Methods to achieve accurate temp readings?

Still in the planning stages, but was wondering how to create a system of accurate temp readings.

Mash - planning a circulating rims or herms system RTD would be inline with the flow. It would be directly in the RIMS? Before or after the element?

HTL - I think I need to pump water from the bottom to the top to mix. Then the RTD would be a kettle mount.

Brew pot - Pump water to circulate? RTD would be in the kettle?

Chiller - T into the chiller with the oxygen stone?

 

Mash... I do mine inline just outside of mash tun. I want to know temp of the mash I am heating not of the Wort flowing through the RIMS or after.

The other two I have mounted right in the HLT and in Boil Kettel. I use an RTD with 1/2" NPT in a camlok disconnect so I can easily remove them for cleaning

 

I also monitor mash temps in my RIMS system in a similar way. I control the RIMS tube with an RTD temp sensor and PID on the output of the tube so that it doesn't overheat the wort, but I monitor the mash temp itself with a CDN instant read thermometer mounted (using Bobby_M's kit) on a tee at the outlet of the cooler mash tun.

If you need or want to control HLT temperatures, then either an internal stirrer and a thermometer mounted through the pot wall, or an external recirculating system with a thermometer on the HLT output should work well. Either should be consistent, which is slightly more important than absolute accuracy.

And now for the slightly non-conventional bit that might not be useful for you:
For the HLT I don't bother to monitor temps, and my HLT is unheated. I heat sparge water in my boil kettle (using gas stove or propane, although I'm working towards going electric when we buy a house) to about 180F, transfer to a 5 gallon cooler HLT, at which point it's just below 170F. I then fly sparge by pumping the sparge water through the RIMS tube at a slow rate to the mash tun (although I still have to pump it in batches because I can't run my pump slow enough). The RIMS tube can take care of a 20F loss in sparge water temperature from the cooler HLT, and avoids the need to control or even heat the HLT at all. The sparge water also rinses the RIMS tube.

If you are running RIMS instead of a HERMS, you don't need very tight control of the HLT temperature, even if you don't feed the sparge water via the RIMS tube. Sparge water just needs to be hot, but not too hot (and there are those that debate whether sparge water needs to be hot at all). If you are happy heating strike and sparge water in your boil kettle (with a bit of RIMS tube use to fine tune the strike water temps), you don't even need to heat your HLT at all.

Not suggesting that this is the best way for you, but it does work pretty well, and gives an easy development path. You can always switch to a heated and controlled HLT later. I guess what I'm asking/saying is: How accurate do you need/want your measurements to be?

 

I am an electrical controls engineer for a living, so I know a lot about this subject.

I use a RIMS and put the RTD immediately at the output of the RIMS tube. (I have a full P&ID of my system in the link in my signature.) You do not want to put the sensor in the mash because you'll have too large of a delay between the element (your controlling output) and the mash temp (your input). Depending upon how you get your controller tuned you'll either have sluggish perform, or overheat your mash as it passes through. By placing the RTD at the RIMS output you prevent the mash from instantaneously being overheated. Part of making this work well is throttling the pump correctly and consistently too. I hold temperatures to less than a degree of error with my set up, that goes for HLT, mash, sparge, etc, etc.

HERMS is a different technique. I haven't examined it in great detail but I believe Kal's implementation is the proper way to do it.

 

I was actually gonna post a question on the same topic. Kal's system uses a pump to cycle the HLT water, and the output temp of the HLT fires the HLT heating element. I was curious whether you'd get too much hysteresis (I think that's the right term) if you used the mash tun outlet. I only have one pump for my propane HERMS right now, and as I upgrade to electric I want to spend that money elsewhere. I'm guessing it would be wrong to use HLT temp if you don't have a means of stirring the HLT, which Kal does.

 

So I am thinking the same as other people.

RIMS = PID control on the output of the RIMS unit.
I will also add a reference temp measurement on the port of the mashtun.
I need to see how people add a temp probe to a tri-clamp system. Do they make a standard triclamp port I can buy?

HLT, will recirculate via a pump, then read direct from the HLT

Boil Pot? Same thing, recirculate or does this matter since it needs to boil. And when it boils it will recirculate?

I don't want to use the boil pot as a heat source for water.
I want to be able to run back to back batches.
(Boil wort and heat the mash water at the same time)

 

Can only speak for mine & this worked best...

PID sensors -

*** 1 at the input return back into the MLT. (typically a 2 degree differential between the MLT & HERMS/HLT temp. Everywhere else I placed it resulted in a much larger variance between the two.)

*** 1 in the brew kettle. This is mainly to monitor temps during hopstand & whirlpool hop additions. Not the boil.

Dial thermometers...

*** 1 in the MLT measuring the mash temp, 6" probe.
*** 1 in the HLT measuring HERMS heating water temp

Single PID controller.

I am also running a recirc pump on the HLT to make temp ramping more efficient & minimize stratification.

 

I was monitoring my temps for the PID control at the outset of the RIMS tube but moved it to the output of the Mash Tun since I found the temps between the mash tun and the tube were quite a bit off. I want to regulate the temp of the mash itself, not the wort coming off the RIMS. once it infuses with the mash it changes temp anyhow. I started to get much more consistent and accurate mash temps and controlled raising the mash temps better when I monitored right at the output from the MLT. This way I get the reading of the mash itself minus the little loss of heat from exiting the MLT.

Just my observation on my system, everybody's will be different.

 

There is more than 1 way to make this "work" and make beer, but there are some ways that are better than others. I disagree that you don't want to control the temperature coming out of the RIMS tube. You want to use that to control the temp of the mash itself. If you're overheating the wort coming out of the RIMS tube you could be denaturing enzymes and your results won't necessarily jive with others who use a given temperature profile. Once the controller settles and you recirculate the mash a little more than once (~10 minutes) you should be dead nuts on your set point, if your controller is tuned right.

I did have a lot of troubles initially with the tuning. I throttled the pump back to about 2 qt/min and softened the integrator gain that the auto-tune came up with. If you're holding temps steady at the output of the RIMS tube your mash tun will eventually settle very close to that temperature. I hold steady to less than a degree of error, and my RIMS RTD agrees dead on with my mash analog thermometer once it has settled.

 

You can buy Tri-clamp RTD's from Auber and ebrewsupply (I believe ebrewsupplies are designed only for BCS). Or you can get tri-clamp thermowells from brewershardware. Hope that helps.

http://www.auberins.com/index.php?main_page=product_info&cPath=20_15&products_id=267

http://www.ebrewsupply.com/bcs/temp-sensors/tpbcstc157-m12.html

http://www.brewershardware.com/Tri-Clover-Thermowells/

 

I havent read all this but IMO the safest way is to put the temp probe thats working with the pid to control temps directly at the rims tube exit near the element...
I do this.

I also have an analog thermometer mounted in a tee at the exit of my mashtun... when mashing the two are within a degree of each other once the liquid has recirculated all the way through the grainbed after passing through the rims...

Edit** after reading this thread it sounds like my method is identical to schematix's..

 

This is dangerous.... if something gets plugged the rims just keeps heating and burning the wort... this method can work with herms but is not ideal for rims. you can actually mash a lot of your wort at varying temps this way.

putting the controlling probe in the rims is the most accurate means of doing it

 

This dosent make sense though...(unless there some other problem with your system)
if your rims is heating the mash to 152 degrees and that wort is going directly into the MT and recirculating then after a few minutes at most they will be within a degree or two of each other... even with an uninsulated stainless pot in a very cold brew room (MY setup).... there is such a time delay in your setup your rims would be more likely to be constantly over and undershooting ...

I used your setup with my old herms system and remember how it worked. i curious to see pic of your setup to see what would cause your system to behave so differently than most (or all should)

 

you can get them on ebay or amazon as well...

http://www.ebay.com/itm/Boiler-Ther...756?pt=LH_DefaultDomain_0&hash=item4ad8b811dc

 

This is what I would suggest as well. An important part of this (that I hadnt considered on my system until reading this thread) is to control mash temps right at the input return to MLT. That covers any losses you may have in the tubing/plumbing from RIMS (or HERMS) to MLT.

I think Im going to see if I can easily adjust my system (right now I have sensor at HERMS outlet, then it goes through roughly 3 feet of tubing to MLT). I get about a 2 degree difference between PID reading and actual Mash Temp reading. I know this and adjust my PID up by 2 degrees but would be much simpler if the readings were balls on.

 

The downside with this setup if you get any type of stuck or slow flowing sparge the temp in your rims tube will continue to rise very quickly and scorch everything inside... I have a flowmeter and about 2-3 ft of line in my setup between the in port in my MT and the rims and my temps are always within a degree of my setpoint.... I think these losess are not what people make them out to be once everything comes up to temp.

 

All the concerns re; scorched wort makes me thankful that i spent the extra $ & went with a HERMS.

 

I also measure with a digital thermometer at the output of the mlt (cooler) as it enters the grant. Knowing the temp in and out validates the temp of the mash.

 

Good Point. If I had RIMS I would at the very least monitor temps inside of the RIMS tube to prevent scorching

 

Has anyone actually ever scorched wort? I'm starting to think it's a sibling of the mythical beast known as hot side aeration. With proper control of element heating and pump flow this isn't a likely scenario.

Good luck putting a probe inside the tube near the element. When you're not flowing, your super heated liquid layer is thin and is very near the element. That's a recipe for nuisance tripping. A flow meter or flow switch would be better suited to this purpose. Flow switches are tricky because they have a spring loaded piston that is essentially a grain catcher. Real flow meters are expensive. Augie uses a flow switch somewhat successfully, but i think he's still debugging it due to flow restriction it causes.

 

Or you could just put the temp probe near the element at the base of the rims at the exit point and still have the benefit of a rims setup over the slower herms...
The "concerns" are mostly based off of certain setups and their shortcomings.. with proper care and thought put into the setup they can operate just as safely as a herms and do step mashing or corrections much faster.

 

I scorched and ruined a couple batches due to a design flaw in my first homemade copper rims tube creating a small dead space at the base of my element where the flow was very weak and any debris could easily get caught up and scorch... Its a non issue with my new rims as checking the element after brewing shows I dont even get any type of buildup on it at all...

yes I could use my flowswitch as is now but since I use small 24v dc pumps the flow switch would restrict my flow down to about 1gpm.... not the direction I want to go... still looking for a lighter weight spring for the actuator in the switch. right now having the flow meter and being able to see the realtime flowrate does work just as well while im in the room...

 

What kind of flow rates are you aiming for? My mash wasn't happy recirculating that fast. And my rims rocket couldn't heat that volume fast enough to hit ramp set points so it was bouncing all over.

It's nice having a sight glass on the mash tun too. The level in the sight glass gives a pretty good indicator of how hard the mash is being drawn on. When i was going around 1gpm it went from 8G down to 4G in a matter of minutes. Drawing at half that rate it was steady around 7-7.5G for almost 2 hours.

 

You can step mash with a herms without the scorching concerns of a rims.

The two are not mutually exclusive.

 

well you seen my rims... (on my build thread) Its just a 25" 1000w straight cartridge heater... at 1.6gpm my rims pid maintains 152 degrees in a 67degree room with my uninsulated stainless MT at about 30-40% pwm duration... I suppose I could try it out and see how it performs with less flow... we are only talking .5GPM but the thing is that was my loss before taking the grainbed into consideration... with just water my flowmeter flows at about 2.4gpm through my MT and rims... with grain for a 10g imperial stout its down to about 1.5gpm... I fear the float switch restrictions may compound the loss on an already taxed pump...

 

Yes true,
and you can race a vw bug.... But if you compare the bug to a Porsche in the same race one will always lose the race since the vw wont ever perform like the other...

step mashing with a rims can be done in almost real time compared to a herms which has to heat all the hlt water to step temps on top of the mash ... and like I said before if the system is built correctly theres no concern of scorching with a rims.... dont get me wrong..herms is more foolproof.
I have used both have you? herms is the 80's volvo ...safe, solid, reliable, heavy and slow... rims would be the sportscar... greater risk?.. depends on the driver (and the engineering put into the car)..
its also like comparing a tankless hot water heater to a tank...

plus I can heat my sparge water up to temp while using my rims to maintain desired mash temps at the same time..all on a 30a circuit.

 

It never over or undershoots.
It is controlled by PLC Logic via a Unitronics controller with IO-PT4 temp modules.

It will hold my mash to 1 degree. The difference is that the element is heating up the wort directly and that tube can get hot so whatever temp it is reading is the temp of the wort right at the element and not temp in the TUN itself. Sure it is really close, but not nuts on. The RIMS I use is Bobby's from Brewhardware, the longer of the two. It does work just keeping it at the outset of the MT gave me better results.
I do agree with a comment earlier that the RIMS might be getting too hot and denature some enzymes, that is possible, so I might add a RTD in the tube to measure that and back off the settings for the PID a bit or alert me so I know I may need a smaller element.
I use a fairly large element in it and have no restrictions in-line after the element during the mash. (I do after when the spare starts but the element is off for that)
The temp off the TUN tells me the temp of the mash in its entirety, In the Tube it is a bit warmer, still valid this isn't rocket science, but my circulation is fairly fast as it is to help from scorching the wort. My PID routine uses an autotune program to set the variables of the values in the system so it has been tunes to not overshoot the temp or undershoot it.
But again, I will be adding it in the tube as well as another measure in case it gets too high in the tube. I have enough Inputs to do that.

I built and designed the system inspired by a large commercial system it may look familiar, but I built it all myself and automated the whole thing. These pics don't have some of the valves I added. These are older with manual valves at the spare valve but you can get a decent idea. I will take some newer ones soon.
The probe is in a T fitting under the spare valve (sparge valve now has a motorized valve in it)
The wort flows out of the MT, down through the T to another T with the probe, out to the front and through a valve that closes when sparking, another T that connect to the HLT (controlled by a motorized control valve) then through a 24V pump, then out the pump to the RIMS tube, then to of TUBE and through a camlok fitting in the top plate, up through silicon tube and into a fitting in the top of the MT.
I since added an autosparge to control sponge. This stays open fully during mash and engages during spare (to keep from plugging up the RIMS system.

All manual valves that you see have been replaced by electronic valves since these photos were taken. All controlled by the PLC
I have one valve that I left in after the pump but before the RIMS tube to fine tune the flow during spare if I need to slow it down

 

with the probe in the rims the rims will never heat the wort over the desired mash temp period.... the way you have it is subject to a controller having to learn to not over and undershoot temps and this would vary a bit with each grain bill... plus they have to "learn" to do this and make mistakes each time they do this when the environment varies...It all just something that can easily be simply avoided instead of all the additional compensation your plc is doing now... right now your rims starts out overshooting and then levels out slowly over time (unless your rims is really heating at small increments even while the plc sees low temps in the mash tun and tells it to fire at 100%)... my rims heats to the setpoint and no more...the fluctuations in temp are all below the setpoint until the equilibrium is achieved...

Nice setup BTW.

 

If something gets plugged and I have no flow my sensor detects that and shuts of the PID and alerts me

I have not had issues with plugging up but I have with something not working right, messing with the program and turning on a pump or opening a valve correctly, has stopped the flow and gave me trouble so a sensor helped that. It was only during debugging though

 

What sensor? I must have missed that your using a flow sensor.

 

My data point: The temp probe in my RIMS tube is about 2 inches from the heating element, liquid flows over the heating element then over the thermowell, then piped back on top the grain bed. In my case the return liquid at the mash tun is exactly same temp as the temp reading in the RIMS tube. When changing temps, the grain bed fairly quickly catches up to the same temperature as the RIMS tube.

From my experience I gotta agree with augiedoggy's points. Using temperature readings for PID input from anywhere other than as close as possible to the heating element exposes you to potential (unnecessary?) risks.

Disclaimer: New RIMS tuber here, only used a hand full of times. I haven't tried using temp readings anywhere else as the process control.

(edit) I wouldn't mind playing with using temp readings elsewhere in the system so long as I always also had that temp reading at the heating element and had a way to use that to establish safety limits.

 

I use an Omega flow meter inline

guess I did miss that part.

 

Lots of good info.
Not sure if I will have RIMS when I start brewing, but planning the panel for future expansion.

I am planning a simple RTD on the bottom valve of the mash tun with a read out screen on the panel. When I add RIMS in the future the RTD would be in the RIMS tube and control the PID. With this combo I should be able to dial in temp of the PID to the desired output on the mash tun valve.

The brew pots I plan on buying have a SS thermowell on them. When I screw in my RTD won't there be airgap. How does this work for temp accuracy? Is this normal?

 

I have never used a RIMS.. I have no need for it..

 

But this conversation is proof otherwise...
Afterall, your making comments and giving advice about something you just said you have no experience with... If you did It have some experience it would certainly add to the credibility of your comments right? I wouldn't consider the knowledge useless here or something you have no use for...

I went with a herms system first because I had read all these negative comments about rims but the thing is the truth it that most who have tried both systems that were designed correctly dont go from a properly designed and working rims system to a herms. more go to rims for faster step mashing but even those numbers arent high... If it works great people dont generally mess with it unless they are engineers at heart..

My herms did not perform well... I made some big mistakes when building it.. even after correcting most of them I was not impressed with it... so I made a cheap $50 rims which worked waay better but also had some design flaws that I had to fix. Now I have a setup that works very well for me.. Are their better setups ? sure I bet there are but like you I'm very satisfied with mine..
both have strong points... I'm sure someone can address the efficiency issues with herms by using a smaller hlt or more elements just as things can be done to completely prevent any scorching with rims. for my setup, resources and needs the rims was a better fit.
and you cant get any more precise in controlling temps than actually controlling the temp at the source of the heat output. everything else has delays and has to "learn" to deal with that... if someone is really losing more than one degree just going from the rims to the MLT then somethings wrong... and if the happens you simply set the temp one degree higher on the rims right? problem solved... and the wort NEVER gets hotter than that one degree differential... option 2, insulate the hose or line to the MT (again I brew in a cold room with an uninsulated MT and I dont see any drop)

 

Augie you nailed it here.

 

The thread is proof otherwise that I have a need for a RIMS system?

I wouldn't have a say so in that?

I never said that a HERMS system was superior to a RIMS system. I just agreed with your point that a RIMS, if improperly designed & lacking the necessary fail safes WILL SCORCH WORT. A HERMS does not have these concerns.

You also implied that step mashes are more practical (because of speed alone) with a RIMS than a HERMS.

This is a matter of preference moreso than anything else. My system can do steps rather quickly. I outlined why this was the case. (insulated MLT, 50' 1/2" coil, and a auxiliary pump to eliminate stratification.

So back to my point. I have never tried a RIMS system because I don't need one. It is frankly that simple.

You switched to RIMS because your HERMS did not achieve what you wanted it to do.

Mine does. No big deal.

Go ahead & quote me and proceed to continue arguing with the brick wall.

This argument is just as applicable to a HERMS system. Not that you were neccesarily trying to distinguish the difference between the two..

 

One major difference with HERMS being that it's indirect, slower, heating so it eliminates the risk of scorching or the possible enzyme denaturing that we have with RIMS. I think temp probe placement on a HERMS system would be much more flexible or forgiving.

(On a side note, is enzyme denaturing actually a problem if we're just talking about a couple cups of wort inside the rims tube out of a 5 gallon batch?)

[Edit]
Ah, you've edited since I posted this! Almost makes this post seem redundant... At the risk of looking dumb I'll leave it here any way. I still feel that probe placement for process control between HERMS and RIMS is apples and oranges.

 

I agree if for only the safety concerns & risk of scorching the wort....

There was pretty wide range in HLT / MLT temp variation because of how & where the losses were being measured when I first set mine up.

I tried measuring the MLT internal temp with a 6" probe & then also as the wort was exiting the MLT & both caused the HLT to heat to +8/10 degrees of where I wanted the mash temp... Obviously trying to compensate for heat losses.

The absolute best place in my system was as the wort is returning into the MLT.

For the sake of reference though, measuring at the MLT return results in my HLT to heat @ +1 to 2 degrees of the mash target.

It is pretty close. Certainly close enough for my needs.

One more thing about ramp efficiency too. Wort flow rate & HEX efficiency are key. I know this is stating the obvious. Had I only invested in a 25' 3/8" coil & a 12v circulation pump, I have no doubt that I would have been very frustrated with it's effectiveness.

It is a $ trade off for sure. RIMS is cheaper, that I will agree with. But that does not necessarily make it superior & certainly not safer.

EDIT: I agree that where you measure wort for the sake of the PID can be much more varied than with a RIMS..

For the sake of precision though.. Measure the wort at the HLT exit/MLT inlet is just as precise as measuring a RIMS at it's exit.

Neither tell you the exact temp of the grain bed though. You need more points of measurement to determine that.

 

Come on... you really didnt understand what I was saying? Your comments in this thread and admission that you have no real experience with one are proof that your unqualified to state "facts" as you see them about a rims setup... I'm trying to say if you were to actually see and use a rims setup you may likely change your views about them a bit.
Argue with a brick wall? is that like "talk to the hand" or something like that....lol your answering me so I dont see how I'm argueing with myself... besides im not arguing Im discussing your lack of knowledge about the arguments your were basing comments on thats all.

I think A herms system is hands down cheaper to implement than a rims... all you need is a 50 ft coil and a way to keep the water agitated in your hlt for herms...everything else you would likely have anyway ..that is unless you lack temp control in your hlt. otherwise its one less eheating element and controls for that element thats needed... Just like a rims the herms that is not designed correctly wont perform well either. True you wont scorch the beer but you wont have the beer your trying to make either.
Is it just me or does it seem like what your saying now has shifted course a bit from your earlier comments