Rims system scorching

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James Law

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ok everyone, I have been doing BIAB for some time and never had a scorched wort. My current setup is a 240v 5500w rims system with a 2"x 18" rims tube with dual 3/4" outputs. This is the first time this is happening. While bringing the wort up to 149° alpha saach rest I started to notice a burnt smell, so I drained the rims and sure enough the element was covered in burnt flour if you may. The pump is flowing well and I make sure I have good flow prior to turning on the element. After cleaning the element I attempted ramp up again going no higher than 60%..... still scorching. The viscosity is good, and I'm wondering if any one is or has experienced these issues. The element is a lwd element. Im wondering if i need to find a ulwd straight element (or if they even exist cause I'm having a herd time finding them) any insight would help.... thanks
 
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James Law

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Update: seems after the time it took to clean the element 3 time I got some starch conversion and I added some more water to dilute, things seem to be going good now.
 

Vale71

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I'd look at two things first:

- flow rate, you can measure it by dumping the wort in a measuring container and timing it
- amount of solids in the wort, you can estimate the amount by letting the wort from the first test decant

If you're getting low flow and/or a lot of solid particulate then you'll have an idea of what to start working on.
 
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James Law

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I have a manual (dial) style controller. And the temp probe is mounted at the opposite end of the rims tube.



Vale:
So I had full flow on a chugger, no issues there. What I found to be the issue (I think) was the amount of dilution or water per pound of grain vs the amount of free starches getting to or caking on the element. So in the future, I will make sure that I add sufficient water to grain.
Lessons learned!
 

Bobby_M

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Another thing is mounting orientation. Think like an air bubble and figure out if air would naturally be purged out during flow. Any air bubble would be an instant mess with that kind of power. How long is the current element? Is it a foldback or just a single loop?
 
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James Law

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Its a fold back LWD. I did find a lot of research on the bubble factor as well. So after I put it all back together the 3rd time I ensured that it was absolutely free of air. Can't say I did that the first few times. The element is a 12" if im not mistaken and the tube is 14" with vertical 3/4 triclamp fittings
 

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Vale71

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Vale:
So I had full flow on a chugger, no issues there. What I found to be the issue (I think) was the amount of dilution or water per pound of grain vs the amount of free starches getting to or caking on the element. So in the future, I will make sure that I add sufficient water to grain.
Lessons learned!
If by full flow you mean nominal flow rate that's impossible as you'll have so much resistance mostly from the grain bed and false bottom that what you'd get is only a fraction of that. If actual flow is too low then a 5500W element can get very hot, even an lwd one, and that can cause scorching.
One other important aspect is whether the starch was fully gelatinized when you started firing the element. If this wasn't the case then viscosity would have been very high, also affecting flow rate, and you'd have a lot of ungelatinized starch flowing through the tube and possibly sticking to the element and causing scorching. In that regard at what temperature did you start the ramp up?
 
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James Law

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Well i usually try to keep the grain in suspension (don't know if that's the wrong thing to do) in order to keep the brew bag and false bottom from settling in.
On this particular tripel, I did a protein rest ( i say rest, but I kept the pump and element running to maintain temp. Which in hind sight may have been another factor in my issue.) @ 122f for 30 min and was during that time that I had my first 2 scorches. And it wasn't until it had ample time to "rest" that some of the starches broke and I was able to ramp up to 149 for the alpha saach, where I was able to maintain temp without issue.
 

micraftbeer

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I have scorched on an even lower power, lower watt density RIMS (2000W Blichmann RIMS Rocket). If I got a stuck mash, it was pretty instantaneous. So it might not be as complicated as gelatinized floating starches, and could be using a high flow pump with a thick mash and you starved the pump.

Same solution would work for you, though, thinning your mash by adding more water.
 

Vale71

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Without a properly setteled grain bed you'll always have an inordinate amount of suspended solids which means you'll most likely always have scorching with such a powerful element. Unless you get clear wort to circulate the most you'll be able to do is use a very low power setting just to recirculate and maintain temperature which precludes multi-step mashes.
 
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James Law

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There may inlay some of my problems. I currently use a brew bag that sits on top of a cross slit style false bottom. This combination tends to plug up fairly easily, even with rice hulls in the grain bed. Im trying to source some ss mesh or screen now that I have been talking with you all. I think if I open up the available drainage space seeing as I am using a brew bag, I could easily get the grain bed to settle without drying the pump out... comments thoughts?
 
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James Law

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So while the brew bag is nice and all, with a slit style bottom if i use rice hulls should I have any issues removing the bag and just using the false bottom alone? Now my keg is set up where I cut the bottom out and it drains out the Sanke fitting. So this allows for a good amount of total drainage surface area. I will give it a go without the bag and see how it goes it guess.
 
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Hi there. I think the problem you have is compounded... too much power being dumped into too small of an element, which is inside too large a diameter of a RIMs tube. My suggestion is you run the element at 120V and/or set your controller for no longer than a 2 second duty (1 would be better if it has the resolution). Consider limiting the max output power to 25% if you cannot run it at 120V. Also, get a 1.5" tube. While you are at it, consider a longer one and a longer, lower density element if possible. Make sure your tube is vertically mounted.
 

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So while the brew bag is nice and all, with a slit style bottom if i use rice hulls should I have any issues removing the bag and just using the false bottom alone? Now my keg is set up where I cut the bottom out and it drains out the Sanke fitting. So this allows for a good amount of total drainage surface area. I will give it a go without the bag and see how it goes it guess.
I don't understand why you are using a bag with recirculating the wort. That is like putting a screen inline with your RIMS tube.
My suggestion is to eliminate the bag and just use the false bottom. I use a bazooka screen in my cooler mash tun with success.
 
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James Law

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Hi there. I think the problem you have is compounded... too much power being dumped into too small of an element, which is inside too large a diameter of a RIMs tube. My suggestion is you run the element at 120V and/or set your controller for no longer than a 2 second duty (1 would be better if it has the resolution). Consider limiting the max output power to 25% if you cannot run it at 120V. Also, get a 1.5" tube. While you are at it, consider a longer one and a longer, lower density element if possible. Make sure your tube is vertically mounted.
So now that I have talked to everyone, I've figured out that I have been keeping the grain in suspension and not letting the grain bed settle causing the rims system to have too much particulate in circulation. I have been using this current combination without any pid and just using a potentiometer to manually control the temperature. I think maybe in the future I will change to a PID, but for now I am going to implement some of the changes that have been offered up. But the 120V idea is a good one in the case that I continue to have issues. Thanks
 
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James Law

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I don't understand why you are using a bag with recirculating the wort. That is like putting a screen inline with your RIMS tube.
My suggestion is to eliminate the bag and just use the false bottom. I use a bazooka screen in my cooler mash tun with success.
I see what you mean. I will give her a go without the bag and see how it goes... thanks
 
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I tried BIAB recirc with a RIMS tube for a while. I had terrible problems with stuck mashes. I decided to switch to traditional 3 vessel...and ended up having a few stuck mashes! What I learned is that you need to start the recirc very slowly to "set" the drain bed within the grains. After things are flowing freely/more clear the rate can be increased a bit. I still can't open my pump valve full during a mash, but I can get enough flow to hold temps. I am using a 120v element with much less wattage.

I never did go back to BIAB to see if that learning would have solved my problems with those stuck mashes, but I am certain it would have helped.
 
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James Law

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I tried BIAB recirc with a RIMS tube for a while. I had terrible problems with stuck mashes. I decided to switch to traditional 3 vessel...and ended up having a few stuck mashes! What I learned is that you need to start the recirc very slowly to "set" the drain bed within the grains. After things are flowing freely/more clear the rate can be increased a bit. I still can't open my pump valve full during a mash, but I can get enough flow to hold temps. I am using a 120v element with much less wattage.

I never did go back to BIAB to see if that learning would have solved my problems with those stuck mashes, but I am certain it would have helped.
I think that's what I'm gonna do, just keep it simple and use the false bottom for what it was intended and incorporate all of the good information that has been provided by all of you!
 

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what was the mash grain bill? there wasnt any rye was there? I agree 5500w elements really need to be ULWD to lessen the chance of scorching with the low flow speed of a typical 5-10gallon setup.. it sounds like you might not even have a lwd element... one easy fix would be to use the pid inline after the potentiameter controller and leave the knob turned down about half way which would effectively lower the watt density of the element surface.
 
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James Law

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So just to give closure to this thread. I am now using a custom made SS screen with 1/4 openings along with a brew bag. This is allowing me to get enough wort though to keep the pump speed that I want. I still get a little bit of stuck on turb if you may on the element depending on the grain bill and temp that I run. But I have yet to scorch another mash. Thanks to all for their help.

Cheers
 
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