Author Topic: Boil Length  (Read 2194 times)

Offline hopfenundmalz

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Re: Boil Length
« Reply #30 on: July 29, 2019, 12:13:53 PM »
Like BrewBama I find the key is a gentler boil.

I go 60 minutes too, very very gentle.  Just a bare simmer, enough to give good circulation, lid on except for a mere crack, until the last 15 minutes.  Then the lid comes off and the heat goes up some to keep it circulating well.

But the index of thermal loading is really evaporation I think.  The difference I've seen in wort quality between under 60, gentle, and about 6% evaporation, and any process giving 10% or more evaporation, is night and day.  And the impact on beer quality and stability tracks also.  Advantages in flavor and aroma, foam, all sorts of things.

So boil length isn't the real thing, it's total thermal loading. Think the area under the time/temperature curve on a graph.  You do need some time to utilize hops, and you need good circulation to coagulate protein.

Martin Brungard did a presentation on boiling at the 2018 HomebrewCon IIRC. Robert's post is pretty much what Martin said.

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Re: Boil Length
« Reply #31 on: July 29, 2019, 12:37:18 PM »
Like BrewBama I find the key is a gentler boil.

I go 60 minutes too, very very gentle.  Just a bare simmer, enough to give good circulation, lid on except for a mere crack, until the last 15 minutes.  Then the lid comes off and the heat goes up some to keep it circulating well.

But the index of thermal loading is really evaporation I think.  The difference I've seen in wort quality between under 60, gentle, and about 6% evaporation, and any process giving 10% or more evaporation, is night and day.  And the impact on beer quality and stability tracks also.  Advantages in flavor and aroma, foam, all sorts of things.

So boil length isn't the real thing, it's total thermal loading. Think the area under the time/temperature curve on a graph.  You do need some time to utilize hops, and you need good circulation to coagulate protein.

Martin Brungard did a presentation on boiling at the 2018 HomebrewCon IIRC. Robert's post is pretty much what Martin said.

And just recently, Martin put that information into an article in the May/June 2019 Zymurgy.  Good read.
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Offline goose

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Re: Boil Length
« Reply #32 on: July 29, 2019, 01:17:50 PM »
Like BrewBama I find the key is a gentler boil.

I go 60 minutes too, very very gentle.  Just a bare simmer, enough to give good circulation, lid on except for a mere crack, until the last 15 minutes.  Then the lid comes off and the heat goes up some to keep it circulating well.

But the index of thermal loading is really evaporation I think.  The difference I've seen in wort quality between under 60, gentle, and about 6% evaporation, and any process giving 10% or more evaporation, is night and day.  And the impact on beer quality and stability tracks also.  Advantages in flavor and aroma, foam, all sorts of things.

So boil length isn't the real thing, it's total thermal loading. Think the area under the time/temperature curve on a graph.  You do need some time to utilize hops, and you need good circulation to coagulate protein.

I have read that a good "rolling" boil leads to better hop utilization.  However, I do not notice a lot of difference with a bit more gentle boil when I am using whole cone hops.  The only thing that sometimes concerns me when using pellets (I have switched to them in a lot of cases because of better availability) in a big hop bag is that I want the hops to be constantly moving around in the bag during the boil rather than forming a big tight ball of goo.  A bit more aggressive boil gives me piece of mind on that issue as does using a large hop bag.  Full disclosure, I do not whirlpool with my brew system.  I have a false bottom and extract the wort from the center of the kettle when chilling.  i might modify that in the future.

Based on the discussions in this thread and Martin's article, I have reduced my boil times to 60 minutes from originally 90 and add the bittering addition 10 minutes into the boil.  The only beers that get boiled for 120 minutes are my Barleywine, my RIS and my Wee Heavy.  Gets me finished with the brew day a bit sooner.
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Offline denny

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Re: Boil Length
« Reply #33 on: July 30, 2019, 02:19:09 PM »
Boiled under normal pressure, the boiling time of light beer is generally controlled at 1.5-2 hours, and the concentrated beer is extended for a prolonged period of time; when boiled under pressure, the boiling time can be shortened by about half.

What about not boiling under pressure?
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Offline kgs

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Re: Boil Length
« Reply #34 on: July 31, 2019, 01:58:51 PM »

The only thing that sometimes concerns me when using pellets (I have switched to them in a lot of cases because of better availability) in a big hop bag is that I want the hops to be constantly moving around in the bag during the boil rather than forming a big tight ball of goo.  A bit more aggressive boil gives me piece of mind on that issue as does using a large hop bag. 


A year or so back, in a conversation about hop spiders with a homebrewing friend, I coined the term, "turbulation," to describe this, as in, "You need a bag large enough to encourage good turbulation." He knew exactly what I meant!
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Offline caripco

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Re: Boil Length
« Reply #35 on: August 24, 2019, 03:51:12 PM »
I am surprised I haven't seen any mention of boil temperature in this discussion. A pro brewer once told me that most breweries in our area boil for 90 minutes due to the lower temperature. We are at about 5300 ft elevation and wort boils at about 202 degrees F. The idea is that a longer time is needed to boil off DMS at a lower temperature, but I don't know if there is any science to back this up. Anyone know?

Offline mabrungard

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Re: Boil Length
« Reply #36 on: August 24, 2019, 04:03:43 PM »
The Boiling article in Zymurgy does cover the effects of high elevation. Longer boiling time can be necessary in that case.
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