e-BIAB how big should I go?

I'm ready to buy a kettle for my e-BIAB build and I'm looking for some advice on how big a kettle to get. Right now I'm doing 6-6.5 gal batches with a gas fired 10 gal kettle. I currently get 70%-80% efficiency. I usually do a 2-gallon rinse/sparge, mostly for the added efficiency, but also because the 10-gal kettle would be pretty full with all the grain and all the water. So, I'm thinking I should get at least a 15 gallon kettle. Does anyone think I should go with a 20 gallon kettle for high gravity beers or double batches? Or is it just not possible to have big grain bills with BIAB? My one barleywine with my current setup was an ordeal and yielded a measly 56% efficiency. I'm worried that even with a bigger pot, I'll run into the same problems when trying to do a big grain bill. Bottom line: is it worth it to get a 20 gallon kettle?

Yes! I use an 11 Gallon pot for 5.25G batches and it tops out pretty quick I wish I had gone bigger for both reasons you specify. I would think your efficiency with bigger grain bills would go up with a bigger pot, because you can stir the grains and make sure that liquid is getting to the entire mash.

25 gal kettle allows me to do whatever I want. Just did a 10 gal batch of 8.5% Pliney clone. Bigger is better Zero efficiency issues even on super high gravity brews, like 1.125+

agree that size does/can matter. i have a 3 vessel 15G system and am very happy. long term you can still use as a BK and just add a HLT / MLT

I currently use a 15 gal kettle, gas fired, but when I upgrade to electric (probably after my kids are out of college), I will go to 20 or 25 gallons. In my view, the limiting factors are the ability of the bag to hold the grain without failing, and your ability to lift the bag. Since the bags are quite strong, it's really about beiing able to safely lift it, and using some type of mechanical advantage can really help.

Here's a 6 gallon Russian Imperial Stout (12% ABV), 26 lbs. of grain and 12 gal of water in the 15 gal pot. Note the slight slant of the driveway, belied by the grain stuck to the lid, that almost foiled my calculations.

I've done 40lbs + lifting out manually but that was definitely my strength limit. 40 isn't a lot by itself, until you add the absorption and remember its probably 150*.

If (when) I do that again, ill rig up some pulley system.

KIAKillerXJ said:

25 gal kettle allows me to do whatever I want. Just did a 10 gal batch of 8.5% Pliney clone. Bigger is better Zero efficiency issues even on super high gravity brews, like 1.125+


I've done 40lbs + lifting out manually but that was definitely my strength limit.

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What kind of efficiency are you getting under these conditions, particularly the big beers? Thanks.

I tend to be relatively skilled in lifting heavy things up and putting them down , but on the brew pictured above I was a bit anxious about the bag failing (probably unfounded). So I just drained most of the wort into six gallon buckets and then picked up the bag.

Regarding efficiency, I crush fine and usually get 80% or so. I didn't measure efficiency on this one. We were simultaneously brewing about 60 gallons to eventually go into a barrel, and the pace was frantic (I did back to back batches), so we sacrificed some measurements to finish the process faster. The final product was outstanding.

jeffmeh said:

I tend to be relatively skilled in lifting heavy things up and putting them down

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Says the guy with the Popeye style forearms

Regardless of ones ability to lift the bag, a locking pulley is a nice aid to let the bag drain over the kettle for several minutes.
Cheers!

sfrisby said:

What kind of efficiency are you getting under these conditions, particularly the big beers? Thanks.

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Even on those massive beers I'm pulling in 70 or more. Good crush, and correct water levels to keep a fairly thin mash as a typical BIAB is, I think makes the difference. And a large enough kettle allows that. I've never really been tempted to switch to 3 vessel or the like, because I've brewed everything imaginable OG wise with BIAB.

KIAKillerXJ said:

Even on those massive beers I'm pulling in 70 or more. Good crush, and correct water levels to keep a fairly thin mash as a typical BIAB is, I think makes the difference. And a large enough kettle allows that. I've never really been tempted to switch to 3 vessel or the like, because I've brewed everything imaginable OG wise with BIAB.

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Agreed, on all counts.

wilserbrewer said:

Says the guy with the Popeye style forearms

Regardless of ones ability to lift the bag, a locking pulley is a nice aid to let the bag drain over the kettle for several minutes.
Cheers!

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Absolutely. I tend to brew outside, or just inside my garage with the garage door overhead, so I have nowhere I could mount it. When I go electric and move indoors, I plan on getting the pulley.

I'll probably have to drive a heavy duty lag eye bolt through the exhaust hood into a ceiling joist, and mount to that. Anyone done anything similar, with both an overhead pulley and an exhaust hood?