Boil time reduction : the science please

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neilzzzz

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Anyone have links to scientific papers or pro brew books to show evidence that short boil times create beer stability similar to 60/90 boils??

Older Pro brewing book are full of the chemistry behind 90/60 boils for reducing wort to increase shelf life.

Background.. I'm still brewing clear beer. Lager and English bitter.

When did this change? (I'm showing my age for sure here!) 😉

Where is the evidence in a published peer reviewed form?
 

McMullan

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I still do 90-min boils. If I were to do a 30-min boil I'd need to add a lot more hops - more hop vegetation - and risk introducing unwanted flavours. Especially with my English ales. I don't think there is any sound scientific evidence to support short boil times without a safe pressure capable kettle. It seems to be another home-brew fad based on superstitions. And you're right to question it.
 

Alan Reginato

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No, and I'm feeling lazy today.

But Wort Boiling - Brew Your Own

60 min is the most effective time/cost process both for hops utilisation and evaporates extra sparge water, wich increases brewhouse efficiency, to a target OG

But hot break form at less than 20 min. So a short boil is ok.
 

Miraculix

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I still do 90-min boils. If I were to do a 30-min boil I'd need to add a lot more hops - more hop vegetation - and risk introducing unwanted flavours. Especially with my English ales. I don't think there is any sound scientific evidence to support short boil times without a safe pressure capable kettle. It seems to be another home-brew fad based on superstitions. And you're right to question it.
I actually found in my beers, that 30 minutes are sufficient. I could go probably even lower. Sure, I need more hops, but when everything turns into late additions, you get more flavor out of it. So no problem for me. I could probably even do with a 30 minute mash in addition, loosing just a few efficiency points while shortening my brew day. I might try that one day.

I don't know if my short boiled beers last a month shorter than 60 minute beers? Doesn't really play a role for me, I drink them when they peak in flavour anyway.
 

McMullan

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I clean up, prep a sanitised FV and have lunch with at least a couple cups of tea during the boil. I have no interest in reducing my 90-min boils to save time. It's time already spent, for me. Sanitation levels are correlated with boil time, too. It would be interesting to see how long it takes for viable wort bugs to culture in wort boiled for 0, 30, 60 and 90 minutes. A less vigorous boil might help to reduce any undesirable thermal decomposition. I just see more cons than benefits with shorter boil times. I wouldn't even drop to 60-min boils. Tried it a few times and wasn't happy with the beers. Obviously, that might have had nothing to do with boil time. Just random bad luck associated with another uncontrolled factor(s), but don't tell Brulosophy that, aye? 😉
 

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When did this change?
With regard to home brewing and shorter boil times, I have found podcasts from 2005 that briefly discuss the idea of shorter boils.

So the idea of shorter boils has probably been around "at the home brew level" for a long, long time.



Based on anecdotes, it would appear that shorter boils are a useful technique for many home brewers.

It may be that home brewers don't some of the same goals as professional brewers.
 

Miraculix

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I clean up, prep a sanitised FV and have lunch with at least a couple cups of tea during the boil. I have no interest in reducing my 90-min boils to save time. It's time already spent, for me. Sanitation levels are correlated with boil time, too. It would be interesting to see how long it takes for viable wort bugs to culture in wort boiled for 0, 30, 60 and 90 minutes. A less vigorous boil might help to reduce any undesirable thermal decomposition. I just see more cons than benefits with shorter boil times. I wouldn't even drop to 60-min boils. Tried it a few times and wasn't happy with the beers. Obviously, that might have had nothing to do with boil time. Just random bad luck associated with another uncontrolled factor(s), but don't tell Brulosophy that, aye?
I don't see much that would speak for longer boils actually, if you are not after specific caramelized flavours or colour which it might impart.

After a really short boil, everything is dead, except spores. These spores will also be there after a longer boil. If you would want to remove these, you would need to either cool it down, wait till they changed from spores to "normal" cells and then boil again, or boil at a higher temperature under pressure.

DMS might be a valid reason, depending on the malt used.

More hops needed for shorter boils, definitely true.

But otherwise? I don't see anything that would really speak against it tbh.
 

McMullan

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Don't homebrew discussions about shorter boils, going back to the 00s, refer to 60-min boils? The full benefits of boiling wort, including stabilising the product, aren't necessarily promoted by very short boil times. If I used an extract kit - that's already been boiled - and had some hop extract, I might consider a very short boil.
 

McMullan

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I don't see much that would speak for longer boils actually, if you are not after specific caramelized flavours or colour which it might impart.

After a really short boil, everything is dead, except spores. These spores will also be there after a longer boil. If you would want to remove these, you would need to either cool it down, wait till they changed from spores to "normal" cells and then boil again, or boil at a higher temperature under pressure.

DMS might be a valid reason, depending on the malt used.

More hops needed for shorter boils, definitely true.

But otherwise? I don't see anything that would really speak against it tbh.
Yes, I think I want some of those flavours, too. What remains of the unwanted bugs ethanol and low pH finish off mainly. Pitch well!
 

VikeMan

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One potential benefit of short(er) boils is reduced thermal load. From a certificate course in brewing science I took from KV Leuven:

"Thermal load is the thermal stress that the mash/wort/beer endures during the whole brewing process (rate of energy transfer over the whole brewing time). Thermal load is already known for a long time as one of the factors causing flavour instability. By minimizing the heat load as much as possible throughout the malting and brewing process, several unwanted reactions (e.g. autoxidation of unsaturated fatty acids, Maillard reactions, Strecker degradation) can be limited. Also limiting the pasteurisation temperature and time (within the limits to obtain a microbiological stable product) will reduce the heat load."

Brewing is chock full of tradeoffs.
 

McMullan

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I think this is why a consensus is forming re the benefits of a less vigorous boil. I can see the 'thermal load' being more of an issue with lager beers, especially big brands. For an English cask ale, not so much. My understanding is reduced boil times for commercial brewers have been motivated more by energy savings than anything else.
 

JoeSpartaNJ

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I have been doing 30 minute boils for the last 2 years or so. When the "hazy" trend started gaining ground and the use of no boil hops became the norm, I decided to test shorter boil times. I then started doing this for all the hop forward beers, and other than the loss of a few OG points, I have not noticed any significant differences than a 60 minute boil.

For more malt forward beers (porter, stout, amber, etc.) I still do a 60 minute boil, as I think the shorter boil time robs some malt flavor.

No science behind my methods, just works for me.
 

Alan Reginato

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Bright, crystal clear beers won't be always wired with boil time. 60 min boil time.



Be-134





IMG-20220611-WA0013.jpeg IMG_20220613_151307.jpg
The second it's a different yeast, Same batch, drop like a rock in the fermenter. But did not get clear. That's for @McMullan to guess. Acid and strong orange peel, a favourite of yours. Hehehe
 
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McMullan

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Me too, with 90-min boils. I'm very happy. And all credible sources that have shaped the brewing process explain why it works for me and most brewers. For me, it's not broken, so I'm not looking for a fix based on opinions and superstitions. If it works for others, great, everyone's happy.
 

Alan Reginato

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Sorry guys, I got some issues trying to post the pictures. It's same batch but different yeasts.
 

Miraculix

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Me too, with 90-min boils. I'm very happy. And all credible sources that have shaped the brewing process explain why it works for me and most brewers. For me, it's not broken, so I'm not looking for a fix based on opinions and superstitions. If it works for others, great, everyone's happy.
I wouldn't change it either, if I wouldn't brew in the evening. But finishing before midnight, including cleaning, is just very nice for me. I like to cut corners and as long as there are no ill effects visible, I'll stay with it.

A fun thing to do would be a comparison with the same base, one boiled for 90, one boiled for 30 minutes. I would really like to know how that changes the flavour.
 
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Red over White

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Keeping the entire hotside "time" in mind may be worth considering to when comparing pro systems to the homebrew scale or homebrew to homebrew results. A 30 min infusion mash with no mashout and a 30 min boil with only the ramp time in-between vs a 2 hour step mash, mash out, ramp and boil along with whirlpool time are quite different.
 

Homebrewer20

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I've tried all, 30, 60, 90 minute boils. I do 30 minutes now, and never throw any hops in during the boil.. Every once in a while I'll do a bittering addition for 30 minutes though.
Double Whirlpool always, 1 to 2 oz of hops in each whirlpool, one at flameout, the next an hour later. Naturally cooling the wort as the whirlpools go.
I do 2 30 minute whirlpools sometimes as well to save time.
Works for west coast, and hazy styles and all you'll ever need for a good beer!
Cheers
 
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For those brewing 'hop forward' styles, The New IPA (ISBN 13: 978-0578477862) is a good starting point for links to papers and presentations.

OP is "brewing clear beer. Lager and English bitter." - and the book isn't as helpful for those styles.
 

Brooothru

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I wouldn't change it either, if I wouldn't brew in the evening. But finishing before midnight, including cleaning, is just very nice for me. I like to cut corners and as long as there are no ill effects visible, I'll stay with it.

A fun thing to do would be a comparison with the same base, one boiled for 90, one boiled for 30 minutes. I would really like to know how that changes the flavour.
I solved the "60 vs.90 minute boil" conundrum by going to 75 minute low intensity boils for both ales and lagers. As one pundent wrote, it works for me. I literally can find no difference (thus no benefit) with 90 minutes instead of 60 or less, except for possible DMS. Normalizing all boils at 75 minutes makes my brew day work flow more consistent and predictable.
 

Silver_Is_Money

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The only science which I can think of in favor of reduced boiling times is that pellet hops release their IBU's so rapidly that there is little to be gained by boiling them for more than about 45 minutes. AA for AA, and weight for weight, pellet hops deliver in ~45 minutes the IBU's of whole hops boiled for ~90 minutes.

IMHO, all commonly available algorithms for the nominally educated guesstimation of IBU's fall off a cliff as to prediction precision when one uses them in conjunction with pellet hops. Tinseth has stated that he never once tested a pellet hop, and he is also on record as having stated that "For pellet hops all bets are off.".
 

Silver_Is_Money

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I'm blatantly stealing my own quote from a post I made to a different forum here:
Chemistry Professor Christopher S. Hamilton, Ph.D, Hillsdale College gave a presentation titled "The Effect of Temperature and Alpha-Acid Concentration on Hop Utilization in Wort" at the EBC Hop Symposium in Nuremberg, Germany, in September of 2018. His presentation indicates that pellet hop utilization is realized much more quickly within the boil than for whole hops. Essentially he showed that after only about 30 to 40 minutes of boiling, a pellet hop will have delivered to the Wort as many IBU's as for a whole leaf type hop of the same AA after 60 to 90 minutes of boiling.
 

McMullan

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This is the kind of data that need to be confirmed. The idea we run with a graph is half the problem. I don't deny the predictable pattern, I've just seen it presented much steeper, by people I respect more for their integrity. Hence the need to confirm.
 

Gilbert Spinning Horse

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I clean up, prep a sanitised FV and have lunch with at least a couple cups of tea during the boil. I have no interest in reducing my 90-min boils to save time. It's time already spent, for me. Sanitation levels are correlated with boil time, too. It would be interesting to see how long it takes for viable wort bugs to culture in wort boiled for 0, 30, 60 and 90 minutes. A less vigorous boil might help to reduce any undesirable thermal decomposition. I just see more cons than benefits with shorter boil times. I wouldn't even drop to 60-min boils. Tried it a few times and wasn't happy with the beers. Obviously, that might have had nothing to do with boil time. Just random bad luck associated with another uncontrolled factor(s), but don't tell Brulosophy that, aye? 😉
I doubt boil times have anything to do with killing bugs as it's not even necessary to boil the wort to sanitize it. I regularly do no boil brews, where I give it half an hour over 72ºC.
Louis Pasteur seemed to have quite a bit of success playing about with this.
 

McMullan

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I doubt boil times have anything to do with killing bugs as it's not even necessary to boil the wort to sanitize it. I regularly do no boil brews, where I give it half an hour over 72ºC.
Louis Pasteur seemed to have quite a bit of success playing about with this.
I know more than Louis Pasteur ever did, ironically. My microscope's better too 😂
 
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This is the kind of data that need to be confirmed.
That's mentioned in the podcast.

And if there is conflicting data, feel free to bring it forward.

The idea we run with a graph is half the problem. I don't deny the predictable pattern, I've just seen it presented much steeper, by people I respect more for their integrity. Hence the need to confirm.
There are other podcasts / exBEERiments / etc where short boil batches were sent to labs for IBU analysis. The results were similar. Perhaps nothing more than additional anecdotals that match the data.



eta: Master Brewers Podcast #123 ('Tracking IBU Through the Brewing Process') is often mentioned in discussions on hops and IBUs.
 
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Silver_Is_Money

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I'm fairly certain that the EBC Hop Symposium in Nuremberg, Germany did not merely invite schmoes off the street to give IBU presentations. Professor Christopher S. Hamilton, Ph.D, of Hillsdale College, actually did the hard science and measurement, with the assistance of his Graduate Students.
 

McMullan

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German research is what it is, frankly. 🤷 Assumptions it ever represents much are just that, assumptions. Good scientific practice you'll not find. Just PR. Believe has always been a more powerful model in German research. It's not my responsibility either. So don't waste any time trolling me 🤫
 
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I don't deny the predictable pattern, I've just seen it presented much steeper, by people I respect more for their integrity.

Are you willing to share references to those sources? If so, please share them.

Me too, with 90-min boils. I'm very happy. And all credible sources that have shaped the brewing process explain why it works for me and most brewers.

Are you willing to share references to those sources? If so, please share them.
 

McMullan

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Are you willing to share references to those sources? If so, please share them.



Are you willing to share references to those sources? If so, please share them.
Brewing has been a scientific discipline for more than a century. Are you willing to read the literature?
 
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Start here. If you get stuck, ask.
We know the difference between a reference and a journal. We'll take it from here.



Let's go back for a moment to the side sub-sub-topic of pellet hops, shorter boil times, and predictive models for IBUs. There was a recent article (link) that may be of interest. Again, it's something that would need to be confirmed (perhaps with lab measured attributes, perhaps by tasting the result).

So are there other articles (journal science, citizen science, random musings) that support or challenge this data?



There's also the primary topic of lagers, English bitters, shelf stability, and boil times.
 
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