How long do YOU boil ?

[RPh_Guy]

FYI Brewhouse efficiency is about how much of the sugar from the grain makes it into the fermenter. Boil length doesn't alter that.

Couple other processes not mentioned:
Mineral precipitation (and resulting pH drop)
Degradation of mycotoxins

 

[couchsending]

On the other hand, precursors to DMS and diacytl may actually increase during an extended vigorous boil. Combined, these observations suggest that a 30 minute boil might be much better than 60-90 minute boils.

Where did you read this?

The exact opposite of everything I’ve ever read in regards to DMS and I’ve never heard of a diacetyl precursor being formed in the kettle.

The main precursor for DMS is SMM correct. I believe it’s half life is 35 minutes at 212 and 5.4 pH. That number drastically changes as elevation increases and also changes with pH.

Leaving wort above 85c for an extended period of time without boiling or movement can increase the presence of DMS in the final beer.

I boil at 201. Everything gets 90 minutes minimum. Sometimes big beers get 3-5 hours.

Never too rigorous of a boil however.

Many more reasons to boil longer as well.

 

[day_trippr]

I went back through my brewing notes.[...]

It comes down to how "fuzzy" one allows the numbers to be for the end result to be "within expectation".

If one allows an extra quart of preboil, and a quart short post-boil, and a few OG gravity points low, the result will no doubt be near 'nuff to be "the same".

But, obviously, it cannot be...

Cheers!

 

[iancl]

A more interesting question would be:

What happens during the boil and how long do each of those processes take?

RPh, I would be interested in your take on the science of the boil. Please.

 

[balrog]

I thought it was proven long ago that the mycotoxins were easily dissipated by proper passivation techniques? Just kidding. Never heard of mycotoxins. More to read.

I will seriously say however, that 30m mashes did *NOT* work for my amber and altbier recipes, as the shorter than 60m mashes were noticeably less flavorful. To @day_trippr 's point, the lighter recipes work well 'nuff with 30m mash, but I am *SURE* that the same flavor extraction reduction happens, but is mitigated by the hop flavor I use in those lighter-but-mashed-shorter recipes. As to the boil, I am still re-re-thinking it.

 

[BrewnWKopperKat]

I am still re-re-thinking it

Back in early 2018, with my darker BIAB recipes, I experimented with shorter mashes and boils. Didn't like the initial results but sometimes it takes time to "dial it in".

Along comes a HomeBrew Con 2018 presentation on boiling (and a followup article in Zymurgy). I set the short mash/boil experiments aside (didn't dive deeply into the article at the time) - and went back to a more traditional 60 min mash / 60 min boil for ambers, browns, and porters.

This recipe [link] could be interesting for a personal exBEERiment: challenge the claims made in the recipe by brewing it "as is" and brewing it as a 20 min mash / boil.

 

[Brooothru]

FYI Brewhouse efficiency is about how much of the sugar from the grain makes it into the fermenter. Boil length doesn't alter that.

Couple other processes not mentioned:
Mineral precipitation (and resulting pH drop)
Degradation of mycotoxins

Good points to consider. Are those factors degraded or adversely impacted by reducing boil time to :30 minutes? Just trying to find a balance pro/con, focusing on negative factors, as to whether testing shorter boils is worth my time. As it is, my brew days keep getting longer and longer. The good news is I believe my beers keep getting better, an opinion reinforced by higher scores in competitions.

What has really extended my brew days however is the mash. For the last 5 or six years I've been doing step mashes, attempting to establish 'rests' at specific temperatures to capture the most active set points and durations for the various enzymes to work at their highest efficiencies. It has paid off by upping my mash efficiencies, now consistently in the low to mid-80s. There's also been a slight uptick in overall brewhouse efficiencies as well. Of course, there is no free lunch. My mash time has gone from :45 minutes to an hour "till the iodine turns blue" to currently more than two hours. I haven't done an iodine test in years because I'm not concerned with 'conversion' per se, but rather what is being produced during the conversion. I know that after two hours in the temperature range between dough-in and mash out, conversion will occur.

By resting at different temperature and time set points I can shape the wort to the beer style I'm trying to achieve, not unlike what we do with brewing salts to shape the strike water to match the beer style. Right now I alternate between 3 Hoch-Kurz mash profiles (malty/sweet, dry/light, and 'in-between'), based on the work done by Brauwelt and the compilation of other peoples' work by John Palmer. I'm very pleased with the results, but at the cost of a lengthened brew day.

Ergo, the desire to see if cutting 40-60 minutes out of the boil time can help trim my time investment back to a reasonable duration. Advice and suggestions are encouraged.

Brooo Brother

 

[Spartan1979]

It may be that 60-90 minutes mash and boil times could go the way of secondary fermentations. People tend to follow long accepted dogma right up until someone points out that that particular emperor isn’t very well dressed.

That may be true. After reading several Brulosophy experiments I have to wonder if anything makes a difference! But I know my methods produce good beer so I'll probably stick to most of them.

 

[Brooothru]

Where did you read this?


Leaving wort above 85c for an extended period of time without boiling or movement can increase the presence of DMS in the final beer.

I boil at 201. Everything gets 90 minutes minimum. Sometimes big beers get 3-5 hours.

Never too rigorous of a boil however.

Many more reasons to boil longer as well.

I can't quote the exact source. I believe my 'opinion' (suggesting that extended boil time may increase DMS) probably came from the LoDO brewing website or forum posts. It must be true if I read it on the internet .

And yes, SMM is the precursor to DMS, which is increased by the presence of dissolved oxygen. Boiling and movement within the wort cause oxygen in the air to increase the levels of dissolved oxygen in the wort, so presumedly a more vigorous boil would result in more DO in the wort. So would additional time at a vigorous boil. It could be argued that a 'simmering' boil is similar in degree to a "time without boiling or movement". If that premise is accurate then "(L)leaving wort above 85c for an extended period of time..()..can increase the presence of DMS in the final beer." That's all I've got to support my opinion.

Like you I use a lower boil temperature (98-99C) and have been using 75 minutes for everything. That said, I really can't see any advantage to boiling 3-5 hours. I'm not a chemist or microbiologist, just a retired airplane driver trying to make better beer. I hope my posts don't come across as a know-it-all or some kind of authority on the topic at hand. Quite the contrary, I spend time here to learn from those people who are scientists or have skills and experience with the topic at hand, and to ask questions as well as share my experiences and random opinions. But I'm not afraid to challenge conventional thinking (whether my own or someone else's) and gladly accept being corrected in any wrongful theories or cock-a-mammy ideas. That's how we learn and advance.

Cheers!

Brooo Brother

 

[couchsending]

I can't quote the exact source. I believe my 'opinion' (suggesting that extended boil time may increase DMS) probably came from the LoDO brewing website or forum posts. It must be true if I read it on the internet .

And yes, SMM is the precursor to DMS, which is increased by the presence of dissolved oxygen. Boiling and movement within the wort cause oxygen in the air to increase the levels of dissolved oxygen in the wort, so presumedly a more vigorous boil would result in more DO in the wort. So would additional time at a vigorous boil. It could be argued that a 'simmering' boil is similar in degree to a "time without boiling or movement". If that premise is accurate then "(L)leaving wort above 85c for an extended period of time..()..can increase the presence of DMS in the final beer." That's all I've got to support my opinion.

Like you I use a lower boil temperature (98-99C) and have been using 75 minutes for everything. That said, I really can't see any advantage to boiling 3-5 hours. I'm not a chemist or microbiologist, just a retired airplane driver trying to make better beer. I hope my posts don't come across as a know-it-all or some kind of authority on the topic at hand. Quite the contrary, I spend time here to learn from those people who are scientists or have skills and experience with the topic at hand, and to ask questions as well as share my experiences and random opinions. But I'm not afraid to challenge conventional thinking (whether my own or someone else's) and gladly accept being corrected in any wrongful theories or cock-a-mammy ideas. That's how we learn and advance.

Cheers!

Brooo Brother

Yeah I think you might have a few signals crossed

The lowdo guys definitely advise boiling for long enough to eliminate DMS which in most cases is 70 minutes. However they also recommend trying to minimize boil off to a certain percentage and keeping the boil to somewhat of a minimum. This is more about thermal stress on the wort than anything else. An attempt to preserve malt flavor and aromatics in delicate beers.

The whole idea of needing a very rigorous boil is a bit of a myth that’s been debunked for a while. Depending on the style and what you’re trying to achieve You can do more damage to the wort by boiling too intensely for too long a period of time but it doesn’t have anything to do with diacetyl or DMS.

There are quite a few instances however where you might want to boil for extended periods of time. Many lambic brewers boil for 4 hours +. I believe Weldworks boils their imperial stouts for up to 36 hours. This is SOP for many of the breweries brewing those THICC high ABV pastry stouts everyone froths over. Their evaporations rate is closer to 3.5% however so on the Homebrew scale you could probably accomplish the same thing in much less time.

 

[bracconiere]

it takes me 3+ hours to boil off 3.5-4 gallons to get 10....so i'd say somewhere around 200 minutes...(i got all you beat )

 

[Brooothru]

Back in early 2018, with my darker BIAB recipes, I experimented with shorter mashes and boils. Didn't like the initial results but sometimes it takes time to "dial it in".

Along comes a HomeBrew Con 2018 presentation on boiling (and a followup article in Zymurgy). I set the short mash/boil experiments aside (didn't dive deeply into the article at the time) - and went back to a more traditional 60 min mash / 60 min boil for ambers, browns, and porters.

This recipe [link] could be interesting for a personal exBEERiment: challenge the claims made in the recipe by brewing it "as is" and brewing it as a 20 min mash / boil.

I'm not a fan of short mashes. In many ways I think the mash is much more important than the boil which I view as mainly the mechanism to isomerize hop oils. I've brewed Evil Twin several times and think it's a very solid recipe. The directions make an interesting point with regards to 90 minute boil verses anything shorter:

DIRECTIONS
Single infusion mash at 154° F (68° C) using a ratio of 1.3 quarts water per pound of grain. While you could go with a shorter boil, the 90 minute boil enhances the blood-red color. Cool the wort quickly after the last hop addition to retain as much hop aroma as possible. Optionally, dry hop with more Centennial or Amarillo if you’re a real hop monster. Carbonate to no more than 2 volumes and serve at 45° to 55° F (7.2° to 12.8° C).

The highlighted portion points out that the extended boil is necessary to achieve the distinctive color, in this case an SRM of 17. This is the Maillard effect, same as when you grill a steak. Looking back at my brew notes I see that my past "Twins", boiled at 60-75 minutes, had an SRM of 12-13. That's one of the few areas I can find that show conclusively that extended boils result in discernible differences over a :30 minute boil. OTOH there's ample science easily found in the literature to support complex, lengthy step mashes. While I'm interested in finding ways to shorten my brew day, I've only found reasons for extending my time in the mash. I'm still hoping to find real science, not opinion or inertia, that can convince me that I'm not compromising quality by shortening boil time.

Brooo Brother

 

[Brooothru]

Yeah I think you might have a few signals crossed

The lowdo guys definitely advise boiling for long enough to eliminate DMS which in most cases is 70 minutes. However they also recommend trying to minimize boil off to a certain percentage and keeping the boil to somewhat of a minimum. This is more about thermal stress on the wort than anything else. An attempt to preserve malt flavor and aromatics in delicate beers.

The whole idea of needing a very rigorous boil is a bit of a myth that’s been debunked for a while. Depending on the style and what you’re trying to achieve You can do more damage to the wort by boiling too intensely for too long a period of time but it doesn’t have anything to do with diacetyl or DMS.

There are quite a few instances however where you might want to boil for extended periods of time. Many lambic brewers boil for 4 hours +. I believe Weldworks boils their imperial stouts for up to 36 hours. This is SOP for many of the breweries brewing those THICC high ABV pastry stouts everyone froths over. Their evaporations rate is closer to 3.5% however so on the Homebrew scale you could probably accomplish the same thing in much less time.

I see what you're saying and concur I might have formed some misconceptions. I'll have to revisit the literature to set my thinking straight. I'd forgotten about the thermal stress factor in vigorous boil, and focused more on the aspects of the wort absorbing more oxygen through the motion of boiling. Two very good reasons for abandoning rapid boils.

The hyper-extended boils for Lambics and Trappists (as well as the shiny new object, pastry stouts) is interesting. I spent quite a bit of time in Belgium during the 90s and beyond, but never developed a taste for them. Consequently I never researched the styles or the brewing processes associated with them. Sure am glad I don't have to pay Weldworks' energy bill, though.

Brooo Brother

 

[RPh_Guy]

RPh, I would be interested in your take on the science of the boil. Please.

I really can't give all the processes and figures off the top of my head and don't really have time to put everything together right at the moment. Sorry.
For most homebrewers, shortening or lengthening the boil likely won't cause any significant problems (that aren't already present).

However, for best results you'll want to minimize boil-off rate to no more than 6-10%/hr and boil for no more than 60-70 minutes. You'll also want to achieve a starting kettle pH of around 5.4 or higher (measured at 68F), and then add acid toward the end of the boil to target pH 5.0-5.2 (at 68F)
http://www.********************/uncategorized/low-oxygen-boiling/

 

[Brooothru]

I really can't give all the processes and figures off the top of my head and don't really have time to put everything together right at the moment. Sorry.
For most homebrewers, shortening or lengthening the boil likely won't cause any significant problems (that aren't already present).

However, for best results you'll want to minimize boil-off rate to no more than 6-10%/hr and boil for no more than 60-70 minutes. You'll also want to achieve a starting kettle pH of around 5.4 or higher (measured at 68F), and then add acid toward the end of the boil to target pH 5.0-5.2 (at 68F)
http://www.********************/uncategorized/low-oxygen-boiling/

I read the cut and paste you linked, especially the highlighted portions. Kunze was repeatedly quoted stressing "reduced" boil times as well as a less vigorous boil. "(L)less vigorous" I get but still can't find a definition of "reduced" boil times. From you post I get 'no less than 60' and 'no more than 70' as being general guidelines. Is this essentially correct?

Also good info on pH. By using the Water Calculator and adding judicious amounts of acidulated malt in the grist I can get my initial mash pH (measured ~5 minutes after mash-in at 'room' temperature) to be spot on. After re-reading Palmer's section on "Understanding Mash pH" I get the impression that any corrections should be delayed until after reaching saccharin rest temperature. Now you're telling me that I should also measure and correct both pre-boil and post-boil pH? I have mostly used lactic acid to correct for mash pH. Would this also be appropriate for adjusting high boil pH, and what about raising the pre- and post-boil pH of a wort that is too acidic?

If I'd only been this interested in chemistry as an undergrad....

Brooo Brother

 

[CharlieW]

Usually 60 min, but have extended it on occasion another 15mins or so to hit my volume.

 

[BrewnWKopperKat]

the boil which I view as mainly the mechanism to isomerize hop oils

It seems plausible that for hop forward styles and hazy styles, not much else would matter. For malt forward styles it seems plausible that other things could matter.

OTOH there's ample science easily found in the literature to support complex, lengthy step mashes.

Are you willing to share some of your findings?

 

[RPh_Guy]

From you post I get 'no less than 60' and 'no more than 70' as being general guidelines. Is this essentially correct

I don't think reducing the boil time below 60 minutes is necessarily a problem, but depending on how much you use pilsner malt it may be difficult to maintain a low boil-off AND fully prevent DMS.

I believe Kunze doesn't provide specifics because the minimal boil time is largely system-dependent and malt-dependent. At our level, 60-70 minutes should be the absolute maximum if you're looking to prevent thermally damaging the wort (combined with reduced boil vigor / low boil off rate). It's entirely possible you can boil for shorter duration without negative effects.

Now you're telling me that I should also measure and correct both pre-boil and post-boil pH? I have mostly used lactic acid to correct for mash pH. Would this also be appropriate for adjusting high boil pH, and what about raising the pre- and post-boil pH of a wort that is too acidic?

Let's say ideally you'll minimally need to use two separate pH corrections:
The first will be to attain "correct" pH in the mash. This will need to occur before the starch gelatinization; using acidulated malt is perfectly fine. This should provide a reasonable pH going into the boil kettle.
The second should occur toward the end of the boil.

If you want more tight control (which probably isn't necessary but would probably help improve consistently batch to batch), then additional corrections can possibly be made along the way depending on your process.

This is a lengthy thread, but worth the read since it has a lot of good discussion on mash and boil pH:
https://www.homebrewtalk.com/forum/...-brewers-do-not-mash-at-5-2-to-5-6-ph.671764/

 

[stevehaun]

The first will be to attain "correct" pH in the mash. This will need to occur before the starch gelatinization; using acidulated malt is perfectly fine. This should provide a reasonable pH going into the boil kettle.
The second should occur toward the end of the boil.

Why before gelatinization?

 

[kevin58]

I've been listening to an awful lot of Brulosophy podcasts while in the gym lately and I finally broke down and attempted my version of their short and shoddy experiments. I haven't been able to bring myself to do a 20 minute mash and 20 minute boil but I have been doing a 30 minute mash and 30 minute boil lately with zero negative effects on the finished beer (IMO).

When the weather began getting colder and my garden hose started freezing up, I moved from my big brew system outside to small batch brewing inside. I haven't brewed on the stove top in my kitchen for over 20 years and never all grain. The first batch I made took just as long as a full size batch and I thought crap, this isn't what I had in mind. So combining small batches with short brew days just makes sense. I've been spending the winter experimenting with beers and styles I've never made before and picking the ones I like well enough to ramp up on the larger system out in the garage when the weather warms up.

 

[Tobor_8thMan]

See, this is the crux of it. I think (though I don't presume to talk for) RPh is answering the question with a Socratic response (another question). At least I infer from his post that he is implying that "it takes as long as it takes." Or at least it should. But we humans are creatures of habit and too often succumb to inertia at the expense of reason. I'm as guilty as the next brewer. Yep, when I first started out I obeyed the mantra, "60 minutes for ales, 90 minutes for lagers." Got to drive off that DMS, don't ya' know. Out of laziness or complacency I finally gravitated to 75 minutes for both, figuring my boil-off volumes would be the same while not altering my lagers and maybe improving my ales.

But increasingly after reading and studying different fact-based observations and conclusions (not Brulosophy 'exbeeraments') I'm gradually coming to the belief that boil time is only a factor in hop utilization, and a "vigorous boil" for whatever length of time is actually a very bad thing for the flavor and stability of beers. By increasing my bittering hops by about 20% I can shorten my boil time to about 30 minutes (from 75). At least that's a rough number I get when I plug those numbers into BeerSmith using some past recipes. If true in the 'real world' of brewing, it begs the question RPh asked:

"What happens during the boil and how long do each of those processes take?"

Once you answer that question you'll have answered your original question. Then add to that, "And not one minute more."

Brooo Brother

Thoughtful input and great explanation. However, I do know, in my own experience, once I began the 60/90 mantra, depending on the malt, my brews have significantly improved. I guess, to each his own...

 

[RPh_Guy]

Why before gelatinization?

Alpha and beta amylase activity is the real "meat and potatoes" of the mash. Their action is affected by pH and it only starts once gelatinization occurs.

 

[stevehaun]

Alpha and beta amylase activity is the real "meat and potatoes" of the mash. Their action is affected by pH and it only starts once gelatinization occurs.

I thought you were implying that pH should be corrected before gelatinization occurs. This would require doughing in under gelatinization temp then raising to main mash temp. Unless you have the ability to step mash, this approach is not possible. In single infusion mashing, one really needs to have mash pH dialed in based on your water, malt analysis, and acid additions because you are doughing in above gelatinization temp.

 

[RPh_Guy]

I thought you were implying that pH should be corrected before gelatinization occurs. This would require doughing in under gelatinization temp then raising to main mash temp. Unless you have the ability to step mash, this approach is not possible. In single infusion mashing, one really needs to have mash pH dialed in based on your water, malt analysis, and acid additions because you are doughing in above gelatinization temp.

If you dough in above gel temp, you need to include your pH adjustment in your water or grist.

If you dough in under gel temp, you may correct pH during the mash.

In other words either way the pH should be adjusted before gelatinization.

 

[Immocles]

I've been listening to an awful lot of Brulosophy podcasts while in the gym lately and I finally broke down and attempted my version of their short and shoddy experiments. I haven't been able to bring myself to do a 20 minute mash and 20 minute boil but I have been doing a 30 minute mash and 30 minute boil lately with zero negative effects on the finished beer (IMO).

I've been going back and listening to skipped episodes of various podcasts. For whatever reason, I skipped a lot of those short and shoddy ones. I've been tempted to give one a shot now though, and after reading as many folks having success with shorter times, I might start trying to shave 10-15mins off my times as well. I don't mind mashing for a full hour or more, but I hate boiling that long. Even getting that down to 45 mins for non-pilsner malts would brighten my day. I've got a blonde ale coming up eventually. Maybe that will be the time to try.

 

[waldoar15]

It depends. I adjust for boil off rate/volume/gravity.

 

[CascadesBrewer]

I boiled for 60 minutes for most of my brewing span...cuz that is what Dave Miller and Charlie Papazian told me to do.

Lately I have been playing around with some 10 or 0 minute boil extract batches. How about that...you can actually get a rather bitter beer with only 10 minutes of boil...and even some bitterness in a beer with only flameout and dry hops. I am not convinced there is much bitterness difference between a 30 min addition and a 60 min addition.

I have lately tried out 30 minute boils for my series of single grain pale ales. The first 3 seemed fine (though the head retention on the 2 bottled ones was non-existent...not sure if the reduced boil could play into that). I just bottled another batch made with Wyermann Floor Malted Bohemian Pils that has the same 30 min boil. I brewed a Dark Mild today with a 30 min boil.

One downside I see is that with a 30 min boil, I don't have that extra 30 minute window to sit around and goof off!

A upside is that the reduced boil off means I have a little more room in my kettle for full volume mashes.