Author Topic: Volume in my Kettle  (Read 838 times)

Offline 69franx

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Volume in my Kettle
« on: May 14, 2015, 08:52:24 PM »
So some googling tells me the volume surrounded by a cylinder = pi*r2*H. When I plug manufacturer's specs for my kettle into this equation, I get roughly 3.14*64*19.2 from the formula here: http://www.smartconversion.com/unit_calculation/Volume_of_a_Cylinder.aspx
and this says it equals 16.7gallons in my kettle. My main issue is that when I measure the interior dimensions of the kettle, I get a radius of 7.25" and total height of let's call it 18 7/8". Plugging these measurements into the formula yields a volume of just under 13.5 gallons. This kettle was marketed through kickstarter as a 15 gallon kettle, so I am wondering if my math is off somewhere. I have weighed water by the gallon (8.35#/gallon) as I have filled the kettle with strike water and the volume never matches the manufacturer's etchings on the inside. My measurements were made with what I take to be an accurate tape measure. the reason this all matters is that this weekend, I have my first 10 gallon batch planned that will require 12.5 boil volume or adjust with top off water. If I actually have the 16.7 gallons, I am not concerned, but if I only have roughly 13.5-14 gallons inside, I am very concerned. can anyone help me trouble shoot the math to ease my mind? I know Mark had a formula posted in a thread somewhere that would help me here, but it was not specifically a kettle volume thread, so I'm having trouble narrowing down search results. Very long winded I know, but can anyone help me?
Frank L.
Fermenting: Ringler Pilsner (thanx Ron)
Conditioning: BVIP (thanx Denny)
In keg: Traquair House Clone (Skotrat style)
In the works:  Czech Dark Lager, American Pale Ale

Offline Wort-H.O.G.

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Re: Volume in my Kettle
« Reply #1 on: May 14, 2015, 11:10:28 PM »
So some googling tells me the volume surrounded by a cylinder = pi*r2*H. When I plug manufacturer's specs for my kettle into this equation, I get roughly 3.14*64*19.2 from the formula here: http://www.smartconversion.com/unit_calculation/Volume_of_a_Cylinder.aspx
and this says it equals 16.7gallons in my kettle. My main issue is that when I measure the interior dimensions of the kettle, I get a radius of 7.25" and total height of let's call it 18 7/8". Plugging these measurements into the formula yields a volume of just under 13.5 gallons. This kettle was marketed through kickstarter as a 15 gallon kettle, so I am wondering if my math is off somewhere. I have weighed water by the gallon (8.35#/gallon) as I have filled the kettle with strike water and the volume never matches the manufacturer's etchings on the inside. My measurements were made with what I take to be an accurate tape measure. the reason this all matters is that this weekend, I have my first 10 gallon batch planned that will require 12.5 boil volume or adjust with top off water. If I actually have the 16.7 gallons, I am not concerned, but if I only have roughly 13.5-14 gallons inside, I am very concerned. can anyone help me trouble shoot the math to ease my mind? I know Mark had a formula posted in a thread somewhere that would help me here, but it was not specifically a kettle volume thread, so I'm having trouble narrowing down search results. Very long winded I know, but can anyone help me?

The radius is 7.25" (14.5" divided by two)
The radius squared is 7.25" X 7.25" which equals 52.56
So now we have 3.14 X 52.65 X 18.875 (height) = 3120 (this is the total cubic inches in the pot)

3120 / 231 = 13.5 (the number of gallons the pot will hold)


your math seems correct if your measurements are correct.
Ken- Chagrin Falls, OH
CPT, U.S.Army
https://www.facebook.com/pages/Harveys-Brewhaus/405092862905115

http://braukaiser.com/wiki/index.php?title=The_Science_of_Mashing

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Offline 69franx

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Re: Volume in my Kettle
« Reply #2 on: May 14, 2015, 11:19:26 PM »
Thanks ken, now I'm pissed at the manufacturer again
Now that I see you run the math, I realize I'm the dumb#$%. Half of my diameter is 7.75, not 7.25. And to think I think of myself as a math guy! Plugging that into the formula gives me a volume of roughly 15.42 gallons, so its as advertised. Think with a little ferm cap I will still be good to go as long as I keep a watchful eye on it. Thanks again.
« Last Edit: May 14, 2015, 11:31:04 PM by 69franx »
Frank L.
Fermenting: Ringler Pilsner (thanx Ron)
Conditioning: BVIP (thanx Denny)
In keg: Traquair House Clone (Skotrat style)
In the works:  Czech Dark Lager, American Pale Ale

Offline Wort-H.O.G.

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Re: Volume in my Kettle
« Reply #3 on: May 15, 2015, 12:18:13 AM »

Thanks ken, now I'm pissed at the manufacturer again
Now that I see you run the math, I realize I'm the dumb#$%. Half of my diameter is 7.75, not 7.25. And to think I think of myself as a math guy! Plugging that into the formula gives me a volume of roughly 15.42 gallons, so its as advertised. Think with a little ferm cap I will still be good to go as long as I keep a watchful eye on it. Thanks again.

Haha! It happens. Glad you figured it out and can breathe now Frank.


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Ken- Chagrin Falls, OH
CPT, U.S.Army
https://www.facebook.com/pages/Harveys-Brewhaus/405092862905115

http://braukaiser.com/wiki/index.php?title=The_Science_of_Mashing

Serving:        In Process:
Vienna IPA          O'Fest
Dort
Mead                 
Cider                         
Ger'merican Blonde
Amber Ale
Next:
Ger Pils
O'Fest