Author Topic: Why are 60 and 90 minute boils the norm? Why not longer?  (Read 5692 times)

Online morticaixavier

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Re: Why are 60 and 90 minute boils the norm? Why not longer?
« Reply #15 on: April 26, 2012, 10:53:25 AM »
I'll use a long boil (120 min+) if I want to hit a gravity number or volume, or if I want to increase complexity via kettle caramelization (scottish, BW). I havn't really worked with pils malt much but a 90 min doesn't seem unreasonable.
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Offline kylekohlmorgen

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Re: Why are 60 and 90 minute boils the norm? Why not longer?
« Reply #16 on: April 26, 2012, 11:14:36 AM »
Martin and Keith hit it on the head - 60-90 min boil will give you all the isomerization and SMM volitization that you need - ASSUMING you keep a good, rolling boil throughout.

Urquell probably had a longer boil because of an inefficient kettle OR because using a hard boil would create hot spots and darken the wort.

At home, if you've got a good, stainless or dense aluminum brewpot and adjust your air/gas valves for an efficient burn, a good, rolling boil without hotspots is easy to maintain. In fact, most homebrewers have to cut back on the boil intensity. (Martin actually pointed out to me that I was "boiling the Be-Jesus" out of a Saison at a Big Brew a few years ago - has since been corrected)

If you use a long boil to concentrate or carmelize wort, add the bittering hops no earlier than the 90-mark. I think hops (much like over-cooked vegetables) have a dull, papery, "vegetal" flavor.
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Offline tschmidlin

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Re: Why are 60 and 90 minute boils the norm? Why not longer?
« Reply #17 on: April 27, 2012, 12:20:00 AM »
I think it is worth playing with, but I always do at least a 90 min boil with pils malt.  It really depends on your palate (and if you are entering competitions, the judges' palates).
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Offline a10t2

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Re: Why are 60 and 90 minute boils the norm? Why not longer?
« Reply #18 on: April 27, 2012, 06:19:41 AM »
This is your weekly reminder that caramelization can't happen in wort under atmospheric pressure, and that the term is "non-enzymatic browning". Now back to your regularly scheduled thread. ;D
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Offline denny

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Re: Why are 60 and 90 minute boils the norm? Why not longer?
« Reply #19 on: April 27, 2012, 08:39:54 AM »
This is your weekly reminder that caramelization can't happen in wort under atmospheric pressure, and that the term is "non-enzymatic browning". Now back to your regularly scheduled thread. ;D

+1.  I was dying to say that, but I say it so often that I was waiting for someone else to mention it!
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Online morticaixavier

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Re: Why are 60 and 90 minute boils the norm? Why not longer?
« Reply #20 on: April 27, 2012, 08:58:32 AM »
This is your weekly reminder that caramelization can't happen in wort under atmospheric pressure, and that the term is "non-enzymatic browning". Now back to your regularly scheduled thread. ;D

+1.  I was dying to say that, but I say it so often that I was waiting for someone else to mention it!

you have each earned 5 pedant points, collect 999,995 more to win this handsome tie pin. Okay, so I use a long boil to acheive greater malt complexity via 'non-enzymatic browning'. sure tastes like caramelization.

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Offline bo

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Re: Why are 60 and 90 minute boils the norm? Why not longer?
« Reply #21 on: April 27, 2012, 09:09:41 AM »
This is your weekly reminder that caramelization can't happen in wort under atmospheric pressure, and that the term is "non-enzymatic browning". Now back to your regularly scheduled thread. ;D

+1.  I was dying to say that, but I say it so often that I was waiting for someone else to mention it!

you have each earned 5 pedant points, collect 999,995 more to win this handsome tie pin. Okay, so I use a long boil to acheive greater malt complexity via 'non-enzymatic browning'. sure tastes like caramelization.

You can get some carmelization with direct fired kettles. Here's a quote from Brewing Science and Practice:

"Local overheating, as was common with older, direct-fired coppers, can also cause burn-on and carmelization of wort sugars and copper adjuncts…"

Can it be done with SS or aluminum kettles? Not sure with SS, but seems possible with aluminum.

Offline nateo

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Re: Why are 60 and 90 minute boils the norm? Why not longer?
« Reply #22 on: April 27, 2012, 10:13:49 AM »
If I find little spots of burnt wort at the bottom of my kettle (because of hot spots) could I reasonably assume it caramelized before it burned? It's an aluminum pot, and I'll typically find a couple spots about as big as a quarter that are burnt.
« Last Edit: April 27, 2012, 10:15:29 AM by nateo »
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Offline euge

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Re: Why are 60 and 90 minute boils the norm? Why not longer?
« Reply #23 on: April 28, 2012, 10:18:21 AM »
Years ago I was finding some "spots" that I had scrub off. They weren't burnt but it was obvious to me the heat was too high.

If you are getting burnt spots in you kettle back off on your flame a bit. You'll still have a great boil. Don't worry.
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Offline thomasbarnes

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Re: Why are 60 and 90 minute boils the norm? Why not longer?
« Reply #24 on: May 11, 2012, 06:48:17 PM »
I think there are a few reasons.  First is wort darking and caramelization.  The second is that the isomerization activity of alpha acids plateau's completely by 90 minutes.  Third is that the benefit of SMM volatilization drops off appreciably as the malt's reserve of SMM is relatively exhausted around 60 minutes for pale malt and 90 minutes for pils malt.

The pro-brewer/scientific literature I've seen indicates that AA utilization peaks at ~2 hours, but a 90 minute boil is generally good enough. A 2-hour boil might be needed if you're really trying to pull every alpha acid molecule you can out of the beer in a high gravity wort.

Other than that, spot on.

Big pro-brewers hate long boils both because of energy costs and because time is money - especially for big brewers which might be brewing 4-5 batches per day. They have all sorts of tricks to minimize energy usage and speed up wort boiling. One of the coolest, but trickiest, is brewing the beer under a slight pressurization. AA Isomeration is optimized at something like 215-220 *F, but the danger is that if you get your wort much hotter than that, AA start to degrade :O

Offline mabrungard

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Re: Why are 60 and 90 minute boils the norm? Why not longer?
« Reply #25 on: May 12, 2012, 05:57:27 AM »

The pro-brewer/scientific literature I've seen indicates that AA utilization peaks at ~2 hours, but a 90 minute boil is generally good enough. A 2-hour boil might be needed if you're really trying to pull every alpha acid molecule you can out of the beer in a high gravity wort.

Other than that, spot on.

Big pro-brewers hate long boils both because of energy costs and because time is money - especially for big brewers which might be brewing 4-5 batches per day. They have all sorts of tricks to minimize energy usage and speed up wort boiling. One of the coolest, but trickiest, is brewing the beer under a slight pressurization. AA Isomeration is optimized at something like 215-220 *F, but the danger is that if you get your wort much hotter than that, AA start to degrade :O

I look forward to seeing that data.  The isomerization test results from Malowicki and Shellhammer indicate that 90 minutes is the peak.  They found a very slight drop off at 120 minutes.  They also looked at pressurized boiling and established a correlation to energy input and isomerization rate.
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Offline majorvices

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Re: Why are 60 and 90 minute boils the norm? Why not longer?
« Reply #26 on: May 12, 2012, 06:02:20 AM »
What it all boils down to is wait for the wort to foam up and drop back into itself. That's the hot break. I won't add hops until then. Boiling purposefully longer than that isn't necessary IMO. Unless you have a specific reason like a boil-down like I did with the BW. That was a triple sparge and a large grain-bill and would have produced 20 gallons of regular beer.

I always wait until I actually see hot break in the kettle (egg drop soup). My understanding is you want those proteins to coagulate before you add the hops.
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Offline nateo

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Re: Why are 60 and 90 minute boils the norm? Why not longer?
« Reply #27 on: May 12, 2012, 06:18:09 AM »
I always wait until I actually see hot break in the kettle (egg drop soup). My understanding is you want those proteins to coagulate before you add the hops.

In Warner's Wheat book, he actually says to add half the bittering hops at -120min and half at -60min, IIRC. The hop bits help coagulate the proteins to provide better hot break.

FWIW the weizen I brewed with a 120min boil, while noticeably clearer going into the fermentor, was not clear in the bottle.
« Last Edit: May 12, 2012, 06:23:03 AM by nateo »
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Offline rgnlkngtylrbmbstk

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Re: Why are 60 and 90 minute boils the norm? Why not longer?
« Reply #28 on: May 13, 2012, 05:56:35 PM »
I didn't peruse the entire thread, but if it hasn't been mentioned, somewhere around 2 hours into a boil you run the risk of redissolving the hot break. That may be a good thing for long-aged brews like the big Scottish beers, but in general it seems like fodder for infection.

Offline The Professor

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Re: Why are 60 and 90 minute boils the norm? Why not longer?
« Reply #29 on: May 13, 2012, 06:19:30 PM »
... Is there a reason I shouldn't boil all my worts for 120min?

The short answer...because in most cases you simply don't need to.
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