I have seen several people post pics of using a bag in the mash tun of a two or three vessel system. I can see a big advantage during clean up. Any problems using a bag with a recirculating system (RIMS or HERMS)? Perhaps Wilserbrewer can chime in...
Using a bag in your MT
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bstacy1974
Well-Known Member
RIMS system for me. No issues at all. I've tried both single and double crush with no real gains, so I've stayed with single crush. No rice hulls. Never had pump issues or stuck sparges. I almost always batch sparge, but have tried a fly sparge in the past without incident.
I use a cheap (29" x 29") bag from Amazon. It's huge and has no issue fitting inside a 10 gallon igloo cooler.
I use a cheap (29" x 29") bag from Amazon. It's huge and has no issue fitting inside a 10 gallon igloo cooler.
Gnomebrewer
Well-Known Member
It works well but you can't use the fine crush that BIAB brewers use - you won't get filtration through the grain bed. Basically the bag is just replacing the false bottom (or other manifold).
Could one simply sit the bag on top of an existing false bottom?
cyberbackpacker
Well-Known Member
Yes!
Great question to ask Steve, and very pertinent to me as well.
@Gnomebrewer good point on the grain bed filtration. I'm planning to do this as well and I wouldn't have thought of that. Do you think a fine crush with conditioned grain would give you the best of both worlds? High efficiency + whole husks for filtering? Or could you just add some rice hulls?
@Gnomebrewer good point on the grain bed filtration. I'm planning to do this as well and I wouldn't have thought of that. Do you think a fine crush with conditioned grain would give you the best of both worlds? High efficiency + whole husks for filtering? Or could you just add some rice hulls?
I don't know from first hand experience in a 3 vessel system, but I have used a false bottom with a bag in my current biab system for step mashing and had no issues other than the bag getting pulled down around the edges of my makeshift false bottom. With one that fits properly I doubt this would be an issue.
In the 3 vessel system I think the false bottom would just add to the chore of cleaning, since you would have to remove it to clean the dead space underneath. With only a bag, you could flush with water and clean in place without disassembly (I think)
Gnomebrewer
Well-Known Member
With conditioned grains, you're still limited to about 0.025" to get flow through the grain bed (and that's being careful). Many BIABers go much finer than that. Adding rice hulls would probably help (I haven't tried it) but is adding cost.
The high efficiency from BIAB mostly comes from squeezing the bag though. As long as the crush is fine enough to allow complete extraction of starch, you can get 100% conversion, but it takes a bit longer if the crush is coarser. I get full conversion in about 75 minutes with a crush at about 0.03" (dependent on mash temperature). Milled to flour, I've heard it stated that it happens in a few minutes. Either way, as long as you mash until you have full conversion, super high efficiency will come from the bag squeeze - would you want to do that after a recirculated mash?
Nevermind I asked a stupid question...
You're referring to conversion efficiency and brewhouse efficiency which accounts for losses throughout the system, I was referring to mash efficiency: total gravity points in the mash vs potential extract in the grain, which is conversion efficiency * lauter efficiency... Mash efficiency is often higher in a 3-vessel system since they can sparge which extracts more total sugar than squeezing. I was mixing up mash and brewhouse efficiency.
So no I don't intend to squeeze a bag after recirculation, but I may end up batch sparging if I find that my mash efficiency is too low to live with. I may also just end up adding $1.50 in grain and live with a no sparge
While I have made and sold many bags for this purpose, I have never lined a MT with a bag.
Never had any negative feedback...sorry that’s all I got...
Big advantage I’m told is that you will not experience pump or plate exchanger clogging during the mash.
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