I’ve posted previously about what the consensus is on full rolling vigorous boil vs. simply a boil that disturbs the top of the liquid.
I have to tell you that listening to Dr. Bamforth today on the BeerSmith podcast…he makes some pretty good darn arguments about the need for a long vigorous boil. Worth a listen at the very least, I think I learned more about the boil today than in my entire 3-4 years of brewing!
I listened as well. Hasn’t Brulosophy done an experiment on DMS levels in a 60 vs 90 min boil and found no evidence of DMS either way? Not sure if vigor of boil was stated in that experiment (if remembering correctly).
It wasn’t just DMS that was the issue (also he mentioned that many commercial breweries today have high levels of DMS, perhaps just not perceivable by the consumer), it was also an issue of hop isomerization that I thought sounded important.
The advantage of a rolling boil is that it agitates the liquid and so speeds up chemical reactions in the same way that stirring does. If the surface of the wort is turning over, it means hot liquid is convecting from the bottom and the whole volume is circulating. That should be sufficient to keep the wort continuously agitated. There’s no need for a more violent boil.
I’ve noticed an impact on boil-off rate (vigorous evaporates water faster). For this reason alone, I like the vigorous to help shorten the brew day.
Low isomerization can be countered by using more hops. I recently tried a beer with only a 20 min, boil. It was not lacking in hop flavor, bitterness, or clarity.
I’ll report back when it’s done but my Dubbel that is cold conditioning right now used a very vigorous 30 minute boil. Like Denny said, I just adjusted hop amounts up to compensate.
Maybe my palate isn’t very keen but I can only recall two beers ever poured for me at microbrew/brew-pubs in the past 15 years where I could distinctly taste DMS when it would be considered a flaw for the style. I appreciated the podcast but feel that vigor of boil connection to DMS is a bit overblown, especially at the homebrew level. Denny’s comments about recently enjoying the heck out of a 20 min boil beer (granted, a highly hopped IPA could easily mask this flaw) and Dave typically operating at 40 min boils supports this.
I mash for 40, not boil, at least not usually. But I’m heading there.
Personally I’m of the opinion that boil vigor is way more important than boil time. You need that wort to be practically jumping out of the kettle to get the best clarity and hop utilization, oh and I’m sure it doesn’t hurt either getting the DMS precursor out of there. If you only simmer the kettle or do a weak rolling boil, it’s not going to be as effective as the leaping geyser type effects. I learned this from the guy I know who makes the best homebrews of most my other buddies – he says don’t dick around with adjusting heat, just friggin crank 'er up, as long as your kettle is big enough to hold it anyway. Make sure your kettle and your heat source are big enough for jumping and bouncing and leaping of vigorously boiling wort. If you can do that, then I see no reason why 20-30 minute boils shouldn’t work. I’m heading in that direction, already tried 45 minutes on a few batches and it didn’t hurt anything. And yes I boil very vigorously, have for years.
I agree
I can definitely get that jumping boil effect with my heat source. I may try the 45 min hard boil on my next batch.
My last batch was boiling very, very hard. I don’t plan on exceeding 30 minutes anymore.
1.2 gallons is my sweet spot and at that volume, I generally use less than 1 Oz. hops total for the types of beers I brew.
If you boil hard & short, then it really just becomes a balancing act between time vs. hop bitterness. I might go so far as to round all my hop additions to the nearest half-ounce or whatever, then calculate how many minutes I need to boil to get the IBUs that I want. So, if I want 30 IBUs and I need to boil for exactly 38 minutes with a half-ounce of hops to get that many IBUs, then by golly I might just do it that way. As a small-batch brewer, this will make storage of leftover hops easier for me. But for you big batch guys, round to whole ounces and do the same thing if you want.
I like it Dave. I think this is how in operating from now on.
I boil so hard last Saturday that I need to change my gal/hr loss as a result.
This was my first batch with the 12 qt. pot so I let it rip.
I never would’ve thought to approach it that way. I might try this on my next hoppy beer.
The one downside I can see to a shorter boil is that my efficiency will go down since I will collect less wort. A shorter boil won’t give me time to boiloff a larger volume.
Couldn’t you just adjust the grain bill accordingly?
What about color and melanoidin development?
thinks to self - ‘and he thinks that’s a bad thing?’
I’d thought of that as well. But do I need to get back into my higher efficiency = lesser malt flavor theory again? 
Granted, yes, folks will lose a couple points of efficiency from boiling less. Keep it in mind. Probably not huge, but slightly.
yeah, but it will take a few brews to know how much