Author Topic: Does boil rate matter?  (Read 686 times)

Offline scottdj

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Does boil rate matter?
« on: October 20, 2018, 02:47:04 PM »
When i do my boil, most of the time i'm doing it on my gas range - which has a limited BTU output.  It works ok, it just takes a while.  Sometime's i'll go outside and use a blichmann burner - which obviously has a MUCH higher BTU output - and as such, the boil time (time to reach temp, recover to temp after ingredients are added, etc) is far shorter than when i do it on my range.

My question is - does the energy input (and hence the boil duration) - matter?  If so, why, and what specifically is going on in a lower energy boil (longer boil) vs a higher energy (shorter) boil?

Thanks!

Offline denny

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Re: Does boil rate matter?
« Reply #1 on: October 20, 2018, 02:58:00 PM »
Technically, you're probably better off with a low boil than a high one.  Practically, I don't think it makes a lot of difference.
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Offline Robert

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Re: Does boil rate matter?
« Reply #2 on: October 20, 2018, 03:37:44 PM »
It isn't so much time as thermal loading; picture it as the area under a time/temperature curve. 

With an all-grain wort it can make a real difference.  There you want a short, low-intensity boil with less than 10% total evaporation (a good indicator,)  just enough circulation to achieve a good break and hop utilization.   More thermal stress will lead to effects such as the excessive breakdown of proteins and other substances resulting in a much duller, less fresh malt flavor,  the development of off flavors,  reduced capacity for producing and holding foam, and more rapid staling of the beer. 

But Denny's absolutely right at least as regards an extract wort.  Most of that damage has potentially already been done in the production of the extract, so you won't make a lot of difference either way.   That said, extract doesn't need any more boiling than your hop schedule requires because there's not much of a break to achieve, so no need to use extra fuel; do whatever is most efficient if that's a concern, or whatever is most convenient .
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Offline mabrungard

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Re: Does boil rate matter?
« Reply #3 on: October 20, 2018, 03:53:09 PM »
While researching that presentation on Wort Boiling, I came across an Institute of Brewing and Distilling journal article that stated that they produced beer via a boil with only 2% evaporation loss. They said it tasted fine. Since they didn't identify what malts they used, I'm less confident that brewers can actually get by with that little evaporation. Most pro's that produce good products apparently evaporate about 4% to 8%.

I'm trying to limit my loss to about 8% and I do brew some beers with high pils malt content. The main thing that brewers need to concentrate on is the circulation of wort within their kettle. You actually don't want the kettle centered on your burner. Having the burner offset slightly to one side of the kettle will help promote a better rolling action for the wort.

A volcanic boil is not necessary. If there is ANY evidence that the wort is boiling, its as hot as its going to get and all the chemical reactions that we rely on will occur at the same rate. But you probably do need some heat input in order to produce the rolling action.
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Offline scottdj

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Re: Does boil rate matter?
« Reply #4 on: October 20, 2018, 06:20:49 PM »
Interesting stuff - thanks for the insight folks.  I also ran across this which is interesting:

http://brulosophy.com/2017/05/29/boil-vigor-weak-vs-strong-exbeeriment-results/

Offline Robert

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Re: Does boil rate matter?
« Reply #5 on: October 20, 2018, 06:41:08 PM »
Martin, FWIW:  I got my total evaporation down to 4% over 45 minutes at one point.  I found that seemed  to introduce some problems, like insufficient protein coagulation which I think contributed to problems with clarity and foam, and the flavor seemed not to be improved at all over 6-8%.   Small, small sample set, to be sure.  But I've got it back up to near 8% in 60 minutes and that seems to be the Goldilocks point for me.  Those super low commercial rates must rely on processes we can't replicate.  The magic is still in heating the kettle asymmetrically!
« Last Edit: October 20, 2018, 06:46:55 PM by Robert »
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Offline BrewBama

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Re: Does boil rate matter?
« Reply #6 on: October 20, 2018, 07:11:23 PM »
I also experimented with 45 min vs 60 min boil.  I have since gone back to 60 min but less vigor and remain right at 10% boil off.

The induction plate seems to roll the wort (not sure why) so offsetting doesn’t seem required on my setup.


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Offline ynotbrusum

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Re: Does boil rate matter?
« Reply #7 on: October 24, 2018, 06:19:57 PM »
I have an electric element (ripple 5500 ULWD) and it seems to be able to maintain a soft roll at about 33% of total output capacity, after I reach the boil, with the lid very slightly and partially off (a sliver of a moon exposed).  My boil off is around a gallon - starting typically with 12 gallons of wort collected.  I much prefer this approach, but will take the lid off entirely for the last 10 minutes of the boil and "kick it up a bit" for pilsner malts to drive off DMS remaining.

One of these days I will listen to Martin's 2018 presentation at HBC for more details on his approach.
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Offline mabrungard

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Re: Does boil rate matter?
« Reply #8 on: October 25, 2018, 01:23:02 AM »
One of these days I will listen to Martin's 2018 presentation at HBC for more details on his approach.

Sadly, the personnel at the Portland Convention were quite incompetent. The audio portion for most of my presentation was not recorded. Its almost worthless to watch me flap my gums since I firmly believe in presenting only the highlights of my presentation on the slides and its my words that convey the real essence of the presentation.
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Offline ynotbrusum

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Re: Does boil rate matter?
« Reply #9 on: October 25, 2018, 08:43:45 PM »
What a bummer, Martin.  After all your work in preparing for this....
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Offline riceral

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Re: Does boil rate matter?
« Reply #10 on: October 25, 2018, 08:45:32 PM »
I was fortunate enough to attend your talk. One of the best talks I attended in Portland.

Sorry for those who didn't get a chance to hear it and missed it.
« Last Edit: October 25, 2018, 11:02:31 PM by riceral »
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Offline Robert

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Re: Does boil rate matter?
« Reply #11 on: October 25, 2018, 09:46:25 PM »
I think I've asked before, but, any chance the content could be made available otherwise someday?  Maybe a Zymurgy article?
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Offline mabrungard

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Re: Does boil rate matter?
« Reply #12 on: October 26, 2018, 11:58:11 AM »
I think I've asked before, but, any chance the content could be made available otherwise someday?  Maybe a Zymurgy article?

The article was already drafted before the presentation. However, in preparing and presenting at the conference, I saw other elements that need to be in the article. I'm working on the revision now. It will show up in Zymurgy some day.
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Offline Robert

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Re: Does boil rate matter?
« Reply #13 on: October 26, 2018, 12:15:00 PM »
I think I've asked before, but, any chance the content could be made available otherwise someday?  Maybe a Zymurgy article?

The article was already drafted before the presentation. However, in preparing and presenting at the conference, I saw other elements that need to be in the article. I'm working on the revision now. It will show up in Zymurgy some day.
Fantastic!
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Offline Wilbur

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Re: Does boil rate matter?
« Reply #14 on: October 26, 2018, 02:34:07 PM »


The magic is still in heating the kettle asymmetrically!

And this is to get wort movement with a lower boil intensity?