Rims tube vs element under the false bottom?

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RadicalEd

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I've basically only seen RIMS systems with the heating element in the tube, or direct gas fired. Why not have the element under the false bottom? That would seem to cut down considerably on hardware costs, and allow a greater similarity between your typical 3 vessels. Is it a dead space in the mash tun issue?
 
I imagine it is to reduce the risk of scorched wort in the mash tun but I am all ears on this. Curiosity captivates.
 
I think he means that the wort would be recirculated from under the false bottom while being heated by heating element. No scorching should happen there, or at least not more than with any other RIMS approach.

I'm doing similar thing but with direct heating the wort underneath the false bottom (I have pretty big dead space there, about 7l / 1.8 gal) while recirculating it with a pump on top of the mash tun.

Only concern I have for now is how the "drainage flow" looks like. I have just a valve under the false bottom so it drains from the area nearby, and I'm a bit worried about wort area thats far from valve - is it drained too or stays there for a long time. This could lead to overheating.
 
When a stuck sparge happens, the grain is effectively keeping the liquor above the false bottom. I'd worry about firing the element dry (or semi dry) in that scenario.
 
I think he means that the wort would be recirculated from under the false bottom while being heated by heating element. No scorching should happen there, or at least not more than with any other RIMS approach.

Bingo! My thoughts exactly.

Only concern I have for now is how the "drainage flow" looks like. I have just a valve under the false bottom so it drains from the area nearby, and I'm a bit worried about wort area thats far from valve - is it drained too or stays there for a long time. This could lead to overheating.

Well, at this point of the mash you'd be filling with very warm water as you sparge, no? I think the element would be doing fairly little by that point, so one could turn it off at mash out :p.

When a stuck sparge happens, the grain is effectively keeping the liquor above the false bottom. I'd worry about firing the element dry (or semi dry) in that scenario.

Yes, but how is this any different than when using a RIMS tube? And due to the nature of an element, this setup would basically require a full size false bottom, so while a stuck sparge is conceivable, it's not terribly likely.
 
I think it would be way too much contact time with the wort. You have no way to gauge how much wort is in contact with the element. Sure the wort is circulating, but wort can sit against the element and never be circulated through, especially if you have channeling in your grain bed.
 
Yes, but how is this any different than when using a RIMS tube? And due to the nature of an element, this setup would basically require a full size false bottom, so while a stuck sparge is conceivable, it's not terribly likely.

I haven't used a rims tube, but I would think that if there is a stuck sparge, the tube would remain filled with liquor even though its not moving. I suppose the problem would be boiling in the tube, then. I haven't used one, so maybe I'm wrong.

Full size false bottoms don't eliminate stuck sparges. I think lauter tun geometry (Tall skinny tuns have more weight per inch) and recipe/mash schedule (rye, pumpkin, wheat) often play more of a role.

I'm not saying this is a bad idea, just trying to think of gotchas. I'd probably want to run a batch or two through the system before I start using an element in this way. It'd just kinda stink to be halfway through and fry the element.

I also think you are right in thinking that the dead space under the false bottom might be an issue for folks. It would need to taller than most people probably want.
 
I think it would be way too much contact time with the wort. You have no way to gauge how much wort is in contact with the element. Sure the wort is circulating, but wort can sit against the element and never be circulated through, especially if you have channeling in your grain bed.

But how then is that any different for folks using a direct fire gas heat source for the MLT?

I haven't used a rims tube, but I would think that if there is a stuck sparge, the tube would remain filled with liquor even though its not moving. I suppose the problem would be boiling in the tube, then. I haven't used one, so maybe I'm wrong.

There's some truth to this; the pump would maintain some pressure on the liquid in a RIMS tube and result in keeping some liquid in the tube. But either way, your pump is basically running dry at that point, so you can probably kiss that good-bye, and I'm more worried about the loss of a pump than an element :p.

And I'll partly agree with you on geometry--once you have a full size false bottom, the other factors (geometry, mash schedule, etc) certainly come center stage. But a 10" screen on a 20" MLT is just begging for trouble.

And I appreciate the critical Gotcha thinking! My job is basically to provide Gotcha thinking (I work in nuclear) so I certainly appreciate it's value :).
 
You stir the entire mash while applying heat.

Specifically, I was referring to those who have a false bottom and recirc with a pump, while still using gas as a heat source, but fair enough :p.

So, it is new-clee-err, or nuke-lee-er?
G H W Bush

Those are phonetically about the same, and correct; GW said "New-kew-lur" ;)
 
That might work. That's basically how you do eBIAB, except you're recirculating.

But I'd think you may have trouble with temperature control and scorching. The RIMS tube lets you get a better temperature reading on the wort you're heating: the wort flows over the element and directly onto the temperature probe. If you stick the element under the false bottom, I could see the wort right around the element not being circulated enough and getting too hot.

There's that commercial-built eBIAB system that does that (Braumeister? Brew Master? I forget the name...). Except it recirculates backwards - up from the bottom to avoid stuck sparges, and presumably the wort is pump directly over the element to avoid hot spots.
 
You would also have to have a good bit of room under the FB. That means a bunch of wort volume sitting under there. Doesn't sound very efficient to me.
 
You would also have to have a good bit of room under the FB. That means a bunch of wort volume sitting under there. Doesn't sound very efficient to me.

Well, truth be told, I'm having a FB made for my MLT and it's going to be sitting at 2" aaaanyways, so while that logic certainly applies from an initial design standpoint, I already am going to have the dead space there :p
 
I use a RIMS tube with electronic controller using a digital temp probe on my 20 gal system. I can shed some light from personal experience. The key thing is having a electronic controller to regulate the heat and not just by monitoring the temp and shutting off. You want a lower wattage on the heating element in the tube. This prevents it from heating up too fast as the heated wort needs to travel back to the top of the mash tun, onto the grain bed, back through the grain bed and then back out past the sensor in the tube. If the sensor is still just reading what hasn't been effected yet with the recirculation then it will throw off your temps. You only want the the heating element to be hot enough to gently bring up the temp it it drops. This require you to use a 4500 watt low density heating unit and you must have control of the power going to it, it can be analog or digital. But it works great.
 
I use a RIMS tube with electronic controller using a digital temp probe on my 20 gal system. I can shed some light from personal experience. The key thing is having a electronic controller to regulate the heat and not just by monitoring the temp and shutting off. You want a lower wattage on the heating element in the tube. This prevents it from heating up too fast as the heated wort needs to travel back to the top of the mash tun, onto the grain bed, back through the grain bed and then back out past the sensor in the tube. If the sensor is still just reading what hasn't been effected yet with the recirculation then it will throw off your temps. You only want the the heating element to be hot enough to gently bring up the temp it it drops. This require you to use a 4500 watt low density heating unit and you must have control of the power going to it, it can be analog or digital. But it works great.

I do something similar but with a 1650W, 120VAC RIMS tube/element. I center drain my MLT by gravity into a 2qt grant, from the grant I go into my pump, then into my RIMS with a PID controlled element, then back into my MLT. With the grant, the pump never "pulls" a vacuum on the grain bed so stuck sparges are a very rare occurence.
 
Aye, the intent was to use PID control on the element. So we still need to establish if an element under the false bottom really poses a risk to the wort.
 
I would never use a direct heating source inside the MLT even under a false bottom. If a RIMS tube is not for you then I would look at a heating element inside of your HLT with a SS coil recalculation of the wort. This will give you basically the same result as the RIMS tube. No matter how wonderful a false bottom you have, you will end up with grain in the space below it. In the Tube you have a pump pushing the wort past it and I always run the pump for about 5-10 minutes prior to turning on the heat to allow the grain bed to act as a filter making sure a minimal amount of grain is flowing in the loop. With the element in the kettle the contact time is much longer.
 
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