschutes actually dies a 90 min boil? And my experience, again on the homebrew level, is that it provides what I consider to be a pretty fair boost.
Agreed! That’s the great joy of being a homebrewer. We never have “bean counters” telling us we can’t spend two more bucks for a 5-gallon batch or the marketing folks telling us not enough patrons would consume what we wanted to brew.
commercial boil off rates are substantially lower than homebrewers. it might be a matter of necessity to accomplish what homebrewers can do with a 30 or 60 minutes boil.
Why even assume they do a 90 minute boil? It’s a homebrew recipe.