Should I use some sort of manifold?

[bigdawg86]

I have done about 12 extract kits, including a 1.135OG RIS which is **prayerfully** bottle conditioning as we speak. I did my first BIAB a few weeks ago with a 9lb grain bill. That was super easy using the standard 1 vessel setup. I decided I wanted to to the same 1.135 RIS again (Bourbon County Clone), but this time all grain.

I initially was going to go with BIAB, but realized I was pushing / over the limits with a 12 gallon kettle. I remembered I had a 60qt ice chest unused in my garage and found I already had the parts needed to convert it to a mash tun to handle the 27lbs of grain. My plan is to do a 2 vessel brew (I will likely have to temporarily put runnings in plastic bucket since my kettle is serving as HLT) . I initially planned on the DIY "bazooka" screen, but decided to invest in a rectangular brew bag (so I can winch / drip dry the bag to increase efficiency if needed).

So my question is this, should I run some sort of manifold under the grain bag? Obviously with the bag, the manifolds purpose is not to filter the grain bed, but rather to get an "even draw" from the grain bed. It seems that if I were to run just a dip tube drawing from one side of the tun that would cause uneven wort extraction. What is the consensus on this? Am I over thinking it?

 

[jalc6927]

Sometimes the bag can blog the valve, I used a false bottom in my cooler when I used a bag to mash

It worked great

I now do biab

 

[bigdawg86]

OK, so this is what I decided to do (an already built). Although I am using a grain bag, I still wanted a false bottom. So I essentially built a PVC manifold, but its going to be glued together (yellow cement) and used soley for a spacer. I then got a cheap 12x24" piece of metal mesh and cut it to size. My pickup is just a 1/2 elbow (threaded male to slip female) that I used a small piece of PVC on the slip fit side to get the pickup approx 1/8" from the bottom of a cooler. If I did this right, I get the best of both worlds. Good filtration because of the bag. Still have the ability to fly sparge (or recirculate eventually) and never get a stuck sparge... and because the pickup is so close to the cooler floor I should not have much wasted wort. Whatcha think?

 

[ancientmariner52]

Clever! That should work. Is that expanded metal aluminum or stainless steel?

 

[bigdawg86]

Clever! That should work. Is that expanded metal aluminum or stainless steel?

Well, the package didn't state what the material was. Home Depot website just lists it just as steel... contemplating finding a oven epoxy or something to paint it.

https://www.homedepot.com/p/Everbil...n-Plain-Expanded-Metal-Sheet-801417/204225783

 

[ancientmariner52]

Gotcha. I know plain steel is bad news on the hot side, but I don't know what happens at mash temps. Anybody know?

 

[tgodsill]

OK, so this is what I decided to do (an already built). Although I am using a grain bag, I still wanted a false bottom. So I essentially built a PVC manifold, but its going to be glued together (yellow cement) and used soley for a spacer. I then got a cheap 12x24" piece of metal mesh and cut it to size. My pickup is just a 1/2 elbow (threaded male to slip female) that I used a small piece of PVC on the slip fit side to get the pickup approx 1/8" from the bottom of a cooler. If I did this right, I get the best of both worlds. Good filtration because of the bag. Still have the ability to fly sparge (or recirculate eventually) and never get a stuck sparge... and because the pickup is so close to the cooler floor I should not have much wasted wort. Whatcha think?

I would use CPVC due to the temps in mashing, and also I would not use any cement. The pipes will stay together without the cement. I'm super paranoid so I would think bad stuff would leach out of the PVC or cement into the mash. Also, get stainless mesh for the false bottom if you can. If it's not SS you may get rust or weird off flavors.

 

[bigdawg86]

I would use CPVC due to the temps in mashing, and also I would not use any cement. The pipes will stay together without the cement. I'm super paranoid so I would think bad stuff would leach out of the PVC or cement into the mash. Also, get stainless mesh for the false bottom if you can. If it's not SS you may get rust or weird off flavors.

My thought on the PVC is that it is indeed drinking water safe. It is pressure rated to 140 degrees. Since I am simply using them as a spacer, I seriously doubt they will have a negative contribution at mash temperatures. Also the yellow CPVC cement is also deemed drinking water safe and is pressure rated to 200 degrees, again moot since these pipes are simply spacers. I'm not bent on using cement, but the reason I was thinking of cementing is that if sealed off then I can just clean the unit as a whole without disassembly.

I agree I need to find a solution for the mild steel expanded sheet... There are multiple high temperature products out there that are also drinking water safe.

 

[Smellyglove]

Drinking water is not hot liquor at a lower pH.

 

[tgodsill]

My thought on the PVC is that it is indeed drinking water safe. It is pressure rated to 140 degrees. Since I am simply using them as a spacer, I seriously doubt they will have a negative contribution at mash temperatures. Also the yellow CPVC cement is also deemed drinking water safe and is pressure rated to 200 degrees, again moot since these pipes are simply spacers. I'm not bent on using cement, but the reason I was thinking of cementing is that if sealed off then I can just clean the unit as a whole without disassembly.

I agree I need to find a solution for the mild steel expanded sheet... There are multiple high temperature products out there that are also drinking water safe.

Regardless of what I said I think your build is pretty awesome. I don't think I've seen someone do this with a square cooler before. Prost!

 

[ancientmariner52]

I was looking into the differences between PVC and CPVC. From what I read, PVC is more acid resistant than CPVC. The issue is that PVC is not sufficiently pressure resistant above 140°F. Recently I had occasion to bend a piece of PVC. I've always used a heat gun in the past, but I tried using boiling water this time. I found the pipe was just barely becoming flexible at boiling temp. I would have no fear using it at mash temps, unless someone can point out a proven chemical hazard. Not trying to start an argument, just want to be sure about this.

 

[wilserbrewer]

Yea I recall reading the same thing a while back, that cpvc is heat stable and structurally sound at high temps and this has morphed to PVC is toxic at high temps yet both are similar, just not structurally. Yet given this, I believe you’ll be hard pressed to find supporting info that tells you pvc is food safe at strike temps, idk as I actually researched this a bit a while back.

Regarding the OP and manifold, I doubt you need one, it would be very simple to just pull the bag clear of the cooler drain, or just perhaps use a slotted spoon in front of the bulkhead when draining.

Is that expanded sheet galvanized? Thinking it will rust, and is less than ideal for several reasons, epoxy coating seems extreme? Food grade paint idk?

Jmo, and please don’t take this the wrong way....

I feel your trying way to hard, building a manifold, false bottom AND a bag, essentially 3 systems when only one good one is required.

Be aware that unless recirculating with temp control, the space under the false bottom could actually cause efficiency to suffer, and adding temp control and recirculating defeats the advantages of using a cooler. Seems to me your building gadgets for the enjoyment of building gadgets, sorry jmo. I would have used just the bag and perhaps a piece of tubing shoved thru the original cooler bulkhead, and just tilted the cooler for a full drain, very simple and effective. JMO again, I don’t think you want that plain steel mesh in your brewery, and the pvc may be suspect as well....

The idea that you may have the ability to also fly sparge doesn’t hold much value imo, the shallow grain bed just doesn’t give me any desire to try fly sparging in a cooler BIAB system, just seems like a pain in the ass for marginal upside when high efficiency should be very easily obtained doing a simple batch sparge or better yet a super simple full volume mash as you likely have ample volume in your cooler.

Sorry if this came off negatively, just trying to help. Sometimes less is more.

And for my last piece of outspokenness, IMO you could have saved $15 on your bag for one with a drawstring to functionally hold it in place on the cooler vs some other sort of Rube Goldberging to fix the bag to the cooler.

Sorry jmo

 

[bigdawg86]

Seems to me your building gadgets for the enjoyment of building gadgets.

To be honest, I tend to do this. I am a guy who loves to tinker and build things just because I can. Although I mentioned fly sparge and recirculating, It was more for conversation. This cooler is old and I honestly don't know where it came from. I had the extra valve parts and PVC to make the tun in my garage already. The only thing I purchased was the screen. So yeah it was a fun project conceived out of boredom to some extent, so all of your observations are quite valid.

I am not planning on using this mash tun unless doing a high gravity brew, or the occasional 10 gallon batch. Like you mentioned there is no point in mashing #10 of grain in a 60 quart cooler... my SS Brewtech 12g kettle will handle most 5 gallon BIAB grain bills just fine. With that being said, this upcoming brew has #27 lbs of grain and a target OG of 1.135. I felt I'd be better served in terms of efficiency to use a mash tun. We'll see how it goes.

 

[wilserbrewer]

Ok last concern would be that your bag gets snagged on the cut edge of the mesh, not a day breaker. Sorry I’m coming off as such a negative Nancy pants [emoji158]

 

[bigdawg86]

Ok... so I did make a mistake of not using stainless mesh. Sure I can make it work, but found the cost of making it "okay" isn't much less than just buying a stainless version online. I also decided to buy a stainless screen, and I will use the mild steel one as a template.

 

[SFC Rudy]

OK, so this is what I decided to do (an already built). Although I am using a grain bag, I still wanted a false bottom. So I essentially built a PVC manifold, but its going to be glued together (yellow cement) and used soley for a spacer. I then got a cheap 12x24" piece of metal mesh and cut it to size. My pickup is just a 1/2 elbow (threaded male to slip female) that I used a small piece of PVC on the slip fit side to get the pickup approx 1/8" from the bottom of a cooler. If I did this right, I get the best of both worlds. Good filtration because of the bag. Still have the ability to fly sparge (or recirculate eventually) and never get a stuck sparge... and because the pickup is so close to the cooler floor I should not have much wasted wort. Whatcha think?

I have something like that I bought years ago. Except I use the PVC pipes as the manifold. There are rows of holes drilled on the bottom and the PVC is attached to my drain valve. The bag goes in on top of the manifold. If you wan I'll take some pics and show what I have.