Author Topic: Evaporation and finished volume  (Read 703 times)

Offline cheba420

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Evaporation and finished volume
« on: October 05, 2010, 06:14:16 PM »
Hoping to get some help out on something thats been frustrating me for a while. Heres the set up. I always pull 6.5-7 G out of my mash tun. I use a 7.5 G converted keg to boil in and a propane burner for heat. I keep my gas on just enough to keep the top of the wort rolling yet I'm losing a ton of volume in my brew day.

By the time I cool my wort and get it into the fermenter end up with 4.25 to 4.5 G of wort in the carboy. I know I'm losing some of that to the cold break that I leave behind when I chill, but 2.5 gallons lost in a one hour boil and chill?

Should I just relax and be happy with 4.5 gallons of beer or should I strive for the 5 gallon batch? I feel I'm being wasteful by not getting the yield I should get. It definitely changes the economics of the whole deal as well.

Any advice on how to get more beer from your beer?

Matt
Mesa, AZ.
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Offline tschmidlin

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Re: Evaporation and finished volume
« Reply #1 on: October 05, 2010, 09:17:38 PM »
If it's one of those squat pony kegs, that's a lot of surface area so you could lose a lot that way.  Some of the losses will be shrinkage from chilling too.

A few questions:
Is the beer in the carboy the right SG, or is it high?  If the SG is high that indicates you're boiling too much off for your recipe, if the SG is right then it points to losses between the boil and fermenter.  Have you calculated your efficiency?

You have some options . . . add boiled/chilled water to the fermenter to increase the volume and thin the beer out a bit.  Or modify your kettle to leave less behind after chilling.  Or further reduce the strength of the boil so you don't lose as much (not a great option from the description of your boil).
Tom Schmidlin

Offline euge

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Re: Evaporation and finished volume
« Reply #2 on: October 05, 2010, 10:09:46 PM »
I think maybe a bigger kettle so you can use more water. Evaporation is real. So is absorption for grain and hop material. For me it's about 2 or more gallons per hour evaporation. And as previously stated the wort expands as it gets hot and shrinks back down as it cools. Lot's of stuff to keep track of.

If you could compensate, which your kettle prevents you from doing, this problem would vanish. BTW, how big is the mash tun?
The first principle is that you must not fool yourself, and you are the easiest person to fool. -Richard P. Feynman

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Offline dzlater

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Re: Evaporation and finished volume
« Reply #3 on: October 06, 2010, 03:53:39 AM »
I don't know if it's the "correct" way or how much effect it has on the beer.
If I am reaching the limits of my kettle I will some times set a side a quart or two of wort
and add it back into the kettle after some volume has boiled off.
Dan S. from NJ

Offline denny

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Re: Evaporation and finished volume
« Reply #4 on: October 06, 2010, 09:01:10 AM »
Figure out how much you lose and compensate by starting with more wort.  I lose 1.5 gal./hr. by boiling, and figure on losing 12 oz. for every oz. of whole hops I use.  Works out pretty accurately for me.
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Offline cheba420

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Re: Evaporation and finished volume
« Reply #5 on: October 06, 2010, 09:14:00 AM »
Thanks, Gentlemen. I see two issues that I can start to work around. 1. Start with more wort in the kettle. I'm guessing I should never start with less than 7 gallons of I'm making a 5 gallon batch. I've been pulling 6.5-7. I will just always go for 7.Q: If I keep pulling more volume out of my mash tun, wont I start messing with PH and tannins and whatnot? How much can you pull before you start getting harsh flavors. Q2: So if I do a 90 minute boil I should start w/ 8 gallons???
2. I need to get more out of my kettle. I typically leave a lot behind in the kettle because it is all cloudy with cold break. I know I can get more wort out but is moving too much of the cold break a bad thing? I've read pros and cons. Just hate coming up short and wasting what could be good beer.

To answer your questions:
tschmidlin- Yes, its one of the squat Pony kegs. I have a full size keg that is cut and ready to go. I'll probably use that one starting with this weekend's brew.

euge- I'm using a keg for my mash tun as well. I have a false bottom and I insulate with some blankets. It holds the temp pretty steady and is easy to use.

Thanks again. I appreciate the tips!
Matt
Mesa, AZ.
#197645

On Tap: Vanilla Porter, Belgian Blonde, Saison, Black IPA, Punkin Porter
Primary: Pale 31 Clone, Raspberry Cider
Secondary: Vanilla Porter
Conditioning: Brett IPA
Bottles:Mosaic Wheat
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Offline cheba420

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Re: Evaporation and finished volume
« Reply #6 on: October 06, 2010, 09:20:22 AM »
Thanks, Denny. I'll watch those hops too!
Matt
Mesa, AZ.
#197645

On Tap: Vanilla Porter, Belgian Blonde, Saison, Black IPA, Punkin Porter
Primary: Pale 31 Clone, Raspberry Cider
Secondary: Vanilla Porter
Conditioning: Brett IPA
Bottles:Mosaic Wheat
On Deck: Flanders Red, Berliner weisse, Punkin Saison, Saison Brett

Offline tschmidlin

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Re: Evaporation and finished volume
« Reply #7 on: October 06, 2010, 09:38:39 AM »
You can generally draw wort until the SG drops to about 1.010.  It's kind of a pain to measure if you don't have a refractometer, but you can always batch sparge like Denny does, that should help avoid any tannin extraction.  Follow the link in his sig.

For a 90 minute boil you should just add more as you go, either wort or water.  Or you can add water to the fermenter to top it up.  Or you can adjust your recipe to expect less in the fermenter.

Re: the cold break, I use a CFC so the whole cold break ends up in my carboys.  No problem.  YMMV
Tom Schmidlin

Offline cheba420

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Re: Evaporation and finished volume
« Reply #8 on: October 06, 2010, 10:12:17 AM »
Thanks, Tom. I've been batch sparging since I went AG. Definitely seems easier than fly sparging. I'm all about making the brew day a little easier!

Been brewing for a few years now but kinda on my own. Should have jumped onto this board a long time ago. Thanks for all the help and support!
Matt
Mesa, AZ.
#197645

On Tap: Vanilla Porter, Belgian Blonde, Saison, Black IPA, Punkin Porter
Primary: Pale 31 Clone, Raspberry Cider
Secondary: Vanilla Porter
Conditioning: Brett IPA
Bottles:Mosaic Wheat
On Deck: Flanders Red, Berliner weisse, Punkin Saison, Saison Brett

Offline tschmidlin

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Re: Evaporation and finished volume
« Reply #9 on: October 06, 2010, 10:29:43 AM »
A long time ago this board didn't exist!  Welcome  :)

If you feel like joining a local club, you can try to find one here:
http://www.homebrewersassociation.org/pages/directories/find-a-club
Tom Schmidlin