RIMS vs HERMS...Your opinions please

[Big-H]

Thanks for posting your test results. What was the total volume of water in this test?

It was a quick test using 5 gallons of 55º water. Sorry, I intended to include that in the results.

 

[Big-H]

I'd calibrate both of the temperature sensors in boiling water and then check them in ice water - make sure they are reading the same. Looking at your setup, it appears that the PT100 is quite a ways away from the element. If your flow is slow, the response of the system will be slow and the possibility of wort scorching will be higher. Try and get the PT100 probe as close to the element as possible.

Thank you for the advice. I will calibrate them. There was a 1º difference between the two readings before I turned on the heat, but It would be nice to know exactly.

I tried to come up with a config that would get the sensor closer to the element, but with the fittings I had that was the best I could do. I'm sure that was part of the lag or over shooting of the temp. I'm keeping my eye out for a solution to get the sensor right at the end of the element.

I plan to brew next weekend so I'll see how the circulation does with a MT full of malt.

 

[orangehero]

Calibrating the temp probe at boiling and freezing is not particularly valuable for this application as neither of those temperatures are used during mashing. It would be the best alternative if you don't have another accurate reference thermometer, as you know the temperature at which pure water freezes and can calculate the temp pure water should boil at your location if you know your altitude and barometric pressure.

As long as you have another accurate thermometer, you should calibrate at mash temperature.

 

[Big-H]

Since I don't have a ThermaPen, i went ahead and checked the temps with ice water and boiling water. One probe was returning 1º too high at both freezing and boiling (I live at 84 feet above sea level) and the other was 3º too high at both freezing and boiling. My assumption is that the offset would be fairly consistent throughout the spectrum. I set the PID's to compensate for the different readings. On my PID's (Auber Instruments) at the Pb setting I set -1º and -3º respectively. The next thing I need to do is run an auto tuning sequence on the controlling PID (the other PID is only monitoring the outlet temp on the mash tun...information only) so that it learns the characteristics of the system. This may iron out the overheating I was experiencing earlier...we'll see.

 

[blizz81]

Yeah, the auto-tune definitely helped mine stop overshooting.

 

[Big-H]

Auto tuned today using just water circulation in preparation for brew day tomorrow. Its amazing how the PID's "learn" to not overshoot the temps.

I was concerned that the circulation rate of the wort versus just plain water would be a lot slower so I necked the flow down using a ball valve to simulate a slower flow rate. I then performed the autotune procedure.

After auto tune the RIMS temp stayed within 1º-2º of my desired temp and more importantly the outlet of the mash tun was spot on to my desired mash temp.

With the 6000 watt LWD element I can heat strike water using the RIMS tube.
I should be able to do step mashes quickly and efficiently. My simulated 3 step mash today heated 7 gallons of water from 52º to 145 in approx 15 minutes, from 145º to 155º in approx 8 minutes in a very controlled manner and then from 155º to 168º mash out in approx 10 minutes.

I then heated the entire system to 212º to sterilize the components in prep for tomorrows brew. No problems whatsoever.

Overall I'm pleased with the responsiveness of the system and the fact that it doesn't seem to run away with the temp. I think this translates into not scorching the wort as so many have warned about. The element, while maintaining a set temp, only fires for 1 or 2 seconds at a time and never gets out of control.

Tomorrow is the big test. I'll keep you posted. If I can maintain my mash temps consistently I will consider it a flaming success!

 

[Big-H]

Just finished my brew day and here's the report on the new RIM's system.

The beer I did today called for a 3 step mash, perfect for putting this through its paces. 1st step 145º for 90 minutes, 2nd step-raise to 155º and hold for 30 minutes, 3 step-raise to 168º, hold for 10 minutes, then mash out at 168º.

I added the necessary amount of strike water directly to the mash tun, turned on the RIMS element to 153º and went to grind the grain. Before I got the 16.5 lbs of grain crushed the mash tun was up to temp. Added grain, stirred, and let set for 5 minutes, turned on pump and adjusted valve to get a good whirlpool in the mash tun. After I was satisfied that the flow was going to remain constant I turned on the element to 145º. The mash had only dropped a couple degrees in the interim so it only took 4 or 5 minutes to stabilize at 145º. Now here's the cool part...The mash stayed at 145º for the entire 90 minutes! No fluctuation whatsoever!
I then bumped the RIMS element up to 155º the mash temp came up slow and steady. It probably took 10 minutes to hit 155 and then held steady for the next 30 minutes. The raise to 168 took about 15 minutes and again held steady for the rest of the mash.

In summary: I'm very very happy with the performance of this system. The temps were accurate and steady at all times. The response was fast and consistent. Never once did I have any thoughts that the element was getting too hot for the wort. The PID cycled the element for short bursts even when called on to raise the temp several degrees.

I did not have any circulation problems but if a person had a stuck mash or pump problem I could see how that may create issues. Keep the wort flowing = no scorching.

Thank you to everyone that gave their experience and wisdom to this project. I appreciate the advice and the conversation. I hope this helps someone else as they build their systems.

 

[augiedoggy]

The PID cycled the element for short bursts even when called on to raise the temp several degrees.

Not for nothing but if you raised the setpoint 10 degrees and your pid kept pulsing the element in sort bursts the whole time then I would think something was wrong?
Its not supposed to start pulsing until it reaches (or comes very close) to reaching the desired setpoint. it would be much less efficient that way... This is why having a heating element with very low watt density matters so much (for when the element is on 100% duration)...

 

[GotPushrods]

Not for nothing but if you raised the setpoint 10 degrees and your pid kept pulsing the element in sort bursts the whole time then I would think something was wrong?
Its not supposed to start pulsing until it reaches (or comes very close) to reaching the desired setpoint. it would be much less efficient that way... This is why having a heating element with very low watt density matters so much (for when the element is on 100% duration)...

This would be true when heating a large volume, but remember in a RIMs tube the temp probe is at the output of the tube, not in the mash itself. It is heating a very small volume. If it has to go from 10% to 50% when you bump the setpoint then that's all it needs. Sure you could heat a lot faster by maxing out the RIMs tube output, but then you're denaturing enzymes and possibly scorching the mash as it passes through.

 

[augiedoggy]

This would be true when heating a large volume, but remember in a RIMs tube the temp probe is at the output of the tube, not in the mash itself. It is heating a very small volume. If it has to go from 10% to 50% when you bump the setpoint then that's all it needs. Sure you could heat a lot faster by maxing out the RIMs tube output, but then you're denaturing enzymes and possibly scorching the mash as it passes through.

Ah the difference here is I was assuming his pid temp probe WAS the one at the exit of his rims tube because that is the way mine is set up.(I monitor MT temps at the exit as well but theres direct tie to the element..

If I go from 145 to 155 (10 degree increase) with my pumps going at about 2gpm then my rims element will stay on until the temp reaches the setpoint... with the wort constantly moving at such a pace across a >40 wPSI element there is no scorching going on.. not such about the enzymes because its still fermenting but my gravity came out much higher than expected. If I do have issues I will slow the flow down.

 

[GotPushrods]

Ah the difference here is I was assuming his pid temp probe WAS the one at the exit of his rims tube because that is the way mine is set up.(I monitor MT temps at the exit as well but theres direct tie to the element..

If I go from 145 to 155 (10 degree increase) with my pumps going at about 2gpm then my rims element will stay on until the temp reaches the setpoint... with the wort constantly moving at such a pace across a >40 wPSI element there is no scorching going on.. not such about the enzymes because its still fermenting but my gravity came out much higher than expected. If I do have issues I will slow the flow down.

Gotcha, I'm just guessing here as I'm all HERMS. I suppose it will depend on wattage and flow rate. With a high enough wattage and/or slow enough flow rate I'd think it would be possible to safely raise the output 10 degrees without maxing out the PID pulses, but I have never done this. I am far from an authority on RIMS. If most people only get a few degrees per pass from their RIMS, then I guess it would be strange that it was still pulsing. Could also indicate slower than expected flow due to mash starting to stick? I have a vacuum gauge for this very reason. I built it in just for fun, but it's been very useful. I keep an eye on it and throttle back if vacuum starts to rise.

 

[Big-H]

I had two probes in the system the one controlling the pid was as close to the element as I could get it with the fittings I had. The other one was monitoring the outlet of the MLT. (informational only)

When I said that the pid was pulsing I guess I might have used the wrong word. What I meant was the the pid would fire the element until it saw the new temp at the probe, in this case going from 145 to 155. It only would take a few seconds to raise the temp in the tube to 155 and then it was off again. It seem after a few cycles that the pid started "anticipating" the approaching cutoff temp and shut off the element ahead of the desired 155 temp, but maybe this was my imagination. I felt like this was a very controlled way to raise the temp of the MLT because it (the MLT temp) gradually came up over the course of 10 to 15 minutes. I think if you were going to do a large temp step, more than 15 degrees, it might be advisable to do in in increments to insure the element didn't stay on too long.

Overall I'm very satisfied with the performance of the system. Im not sure that I would recommend using a low wattage element because I did not see any down side to it. The upside is you can use the RIM's to heat strike water and raise temps when you would like to. I've read others say the 110V elements or the low low wattage elements are only adequate to maintain temps.

Anyway thats my 2 cents

 

[augiedoggy]

I had two probes in the system the one controlling the pid was as close to the element as I could get it with the fittings I had. The other one was monitoring the outlet of the MLT. (informational only)

When I said that the pid was pulsing I guess I might have used the wrong word. What I meant was the the pid would fire the element until it saw the new temp at the probe, in this case going from 145 to 155. It only would take a few seconds to raise the temp in the tube to 155 and then it was off again. It seem after a few cycles that the pid started "anticipating" the approaching cutoff temp and shut off the element ahead of the desired 155 temp, but maybe this was my imagination. I felt like this was a very controlled way to raise the temp of the MLT because it (the MLT temp) gradually came up over the course of 10 to 15 minutes. I think if you were going to do a large temp step, more than 15 degrees, it might be advisable to do in in increments to insure the element didn't stay on too long.

Overall I'm very satisfied with the performance of the system. Im not sure that I would recommend using a low wattage element because I did not see any down side to it. The upside is you can use the RIM's to heat strike water and raise temps when you would like to. I've read others say the 110V elements or the low low wattage elements are only adequate to maintain temps.

Anyway thats my 2 cents

see your system and performance is like my last rims tube... I found out the hard way there are downsides as I scorched three brews without realizing it until its too late...
Basically the heat at the element is very intense on higher watt density element and unless the flow across it remains very fast you can easily scorch your beer, not to mention the denatured enzyme possibility.

ulwd elements will still raise temps its just gradual like a herms coil.
This is why my new rims tube is 28" long with a 25" long 1,000w element... more contact time at less intense heat is always better here.

 

[JoshuaW]

Happy medium is running a 5500w element switchable between 240v and 120v. 1375w for maintaining temps, 5500w for heating cleaning water, sparge water, etc. Granted I dont have my system complete yet, but based on what you have said, 1375w should get me a slow rise. If for some reason I need a quick boost, switch it over to 240v.

 

[augiedoggy]

Happy medium is running a 5500w element switchable between 240v and 120v. 1375w for maintaining temps, 5500w for heating cleaning water, sparge water, etc. Granted I dont have my system complete yet, but based on what you have said, 1375w should get me a slow rise. If for some reason I need a quick boost, switch it over to 240v.

thats 1375w over a 4ft length of heating element (folded over) on a standard lwd element... Thats the key factor because it makes the watt density per square inch lower.

 

[Big-H]

see your system and performance is like my last rims tube... I found out the hard way there are downsides as I scorched three brews without realizing it until its too late...
Basically the heat at the element is very intense on higher watt density element and unless the flow across it remains very fast you can easily scorch your beer, not to mention the denatured enzyme possibility.

ulwd elements will still raise temps its just gradual like a herms coil.
This is why my new rims tube is 28" long with a 25" long 1,000w element... more contact time at less intense heat is always better here.

Point well taken. I'm installing a vacuum gauge on the outlet of my MLT to monitor the outlet negative pressure. Trying to prevent a compacted grain bed with the goal of maintaining as much flow as possible. Its hard to know if you are compacting the grain if there is no way to monitor vacuum. I read somewhere that the maximum vacuum you want to see is about 2.5 3 psi. Also, if a person can maintain the temp below denaturing temps for whichever enzyme you're trying to maximize you should be golden. Right?

 

[augiedoggy]

Point well taken. I'm installing a vacuum gauge on the outlet of my MLT to monitor the outlet negative pressure. Trying to prevent a compacted grain bed with the goal of maintaining as much flow as possible. Its hard to know if you are compacting the grain if there is no way to monitor vacuum. I read somewhere that the maximum vacuum you want to see is about 2.5 3 psi. Also, if a person can maintain the temp below denaturing temps for whichever enzyme you're trying to maximize you should be golden. Right?

Not sure about vacuum ( but what you say makes sense) I installed this rotometer and used it for the first time last nght...I learned that according to it my mash recirculation is consistently about 1.5-1.6 gallons per minute with the 4 feet of headspace and grain bed slowing down my small 24v pump...
I get just over 2gpm of sparge water flow max when turned up all the way... these pics are from the beginning of the mash so color is off and the wort was very cloudy but it was clear at the end of the mash and much easier to read from a distance...and my speed flow never dropped which is good.
This meter was $22 shipped from ebay BTW... http://www.ebay.com/itm/33135307974...49&var=540545512831&ssPageName=STRK:MEBIDX:IT I got the idea from someone else on this forum.

btw yes you can do step mashes to produce different protein chains and break down complex sugars with a rims... my system is slower than most due to the uninsulated mash tun and lower flow pumps I can increase temps about 2 degrees per minute in some cases but it depends on the size of the mash as far as actual step mashing speed...

 

[USAFSooner]

I went RIMS. If I had to do it again I would go HERMS for a couple reasons:

* wort never comes in contact with the heater element
* element only comes in contact with water and will not get burnt on carbon crud from the wort
* zero chance of scorching the wort
* cleaning the SS coil is far easier than periodic disassembly of a RIMS tube

 

[bd2xu]

Love my herms. It makes for a heavy HLT but for all the reasons you said plus I can heat about two degrees per minute when needed, again with no chance of scorching. I built my HERMS after scorching the hell out of a 10 gallon partigyle lager batch while doing a direct fired mash tun.

 

[augiedoggy]

I don't really see how the inside of a 50' coil is easier to clean than popping open a trip clamp or cam lock in my case and cleaning off the element...

 

[MrNatural]

I don't really see how the inside of a 50' coil is easier to clean than popping open a trip clamp or cam lock in my case and cleaning off the element...

How about not popping anything open and not cleaning off anything?

https://www.homebrewtalk.com/f11/question-about-herms-pump-lines-510336/#post6630704

 

[BillKlineVT]

Ditto... I just run my sparge water through the coil and then it's good to go

 

[augiedoggy]

How about not popping anything open and not cleaning off anything?

https://www.homebrewtalk.com/f11/question-about-herms-pump-lines-510336/#post6630704

That's what I did with my herms then when I tried cleaning the 4ft or so with a beer line brush Just to see how clean it was I had found I had some nasty stuff hiding in there... had a slimy coat come out in flakes.
I'm guessing g at one point I didn't flush it out well but its not ideal not knowing what's lurking in there especially when the toxic green stuff could be growing on the copper... stainless would prevent that though.... its kind of like using a plate chiller I guess which I do so I don't know...