BIAB weight limits.....

[fendersrule]

I just finished brewing a HUGE 6 Gallon beer w/ 25.6 LBs of grain. This is their standard bag fitted for a 20 gallon kettle.

My brew assistant and myself started talking about the weight limit of the BIAB...what if we wanted to double batch (10G) this huge ass beer, which would probably be about 40-42 lbs of grain.

Do you guys have any information or data?

Our personal take is that the bag appears that it could probably do 30 - 33 LBS no problem.

We are both questioning whether or not it could support 40LBs....

 

[mongoose33]

Given the straps that extend to the bottom, I'd guess it would. I'd be more concerned about the pulley and structure above.

You can also raise the bag incrementally to allow wort to drain gradually and reduce weight pressure that way.

Does your pulley have a ratchet?

 

[fendersrule]

It sure does. Its going right into the joist. It’s the nicer BIAB pulley that supports 250lbs.

 

[RM-MN]

Different but related question. What kind of brewhouse efficiency do you normally get? With a finer crush you may be able to increase the mash efficiency and then reduce the amount of grains for the same beer.

 

[fendersrule]

My Brewhouse efficiency is clockwork on 69-71%. 69% in worse case (150F mash, huge beer) and 71% best case (mid 150s mash, 6.5%erish). I usually base my recipes on 70% and tend to always come in right on.

With my slightly finer mill setting (adjusted from .027" to .025" this last go around), I wouldn't be surprised if my numbers gained a couple percentages on my best case with a more "normal" beer. I'll have a full reading when I make a more "normal" beer next time...I can't really base any improvements on the latest beer which is a 10.9%er. I was very surprised and happy to however hit 69% with it...I was expecting worse.

My next reading will be:

Mid 150s mash, 6.5% expected ABV, 60 minute mash, no mash out, .025" mill setting. Hypothesis: 71-73%

My reading after that will be:

Mid 150s mash, 6.5% expected ABV, 90 minute mash, no mash out, .025" mill setting. Hypothesis: 72-75%

If I care to look further, I will try this:

Mid 150s mash, 6.5% expected ABV, 90 minute mash, mash out, .025" mill setting. Hypothesis: 72-78%

Lots of people are getting 80% efficiency with BIAB. There's nothing wrong at all with 70% efficiency if it's consistent like clockwork. I have some hypothesis on how people are getting 80%...they either A) have a recirculating pump, B) have crushed the grain so much that it's completely powder, or C) use a mash-out + long mash +/or sparge technique.

Adding 1 hour+ to a brew day by going from 70% to 80% isn't worth it. But if it's something simple, quick, and easily to be consistent with...it's worth thinking about. Sparging is anti-BIAB and defeats its purpose (and makes water calculations/treatments a PIA) so I won't ever sparge.

 

[wilserbrewer]

Weight limits? With a proper bag and hoist I doubt you’ll come close to the limit.

Thread below I conducted weight testing to 120 lbs.

https://www.homebrewtalk.com/forum/threads/biab-polyester-voile-strength-test.384445/

And since you asked, here is a thread detailing 145 gallon BIAB, 285 lb grain bill yielding a 3 B batch


https://www.homebrewtalk.com/forum/threads/145-gallon-biab-yes-145-gallon.483965/

 

[Jag75]

Whoa man it looks like a wrecking ball lol.

 

[odie]

Those bag materials can hold a lot of weight. It's really a matter of construction...stitching and such. Wilser has done some huge bags...way beyond homebrewing scale..

 

[Kenmoron]

Just for reference, I do 3 gal BIAB batches in a 5 gal kettle. I'm usually coming in at 73-78% efficiency, no sparge. My first big beer was done recently with 13 lbs of grain and I got 70% efficiency, but this included a sparge as the whole volume wouldn't fit my kettle. One more area to look at with efficiency is mash pH, which doesn't really add time to brew day, just a meter.

 

[Cyclman]

Developed this to squeeze large grain bills.View attachment 655297

 

[fendersrule]

That’s a cool idea. Squeezing sucks.

 

[The_Goldfish]

+1 on the squeezing technique