Dumb question, but humor me

[SoCal-Doug]

Since I've built up my third rig and have some batches through it, I've been pondering on something...

I use a typical 3 vessel (converted sanke) HERMS system (HLT, MLT, BK), "hard plumbed" with valves. The MLT has a simple pickup tube and domed false bottom. The thermometer and RTD are on the wort output line so there is nothing else inside the kettle other than the return line (from the HERMS coil) at the top of the kettle. Simply a silicone tube that whirlpools during recirculation and sparging. Very much like the old Sabco systems. I am totally happy with it, and get efficiencies in the 90's, but...

What if... and don't laugh... I put a big BIAB bag in the MLT. Loosely, where the grain still fills wall to wall at mash in and still forms a nice natural filter bed. In theory, nothing has changed except there is a bag between the grain and any metal. Mash in as usual. Recirculate as usual. Sparge as usual.

Why? One single reason. At cleanup time, grab the bag, take everything out in one shot, dump it in my horse's feed bins (spent grain is like crack to horses). No scooping, no disassembling them dumping, no last 20 grains to pick out of the MLT. It's all about me wanting to be lazy at cleanup.

Thoughts? Would the bag inhibit/reduce flow? Other issues i'm not thinking of? Is there one type or another of bag that would work better? Is this more common than I thought and i'm the last person on earth to consider it?

 

[schatzke]

I use a wilser bag instead of a false bottom in my cooler for just that reason, the lazy factor.

 

[RM-MN]

Some people that have been doing what you suggest with the bag in the MLT have reported that the fine material will clog the bag and cause the MLT to overflow unless you mill the grains more coarsely than they usually do.

 

[SoCal-Doug]

Some people that have been doing what you suggest with the bag in the MLT have reported that the fine material will clog the bag and cause the MLT to overflow unless you mill the grains more coarsely than they usually do.

Hmmm. that's unbueno. Is there such thing as a coarser mesh bag? I'm pretty clueless on this bag stuff.

 

[BeardedBrews]

Some people that have been doing what you suggest with the bag in the MLT have reported that the fine material will clog the bag and cause the MLT to overflow unless you mill the grains more coarsely than they usually do.

+1 on this - my bag will stick easily with a fine crush, or with grains notorious for sticking. The holes in the bag material are much much smaller than a false bottom.

Hmmm. that's unbueno. Is there such thing as a coarser mesh bag? I'm pretty clueless on this bag stuff.

For sure!

You could try window screen material, cheesecloth, paint strainer, or you could go to Michaels where they have an open mesh net that looks almost like the hole size on a false bottom.

No matter what you pick it will have slow your re-circulation rate down a little bit, but probably not too much.

 

[shelly_belly]

I tried a paint strainer bag in my 5 gal round cooler with a false bottom, normal crush and couldn't get the wort to flow out except for a small trickle.

 

[SoCal-Doug]

Well this isn't starting off quite like I had hoped

I was really hoping for something like "you dumba$$, we've been doing this for years, where have you been?"

 

[BigJoeBrew]

I might be wrong, but I think most of us BIABers that use an assortment of bags, (I use a wilser's) aren't recirculating, and that is probably the area that it might not work for your setup. That would be a nice work/time savings though if you could get it to work.

 

[seatazzz]

I use a bag in my 16 gallon mashtun (with a false bottom & bazooka) with the standard crush from my LHBS, AND I recirculate. As long as I throttle the flow down to about a 1/4 I don't get stuck. If I let the pump go full throttle I invariably get a stuck mash. I've been getting efficiency in the mid to high 70's with this method. May also have something to do with the sparge arm attached to the lid, simple PVC tube with six holes drilled in it. YMMV. It DOES make cleanup a breeze (especially since I use the same bag in the boil kettle for hops, after dumping out the grain and giving it a good rinse). My bag is a 24 x 28 with a drawstring, don't know what the mesh measurement is but it works.

 

[SanPancho]

we use a voile (wilser type) bag inside our MLT at the nano. if you recirc, you have to throttle the flow down quite a bit. it makes cleanup a breeze, but we have problems if we mill any smaller than about .042 or so.

oddly enough, milling a bit coarser got us better efficiency. as long as you give the grains enough time to thoroughly soak and hydrate, we get decent mash conversion but much better numbers on our sparge- both in time and sugars released. kind of paradoxical i guess.

 

[wilserbrewer]

I believe Yooper does exactly what you are proposing using a BIAB bag in the MLT.

I believe her motivation was to keep particulates that sneak around the FB out of the pump.

 

[applescrap]

What you are proposing makes great sense and clearly being able to clean in place is way better than taking everything apart etc. I researched recirculation throughly (and decided it wasnt for me) and as others have stated you have to find the right balance with pump throttle or problems can happen. That being said many many people recirculate through a bag and it surely can be done. I think your idea is great and will save you a lot of time and hassle. You should go for it. Worse case is you are out 10 dollars on a cheap bag. Another advantage is if you batch sparge, squeezing the sack could get you better efficiency. And of course you get to make squeezing your sack jokes.

 

[SoCal-Doug]

I'm definitely going to do some research into materials/screening, then when I feel confident and find something that might be viable, i'll try it. I'm hoping to not go backwards on efficiency. I average 90 and 94 and have adjusted recipes over the years for that. I recirculate continuously and fly sparge via a 1.5" whirlpool over the grain bed. I've never done a BIAB thing, but that whole concept sure made me jealous when it comes to cleaning the MLT

 

[acidrain]

I've done it, and it worked OK, except the dough-in... the bag does not stay against the walls. When you stir the grains in, the paddles grabs the bag.
I tried to make a SS wire frame to hold it in-place, but that didn't work.
I thought about making a big SS wire mesh basket, but decided to just go back to a painful cleanup process (Sanke MLT).
I might make make a tippy dump next time.

 

[ericbw]

I have done it that way, with the bag on top of a tube/screen. Sometimes it makes it so the liquid won't flow through the screen, so I have to lift it up a little to keep it off the tube. That's tiring to hold it like that. Much more tiring than just cleaning out the MLT when I'm done.

For a while, though, I used a bag in the MLT with a valve, but no screen, so the bag was the filter. That worked well.