Have 20 gal kettles? Are there fermenters for this size?

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Well-Known Member
Dec 4, 2016
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HI, looking for advice.
I acquired Anvil's 20 gal kettles to have a three vessel system because I thought the size was manageable but now I'm finding out the rough way that there's no 20 gal size fermenters of any kind on the market, so it seems I either set for the 14 gal or 60 Liter fermenters and use the kettles at less than their capacity or go straight to 120 liters or 1 barrel fermenters which are clearly oversized for my kettles.

I'm quite bummed. Do anyone else uses 20 gal kettles? How do you manage fermentation other than 5 gal carboys?


Progressive Brewing
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Jan 9, 2013
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Pasadena, MD
Well, a 20 gallon kettle is perfect for making 15 gallons of wort. ;)
There are plenty of fermenters in the 15-16 gallon size.

Why can't you make 20 gallons of wort in a 20 gallon kettle?
  1. First you need an inch or 2 of headspace in your boil kettle to prevent splashing and boil overs.
  2. Then there's another 4% volume increase, due to expansion at boiling temps.
  3. So you can fit around 17-18 gallons of wort into that kettle.
  4. Since you're boiling the wort (lautered from the mash tun) for an hour, you'll be evaporating at least 1.5-2 gallons of water (possibly more), condensing your wort at the same time. That's all par for the course.
So at the end of the boil you'll have around 15-16 gallons. Count on losing 1/2 to 1 gallon to kettle trub and such, or less, depending how frugal you are, and you've got a perfect 14-15 gallons.


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Dec 14, 2010
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Living free in the 603
Spike CF15 is good for 5-15.5 gallon (or 5 gallon to 1/2 bbl) batch sizes. With a total internal space of 18 gallons. That gives you enough head space for the max listed size.

I have a pair of CF10's which are 5-10 gallon batch sized. They are marked to 13 gallons in the main body, just before the lid goes on. I probably won't try to put more than 12 gallons (total) into one of them. Even that might be pushing things a bit higher than recommended.

They also have a document that shows how low the racking can will reach. On the CF10's, the lowest level is .6 gallons from the bottom of the cone. I might try extracting from the bottom (2" TC) valve on the first batch fermenting. More likely, I'll leave it so that I can see what's left in the fermenter at the end of extracting all the finished beer. Since I'll be carbonating in fermenter, filling a 3 gallon keg, and canning the rest, I'm OK with this batch (a best bitter). It will help me to figure things out when it's time to keg/can the other batch (a breakfast stout) that I brewed last weekend.