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Date: 07 Nov 2006 17:26:52
From: MattMika
Subject: Volume after boil?
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I brewed my first batch in about a year last night and had a problem.
My promash session said I needed 3.54gal dough-in and 7 gal sparge
which would yield me just under 9gals of wort. I cant remember the
exact numbers but grain absorption was at about 1.6gal and evaporation
rate was at 15%/hr.
I hit volume right on the head and the runnings were still at 1.020
until the very end if my temperature conversions were correct(I assume
the SG calculator still works on wort around 120F?).
Anyway after a 90 min boil it was 2:30am and my volume was still at
6.5gal. I was tired and since the beer originally was supposed to come
out at 1.073 I said to hell with it, I'm done. I adjusted my recipe to
6.5gal and I had hit the new 75% efficiency right on the dot, 1.056.
I boiled off approx. 2.5gal. I assume inpatience was my problem and
that I should have boiled off just under 4gals right?
Anyone know an accurate evaporation rate for the Rockies? Im at
5280ft.-Denver. How about grain absorption? Is 1.6gal about right for
13.5lbs of grain?
TIA
Matt Mika
"These animals evacuate ethyl alcohol from their bowels and carbon dioxide from their urinary organs. Thus, one can observe how a specially lighter fluid is exuded from the anus and rises vertically whereas a stream of carbon dioxide is ejected at very short intervals from enormously long genitales."
Justus Freiherr von Liebig - 1839
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Date: 07 Nov 2006 22:13:19
From: David M. Taylor
Subject: Re: Volume after boil?
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"MattMika" <mattmika@hotmail.com > wrote in message
news:2062l293b9kvis571ssj67l1t7nei2dqop@4ax.com...
>I brewed my first batch in about a year last night and had a problem.
>
> My promash session said I needed 3.54gal dough-in and 7 gal sparge
> which would yield me just under 9gals of wort. I cant remember the
> exact numbers but grain absorption was at about 1.6gal and evaporation
> rate was at 15%/hr.
>
> I hit volume right on the head and the runnings were still at 1.020
> until the very end if my temperature conversions were correct(I assume
> the SG calculator still works on wort around 120F?).
>
> Anyway after a 90 min boil it was 2:30am and my volume was still at
> 6.5gal. I was tired and since the beer originally was supposed to come
> out at 1.073 I said to hell with it, I'm done. I adjusted my recipe to
> 6.5gal and I had hit the new 75% efficiency right on the dot, 1.056.
>
> I boiled off approx. 2.5gal. I assume inpatience was my problem and
> that I should have boiled off just under 4gals right?
>
> Anyone know an accurate evaporation rate for the Rockies? Im at
> 5280ft.-Denver. How about grain absorption? Is 1.6gal about right for
> 13.5lbs of grain?
> TIA
> Matt Mika
Looks to me like Promash (or your use of it) was a bit off. By my quick
calculations, it looks like 4.8 gallons would have been sufficient for a
sparge, though at the expense of some efficiency. I typically only expect
to get around 60% efficiency for a high gravity brew such as yours at 1.073.
It's really not fair to expect mid-70s for efficiency for high gravity
brews, IMHO, it just takes too much water to rinse all those grains of all
the sugars. So, it's no wonder you're frustrated, you expected reasonably
high efficiency, which you got, but you had to boil off an extra 2 gallons,
which will certainly take a very long time to do, no matter what your
evaporation rate.
Next time, simply expect in advance to get a lower efficiency for higher
gravity brews, and make sure you calculate your sparge volume correctly. I
use a custom spreadsheet for volume calculations that is based on guidance
from Ray Daniels' Designing Great Beers (excellent book). Works like a
charm. Email me privately if you want a copy of my spreadsheet.
I don't know much about brewing in the Rockies, but I'd expect more water
loss more quickly due to the lower boiling temperature, but less hop
utilization and protein coagulation. You win some, you lose some. And as
far as I know, grain absorption is pretty constant at about 0.1 gallons
water per 1 pound grain, regardless of where you are. 1.6 gallons for 13.5
lb grain seems just about right.
--
Dave
"Fill your cup with whatever bitter brew you're drinking." -- Brad Paisley
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Date: 07 Nov 2006 21:44:04
From: Wayne
Subject: Re: Volume after boil?
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MattMika wrote:
> Anyone know an accurate evaporation rate for the Rockies? Im at
> 5280ft.-Denver. How about grain absorption? Is 1.6gal about right for
> 13.5lbs of grain?
While altitude does play somewhat a factor in the evaporation rate, it's
mostly the kettle geometry and the strength of the boil that determine
the rate. Looks like your boiloff rate is 1.7 gal/hour, which is in the
normal range. As the amount of wort you boil may vary, you should use
the gal/hr figure rather than a percentage. As long as you use the same
pot, this figure should not change much.
I normally figure grain absorption at a pint per pound though I think
the actual figure is slightly higher. A pint per pound is easier to
figure in your head and is close enough for what we do. In this case we
are talking 13.5 pints (13.5/8=1.6875 gallons) so your figure is pretty
close.
Wayne
Bugeater Brewing Company
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Date: 08 Nov 2006 16:42:16
From: John 'Shaggy' Kolesar
Subject: Re: Volume after boil?
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On Tue, 07 Nov 2006 17:26:52 -0700, <mattmika@hotmail.com > wrote:
> I boiled off approx. 2.5gal. I assume inpatience was my problem and
> that I should have boiled off just under 4gals right?
Yeah, in order to get what the recipe said you would have needed to keep
boiling. Collecting almost 9 gallons for a 5 gallon batch is a lot though.
It doesn't surprise me that you would have to boil that forever. An
easier way is to bump up your grain bill some and collect less. That way
you don't have to boil for nearly as long. It'll cost you an extra dollar
or two in grain, but will save you several hours of sitting around watching
your kettle.
John.
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