The Magical 1.2:1 Ratio for Brew Pots

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hinkensj

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Question about the "magical" height to diameter ratio for our brew kettles. A ratio of 1.2 to 1 is boasted by several retailers as the best ratio for our brew kettles. Indeed, if one checks the specifications for most brew settles available the ratio is in fact 1.2 to 1. This includes Blichmann, Spike Brewing, SS Brewing Technologies and the self-named Megabit 1.2 from Northern Brewer.

Is this magic ratio based on some "fill level" of the kettle in question? Or does it have more to do with the physics of the kettle itself. In other words, if one were boiling seven gallons of wort in a 10 gallon kettle, the pot would would have a ratio of 1.2:1, but the _liquid_ would have a different ratio. To take the example further, if one were to boil the same 7 gallons in a 30 gallon pot, the height to width ratio of the liquid would be dramatically different. (Yes, I know we don't boil 7 gallons of wort in a 30 gallon pot--it's just an example for discussion.) :)

I am thinking of upgrading to 30 gallon kettles and starting 15 gallon batches, but started to think about what happens if I were to brew 10 gallons such a set up. And could I ever do a 5 gallon test batch using 30 gallon kettles for my MLT and BK?

Thoughts?
 
The brewer makes the beer good, not the pot. Don't worry about things like that. If you think your 5 gallon batch won't be good unless you boil it in a suitable size pot, you're mistaken.

I would be concerned about the depth of the grain bed for a low OG 5 gallon batch in a MLT meant for much larger batches.
 
Pretty sure it's just more efficient to have a taller pot so there less surface area and less boil off. That's what I assume anyways.
 
It might be to keep the boil off rate reasonable. My new small batch setup has a boil off rate of ~ 0.51 g / hr and the pot is only 2 gallons. If a 10 gallon pot had the same diameter to volume ratio it would boil off a lot more than 1 gal / hr.
 
Question about the "magical" height to diameter ratio for our brew kettles. A ratio of 1.2 to 1 is boasted by several retailers as the best ratio for our brew kettles. Indeed, if one checks the specifications for most brew settles available the ratio is in fact 1.2 to 1. This includes Blichmann, Spike Brewing, SS Brewing Technologies and the self-named Megabit 1.2 from Northern Brewer.

Is this magic ratio based on some "fill level" of the kettle in question? Or does it have more to do with the physics of the kettle itself. In other words, if one were boiling seven gallons of wort in a 10 gallon kettle, the pot would would have a ratio of 1.2:1, but the _liquid_ would have a different ratio. To take the example further, if one were to boil the same 7 gallons in a 30 gallon pot, the height to width ratio of the liquid would be dramatically different. (Yes, I know we don't boil 7 gallons of wort in a 30 gallon pot--it's just an example for discussion.) :)

I am thinking of upgrading to 30 gallon kettles and starting 15 gallon batches, but started to think about what happens if I were to brew 10 gallons such a set up. And could I ever do a 5 gallon test batch using 30 gallon kettles for my MLT and BK?

Thoughts?

30 gallon is probably pushing it, but i brew 5 gallon batches in my 20 gallon just fine. With a standard 30 gallon pot that is damn wide you probably couldnt submerge a electric element under 6 gallons. 10 gallon batches should be fine. MLT should be fine as well, the only issue i have with doing 5 gallon batches is i use a Jaybird false bottom which sits an inch or two off the bottom, so there is a lot of 'dead' space under the MLT that I have to account for in my mash volume..usually just means i add another gallon or so of water to my mash to offset all the liquid under the false bottom. Not a big deal to take a gallon from the sparge, im recircing the entire time during the mash anyways so a lot of the sugar is in solution already.
 
You can brew as small as you want, just make sure you know how much you'll lose to evaporation and plan that into your recipes. I know Tasty uses the same big pot for no matter what size. I've got a 30g pot and have brewed plenty of 5g batches with it. It's just weird looking into a huge pot and seeing a couple inches of wort in it.
 
Ratio seems to be important as it pertains to surface area exposed. I got a wide pot a couple years ago based on price only and now regret it. The boil off is crazy high, now looking for something narrower.
 
I have 30 gallon spike kettles and I can do 10 gallon no problem. I wouldn't go any smaller though.. my main issue is with so much dead space in the mash tun I lose a lot of heat.. other than that no problem.
 
I bought the Update International 25 gallon kettles that are similar to the older MegaPots, about 20 inches wide and 20 inches tall. I have seem to have more boiloff than most guys with keggles. I'm doing 10 or 15 gallon batches using batch sparge, so I just increase my sparge volume to accomodate that. I suppose I buy a couple of more gallons of RO water per batch. At $0.40/gallon, it will take me a long time to spend the $100 or so I saved not buying the re-branded MegaPots.
 
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