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10-21-2009, 08:44 PM   #1
Xiren
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Jun 2007
Mishawaka, Indiana
Posts: 115
Liked 1 Times on 1 Posts

I was listening to a podcast, where someone was able to use a yardstick and multiply the result by some number to get the gallons of wort in his kettle. Since the kettle dimension are different for everyones kettle, does anyone know how to figure this out?
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10-21-2009, 08:52 PM   #2
jcarson83

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Jun 2006
Springfield, MO
Posts: 928
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1 gal = .13 cubic feet. So pie r square times decimal feet for the depth. Or you could just pour in a gallon and mark it and repeat.

10-21-2009, 08:53 PM   #3
weirdboy
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May 2009
Los Angeles
Posts: 8,219
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What I do is mark my yardstick with gallon and half-gallon lines on the back.

I used math to figure out how many inches per gallon, and worked from there.

The volume of a cynlinder is the height times Pi * R^2, where R is the radius.
The only thing I had to look up was the conversion from cubic inches to gallons.

10-21-2009, 08:53 PM   #4
DRoyLenz

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Jun 2009
Chicago
Posts: 702
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This is kind of a cool idea, I think I might run these calculations and try this.

10-21-2009, 08:55 PM   #5
Walker
I use secondaries. :p

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Sep 2005
Cary, NC
Posts: 10,987
Liked 101 Times on 89 Posts

If you consider your kettle to be a simple cylinder, the volume of the liquid in the kettle would be:
<b>

</b>where "r" is the inside radius of the kettle and h is the height of the liquid in it.

If you use a yardstick, this will give you a volume in cubic inches, which you can convert to gallons with the rule:

1 gallon = 231 cubic inches

I took the cheater method and filled my kettle with a 4 gallons of water, stuck my Big Spoon in it, and marked the waver level on the spoon.

Repeat until you have a spoon that can serve as a dip-stick and tell you how much is in the kettle.
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10-21-2009, 08:57 PM   #6
uwjester

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Sep 2007
Fort Collins, CO
Posts: 688
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If you know you have a 10 gallon kettle, divide the height by 10 to find how many gallons per inch/centimeter. That way, you can measure from the top and still know. I'm all for the calculations, but this may be an easier way. My 15 gallon kettle is 15" tall, so I just know that each inch is 1 gallon.

Edit: I had the numbers backwards. They should be right now.
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10-22-2009, 01:18 AM   #7
shortyjacobs
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Aug 2009
Twin Cities, MN
Posts: 2,509
Liked 35 Times on 35 Posts

My keggle has a curved bottom. I poured in gallons of water to find out how many inches per gallon. It came out to:

2.25 inches for the first gallon
1.38 inches for every gallon thereafter....

Therefore, 6 gallons would be 2.25+1.38*5 inches.

10-22-2009, 03:38 AM   #8
Scut_Monkey

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Jan 2009
Pittsburgh, Pennsylvania
Posts: 2,656
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Yeah I do the old marked stick for my measurements. I try to limit as much math as possible during my brewday to allow for more fun (ie beer).

10-22-2009, 12:31 PM   #9
Homercidal

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Feb 2008
Reed City, MI
Posts: 31,659
Liked 5092 Times on 3443 Posts

I've been meaning to do this for a while now. Somehow it never seems to get done.
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10-22-2009, 01:40 PM   #10
springer

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Feb 2008
Wappingers falls NY
Posts: 4,743
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can't do this with a Coors keg its not a straight cylinder I had to use the old add a gallon to the HLT and mark the site glass . The keggle was easy its pretty much linear .
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