How big of a boil kettle?

[rklinck]

So I am in the process of upgrading all of my equipment to be able to brew 10 gallon batches. I am seeing conflicting things about how big of a boil kettle I need. I know that many people happily brew 10 gallon batches using converted kegs, and I see lots of listings for 16 gallon kettles. On the other side of issue, Blichmann Engineering recommends that your boil kettle be twice as large as your intended final volume to account for boil off and room to avoid boil overs.

I'm trying to figure out who to believe because I have a lead on a 17 gallon stainless steel pot (brand new) on Craigslist that would be much cheaper than buying a 20 gallon pot. I would like advice from the 10 gallon brewers out there about whether this is big enough to not have to worry about boilovers. One of the biggest pains of my brew day is that I have to constantly monitor the boil and adjust the propane pressure to avoid boil overs until I am comfortably through the hot break (usually about 30 minutes). It would be much easier to sell SWMBO on me brewing if doing so did not require me to sit by the BK for the first 30 minutes of the boil to regulate the gas to get through the hot break.

 

[BMan1029]

17g should work just fine. I currently use a 15g kettle and do plenty of 10g batches, of a wide variety of beers. Just purchase some fermcap to help with boil overs.

 

[LovesIPA]

I think double is a fine recommendation for 5 gallon batches because you are frequently boiling off 2 gallons or so, which puts you pretty close to the top of an 8 gallon kettle.

But if you're doing 10 gallon batches, then you're still boiling off 2 gallons or so. Your boil-off rate doesn't double with your batch size. I can't imagine you would need a 20 gallon kettle.

So in short I think a 17 gallon kettle would work fine. Disclaimer: I've only ever brewed 5 gallon batches.

 

[cervid]

I'm in the same boat going up to 10 gallon size. The only thing I've found people say the 15-17 gallon pots can be borderline is with brews with a big grain bill, like barleywine.

Which I don't really ever do since I don't like it much. I've still been waiting for the right deal though.

 

[feinbera]

What LovesIPA said -- unless you get really close to the bottom of the kettle, boil-off rate scales with the surface area of where the boiling wort meets the air, not the total volume of wort. You'll probably boil off a little faster than in your 10-gallon pot, but not twice as fast. 10 gallons final volume, plus a gallon of trub and two gallons of boil-off still leaves you four gallons of "headspace" to keep boil-overs in check, which should be more than plenty.

 

[Hammy71]

I almost do 11 gallon batches exclusively. My pot is around 21 gallons in size. Occasionally I do get boil overs (well almost boil overs, I stand by with spray bottle in hand the first 5 minutes or so to combat the hot break). A 17 gallon pot should be fine though. But just be pre-warned, you will have to watch it the first couple of minutes of the boil, just to make sure. I don't/won't use fermcap in my beers. Personal choice. But really, I don't think it's a good idea to leave your brew for 30 minutes or so. Sticky wort all over your floor/driveway/deck sucks. No need to regulate the burners though, just have a spray bottle with tap water in it. Works great to 'calm the beast'.