BIAB "Experiment" Gone Wrong

So I brewed a somewhat large IIPA on Sunday (well, the largest beer I've brewed so far), and my mash efficiency was in the toilet. I figured I would document my experience here in case it can help anyone in the future.

Up until now, I have been doing BIAB in my 5 gal kettle. With this size, and a 5 gal paint strainer bag from Lowes, I was able to fit 12 pounds of grain almost perfectly. My mash efficiencies were hovering around 80%. After doughing in and mixing the grains thoroughly, I would wrap the kettle in about 5 beach blankets and let it sit for 60 min. I never lost more than a degree and never stirred during the mash.

This time around the recipe called for about 15 pounds of grain. So, I was forced to mash in my 9 gal kettle due to head space issues. The 5 gal BIAB barely stretched around the rim of the kettle, but it held. I followed my old procedure (stir in grain well, wrap in blankets for 60 min) and again I held my temps. Unfortunately, my pre-boil gravity was way off. I think I got 51% efficiency. Here is what I narrowed it down to:

Although the BIAB fit around the rim of the kettle, it wasn't large enough to fill the inside of the kettle. This resulted in the bag pulling all of the grain into the center of the kettle, leaving a 1-2 inch ring of water between it and the sides of the kettle. The grain in the center of the bag did not end up having sufficient contact with the mash water to convert.

I guess it is time to either find a larger bag (I've heard BBaB have large laundry bags that work), or just convert a cooler to a mash tun. Either way, it doesn't appear as if the 5 gal paint strainer bags will work in my system for anything over 12 pounds of grain.

Just thought I would post this in case it has/might happen to anyone else.

Cheers

Sorry to that... Just a quick fyi, My BBaB doesn't sell the large laundry bags fine mesh draw string anymore....

I don't think that's the issue. I'm no BIAB expert, but my two batches were each done win two 5 gallon bags and they don reach around the rim of my keggle. I hold them suspended in the mash water with bungee cords and I have gotten 70% each time. There was plenty of free water around the bags.

There are a couple of vendors who make custom biab bags that would work to solve the problem as well. I don't have their url's off-hand.

FlyDoctor said:

I don't think that's the issue. I'm no BIAB expert, but my two batches were each done win two 5 gallon bags and they don reach around the rim of my keggle. I hold them suspended in the mash water with bungee cords and I have gotten 70% each time. There was plenty of free water around the bags.

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On the day I thought the same thing. But I can't narrow it down to anything else. Oh well, it will still be beer

I have no sewing skills at all, so I made a ghetto BIAB bag using a $6 voile sheer curtain, scissors, and several zip ties. It isn't pretty, but it perfectly lines my 10 gal brewpot and has made it through 3 batches without incident.

I used to BIAB in a turkey fryer and just gave up on recipes over 10-11lb of grain, because my efficiency plummeted after that. Now that I have a keggle, I can do full-volume, no-sparge BIAB even with 15lb of grain. I'm still dialing in the big grain bills, but I would suggest that full-volume, no-sparge BIAB is the way to go...if you can't do full-volume, then you are moving out of the realm in which BIAB works well. IMO. This doesn't mean you can't do big beers. I could still make a big beer in my turkey fryer, it would just be about a 3 gallon batch.

Was the crush adequate? I have heard that it makes a big difference in efficiency in the BIAB system. It will indeed be beer, and you can call it a session beer!

I always stir every 15 minutes or so to make sure it all gets wet, even with 14 lbs in the home depot bag. Maybe that might help? Another option would be to use 2 bags in the same bag and split the grain up?

Couple issues I can think of; First, stirring the mash has helped me with efficiency. I think this would be even more important in such a dense mash. I also have to ask the obvious, how well were the grains crushed. I never do more that ~11 pounds of grain in a paint strainer due to poor eff. and the fact that the bag hardly hold that much grain. Sucks, but ya live and learn.

On another note, where do we get good, premade bags? I may want to pick one up as I want to start doing 10 gallon batches...

I always thought if i was doing larger batches it would be easier to just make or get a mash tun. I personally dont need to brew that much,but i think it would be nice to have one. Which i may do someday.Just sounds like you didnt have suffiicient room for that much grain.

1. Make sure you have a tight crush - BIAB has an advantage over the traditional systems since your bag will prevent a stuck sparge.

2. Make sure you stir occasionally (may have to add some heat occasionally due to loss of checking the temperature)

3. make sure you have enough water, to ensure gelatinization of the starches.


>>Although the BIAB fit around the rim of the kettle, it wasn't large enough to fill the inside of the kettle. This resulted in the bag pulling all of the grain into the center of the kettle, leaving a 1-2 inch ring of water between it and the sides of the kettle. The grain in the center of the bag did not end up having sufficient contact with the mash water to convert.

BBaB has a cotton laundry bag (unfortunately for $8) that I am going to try. I hope it doesn't absorb too much wort, though I use a 2 stage method where I mash, then sparge the grains in a different pot.

If anyone can locate an inexpensive commercially available bag that is good for BIAB please let me know

[ I am sure the $35 BIAB bags some sell here are excellent, I'd just prefer to pay less if I can ]

My brew shop sells a large bag that fits my 8 gallon brew kettle with plenty of room to spare. I actually have a lot of extra bag when I use it in my kettle.

http://www.barleynvine.com/5054.html

D_Nyholm said:

On another note, where do we get good, premade bags? I may want to pick one up as I want to start doing 10 gallon batches...

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Hit up Wilserbrewer on this site. $20 for a custom bag well worth it.

Stirring the grain in a tight, compressed mash like that should have certainly helped.

If you don't want to deal with sparging and a manifold in a cooler, just get a bag large enough to line the cooler and mash in there. I know you could use your 9g. pot, so that's fine too.