HERMS Temp Probe Location

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SAMPLER

SAMPLER

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Setting my HERMS stand and control panel. I'm going to using 2 PID and a single element. I'm wondering what is the best it recommended locations I'm the HERMS and MT to set up my temp probes for the most consistent and accurate readings. Thank you for your input.

Cheers
 
I have mine on the return line just before the liquid goes into the mash tun. I find that the temperatures at the return are about two degrees lower than the temps in the mash tun.
 
Runningweird: Did I read that right? The temp at the return reads 2 degrees _lower_ than in the tun?

Wouldn't the hottest location be in the HERMS coil and the coolest be in the Tun itself? Just checking my thinking.
 
So with one location coming out the herms return to the MT where should I put the second temp probe for the other PID? Directly connected to the MT?
 
Having one port at the bottom of the mash tun and one at the top might be beneficial. That way you can read the temperature of the recirculated mash right after going through your HERMS coil, as well as the mash that has been in the tun for the longest period of time. I'd guess that you see a 1-2 degree differential when stopped, and maybe more like a 2-3 differential while recirculating.

Cheers!
 
i have two, one installed at the temp port on my hlt and one on the tun out of my mlt.
 
I have the probe at the return on the MT as well. We previously had it at the MT out but putting it at the return is much more accurate.
 
I agree with the probe on the return line to monitor mash temp. I think i should put another probe in the HLT to measure water temp for use such as strike temp or sparge temp.

The question i have is....Do most use the herms to increase mash temp to mash out instead of sparging?
 
I use the HERMS to raise mash temp to mash out as I heat my sparge water. Meanwhile I also direct fire my MT to reduce lag time.

I hit 168 and start my 10 min timer on mash out vorlauf, and then add non mashables to the mash. (Crystals, chocolates, patents, roasted, etc.)
 
luhrks said:
One in the HLT to regulate it. The other at the HEX Out.
Click to expand...

Yea this is what I would do with two PIDs. I manage to get by with one PID and a sensor in both locations that I can switch to, but it’s not very conducive to total control. I generally keep the control sensor on my HERMS coil, but sometime that causes overheating in the HLT since I use a relatively short coil and dont get 100% efficient heat exchange (HLT temps sometimes run 5-10 degrees higher than HERMS coil output). So I need to anticipate that and either cut power to the HLT early or just add some cold water to bring it down to the right sparge temp. Its a pain but not unbearable - I dont nitpick over a few degrees when sparging anyways, as long as its in the 160s-170 I am good with it. When mashing as long as I am controlling the HERMS output temp I know my mash is at the right temperature, I dont care what my HLT temp is at.

luhrks said:
I use the HERMS to raise mash temp to mash out as I heat my sparge water. Meanwhile I also direct fire my MT to reduce lag time.

I hit 168 and start my 10 min timer on mash out vorlauf, and then add non mashables to the mash. (Crystals, chocolates, patents, roasted, etc.)
Click to expand...

Sorry to threadjack a bit, but whats your reasoning behind not adding the ‘non-mashables’ until mash out is completed? It is a MLT volume thing?
 
Reduced astringency/bitterness.

It's the difference between a porter/stout being drinkable in 20 days vs 120. ;)
 
If it were me, and it will be soon...lol

Hex out and MLT.

My thinking is this, if you are controling the mash temp at the coldest part of the mash, then you are over temp at the top side. If you are controling mash temp at the HEX out then you can never over shoot the temp.

Having said that, I am sure either way is fine, if you are doing a continous recirq, then grain bed and wort in the mash tun will reach a steady temp and you should only see a small difference for a short amount of time.

Tim
 
I too have heard that the HEX out is a more reliable indicator of the mash temp, although I personally have no evidence to support it.

I don't see the need for two PID's or temperature probes. Can someone please enlighten me? This is the way I see it...

For strike water:
connect water out to pump, pump out to HEX in, HEX out to water in. Input SP, prime pump, turn on pump, turn on element. This will give you the "Real" temp of the strike water, and the PID will control it's temp until it reaches SP. Then transfer desired volume, turn off element, turn off pump, mash in.

For mash temp:
Change SP, put MT out to pump in, pump out to HEX in, HEX out to MT return. Turn on pump, turn on element.

This allows you to use the same location and one PID to control both strike and mash temp. For mash out/sparge, you can just change SP, stop when it reaches it, and reconfigure to the "Strike" set up (this will also clean the coil now that hot water is rinsing it). Now SP can be changed to sparge temp, and repeat.

For the boil, couldn't you just use an element hooked up to a switch and pot? reduce pots resistance until boil is reached then reduce.

Am I missing something? Or will this produce less than favourable results?
Thanks, and sorry for the thread jack... this 2 PID just seems unecessarily complicated
 
JayMac said:
I too have heard that the HEX out is a more reliable indicator of the mash temp, although I personally have no evidence to support it.

I don't see the need for two PID's or temperature probes. Can someone please enlighten me? This is the way I see it...

For strike water:
connect water out to pump, pump out to HEX in, HEX out to water in. Input SP, prime pump, turn on pump, turn on element. This will give you the "Real" temp of the strike water, and the PID will control it's temp until it reaches SP. Then transfer desired volume, turn off element, turn off pump, mash in.

For mash temp:
Change SP, put MT out to pump in, pump out to HEX in, HEX out to MT return. Turn on pump, turn on element.

This allows you to use the same location and one PID to control both strike and mash temp. For mash out/sparge, you can just change SP, stop when it reaches it, and reconfigure to the "Strike" set up (this will also clean the coil now that hot water is rinsing it). Now SP can be changed to sparge temp, and repeat.

For the boil, couldn't you just use an element hooked up to a switch and pot? reduce pots resistance until boil is reached then reduce.

Am I missing something? Or will this produce less than favourable results?
Thanks, and sorry for the thread jack... this 2 PID just seems unecessarily complicated
Click to expand...

That seems reasonable, although the second PID could just be used as a "dumb" thermometer on the output of the MLT so you can see the actual mash temp. Or just use a thermometer and use the second PID in manual mode for the BK.
 
jeffmeh said:
That seems reasonable, although the second PID could just be used as a "dumb" thermometer on the output of the MLT so you can see the actual mash temp. Or just use a thermometer and use the second PID in manual mode for the BK.
Click to expand...


Fair enough. I guess installing a bi-metal thermometer could serve the same purpose as the 'dumb' PID.

And wouldn't a PID with manual mode be a fancier way of using the pot as described in my previous post?

Thanks!
 
JayMac said:
Fair enough. I guess installing a bi-metal thermometer could serve the same purpose as the 'dumb' PID.

And wouldn't a PID with manual mode be a fancier way of using the pot as described in my previous post?

Thanks!
Click to expand...

Yes on both counts. FYI, Kal's panel uses 3 PIDs the way I described, an I like the aesthetic of three PIDs in a row. But what do I know, I'm just a clueless BIAB guy. :)
 
I should also add that there is one advantage the PID in manual mode has over the potentiometer for the boil kettle. You can set the setpoint to 208F or thereabouts and walk away without worrying about a boilover, then when the alarm sounds or before, go back and set it to 100% manual, then lower the manual % when you reach a boil.
 
JayMac said:
I too have heard that the HEX out is a more reliable indicator of the mash temp, although I personally have no evidence to support it.

I don't see the need for two PID's or temperature probes. Can someone please enlighten me? This is the way I see it...

For strike water:
connect water out to pump, pump out to HEX in, HEX out to water in. Input SP, prime pump, turn on pump, turn on element. This will give you the "Real" temp of the strike water, and the PID will control it's temp until it reaches SP. Then transfer desired volume, turn off element, turn off pump, mash in.

For mash temp:
Change SP, put MT out to pump in, pump out to HEX in, HEX out to MT return. Turn on pump, turn on element.

This allows you to use the same location and one PID to control both strike and mash temp. For mash out/sparge, you can just change SP, stop when it reaches it, and reconfigure to the "Strike" set up (this will also clean the coil now that hot water is rinsing it). Now SP can be changed to sparge temp, and repeat.

For the boil, couldn't you just use an element hooked up to a switch and pot? reduce pots resistance until boil is reached then reduce.

Am I missing something? Or will this produce less than favourable results?
Thanks, and sorry for the thread jack... this 2 PID just seems unecessarily complicated
Click to expand...

What you're missing is that during the mash you'll need to fire your HLT to raise/maintain mash temp. Judging that off the HEX-O isn't a huge problem per se, but you run the risk of "chasing your tail" with temps. During ramp ups, or steps you need to monitor both the HEX-O and HLT temps because there'll be a lag between what the HLT temp is and what gets transferred to the HEX. Unless you monitor both there's the potential for a situation where you've heated the HLT way over the ideal set point before the wort in the HEX catches up. (Oh crap! I can't sparge, I'm 190!)
 
jeffmeh said:
I should also add that there is one advantage the PID in manual mode has over the potentiometer for the boil kettle. You can set the setpoint to 208F or thereabouts and walk away without worrying about a boilover, then when the alarm sounds or before, go back and set it to 100% manual, then lower the manual % when you reach a boil.
Click to expand...

Point well taken, it does make the system more automatic and fool proof!
 
luhrks said:
What you're missing is that during the mash you'll need to fire your HLT to raise/maintain mash temp. Judging that off the HEX-O isn't a huge problem per se, but you run the risk of "chasing your tail" with temps. During ramp ups, or steps you need to monitor both the HEX-O and HLT temps because there'll be a lag between what the HLT temp is and what gets transferred to the HEX. Unless you monitor both there's the potential for a situation where you've heated the HLT way over the ideal set point before the wort in the HEX catches up. (Oh crap! I can't sparge, I'm 190!)
Click to expand...

I was thinking about that. Obviously, this would be less of a problem if a copper HEX is used due to its higher thermal conductivity (wrt stainless steel).

When you say monitor, do you mean have 1PID, and a thermometer? Or 2 PIDs, set HEX out to desired mash temp, and set HLT temp to a SP which you don't want to over shoot? That is helping me see the value of a second PID. If you know about PID theory, I guess we can say that by not having a second PID to put a limit on the HLT temp, we are "increasing Kp" and "decreasing the time constant"- this increases overshoot and oscillations about the mash SP.
 
1 PID, 2 PID 3 PID, as many as you can fit in a box PID...all in what you want.

No right or wrong number really. Mine will be a single PID to start, but I will move to at least 2 at some point..I like to read pretty numbers. You can also use the PID in the HLT to define a SP and not over shoot your mash that way. If you run AT, it should learn the ramp times, and correct however...

Tim
 
kpr121 said:
I generally keep the control sensor on my HERMS coil, but sometime that causes overheating in the HLT since I use a relatively short coil and dont get 100% efficient heat exchange (HLT temps sometimes run 5-10 degrees higher than HERMS coil output).
Click to expand...

Can you tell me about your coil? Material, OD, ID, and length. Mash recirc flow rate will also have something to do with this, but that might be hard to quantify. Do you recirc your HLT water? I'm designing a HERMS system now and want my coil out temps to be as close to my HLT temps as possible.
 
kevink said:
Can you tell me about your coil? Material, OD, ID, and length. Mash recirc flow rate will also have something to do with this, but that might be hard to quantify. Do you recirc your HLT water? I'm designing a HERMS system now and want my coil out temps to be as close to my HLT temps as possible.
Click to expand...

Its about 15 feet of 1/2 od (3/8? Id). I recirc my hlt water with a dedicated pump at all times. My mash recirc rate is usually pretty high and I use 6 ft silicone hoses so a total of approx 18 ft exposed silicone probably looses some heat too.

If I were you I'd go with 25 feet copper at least if your worried about it. Or go with whatever you have and once you learn your system it won't much matter.
 
With a PID in the HEX exit I assume the temp of the exiting wory is controlled by the ball valve? If there is a PID in the HLT is this controlling the element do ensure the overall temp stays within a reasonable sparge temp?

A little help with the explanation would be much appreciated.
 
kpr121 said:
Its about 15 feet of 1/2 od (3/8? Id). I recirc my hlt water with a dedicated pump at all times. My mash recirc rate is usually pretty high and I use 6 ft silicone hoses so a total of approx 18 ft exposed silicone probably looses some heat too.

If I were you I'd go with 25 feet copper at least if your worried about it. Or go with whatever you have and once you learn your system it won't much matter.
Click to expand...

Thanks. I'm planning on 40' of 1/2", 0.020" wall stainless, so I think I'll be OK!
 
SAMPLER said:
With a PID in the HEX exit I assume the temp of the exiting wory is controlled by the ball valve? If there is a PID in the HLT is this controlling the element do ensure the overall temp stays within a reasonable sparge temp?

A little help with the explanation would be much appreciated.
Click to expand...

Not sure what you mean here, but I will do my best to fill in...as I will do it

With the PID using the HEX out temp, you inmput your setpoint(Mash temp) the PID then used that to drive the element in the HLT, raising the temp of the HLT water to make a change in the wort temp as it moves through the HEX.

HEX construction, Flow rate through the HEX, exposed tubing between the HEX and MLT will all factor into the rise and fall of the wort temp as it moves through the system.

Trial and error will tell you how you need to set your Setpoints to get the mash temp you desire, factoring in heat lose and other things.

Hope that helps.

Tim
 
SAMPLER said:
With a PID in the HEX exit I assume the temp of the exiting wory is controlled by the ball valve? If there is a PID in the HLT is this controlling the element do ensure the overall temp stays within a reasonable sparge temp?

A little help with the explanation would be much appreciated.
Click to expand...

After reading through this thread I was wondering the same thing. I guess you could set up the PID to turn the recirc pump through the HERMS on and off.
 
MX1 said:
Not sure what you mean here, but I will do my best to fill in...as I will do it

With the PID using the HEX out temp, you inmput your setpoint(Mash temp) the PID then used that to drive the element in the HLT, raising the temp of the HLT water to make a change in the wort temp as it moves through the HEX.

HEX construction, Flow rate through the HEX, exposed tubing between the HEX and MLT will all factor into the rise and fall of the wort temp as it moves through the system.

Trial and error will tell you how you need to set your Setpoints to get the mash temp you desire, factoring in heat lose and other things.

Hope that helps.

Tim
Click to expand...

I still don't see the need of a separate PID in the HLT then? What exactly is it controlling? Maybe my switchable setup where I can change which rtd probe my single PID is reading is as good as I'm going to get. The other one goes to a cheap digital temp readout I got on eBay.
 
kpr121 said:
I still don't see the need of a separate PID in the HLT then? What exactly is it controlling? Maybe my switchable setup where I can change which rtd probe my single PID is reading is as good as I'm going to get. The other one goes to a cheap digital temp readout I got on eBay.
Click to expand...

I was right with you an hour ago.

The PID in the HLT is usually used to a) give a temp reading b) sets the upper limit for the HLT for step mashes.

E.g you want to go from 152 to mash out. You change the SP to 165 ish. The heater goes on full blast. By the time the wort reaches 165, HLT is probably 180+. By using a PID, you can set the HLT to 170F, therefore reducing overshoot on your mash.
 
kpr121 said:
After reading through this thread I was wondering the same errthing. I guess you could set up the PID to turn the recirc pump through the HERMS on and off.
Click to expand...

Good point but i don't see this helping the chances of overshooting possible sparge temps. Too bad the second PID couldn't over ride the first and shut off the element before it over shoots the temp.
 
There will always be a difference between the HLT water temp and what comes out of your HERMS. In fact, the greater the delta, the faster your mash temp rises. So yeah. You want to monitor your HLT and keep it at a set point because it will get there prior to your wort.

If you're step mashing it can be problematic to go over temp, but you can solve it by cutting flow or increasing flow.

If you're heating sparge, you're a bit FUBAR. ;)
 
you dont NEED one, some people just WANT one...do Need a thermo to boil, nope....but how many of us have them
 
JayMac said:
I was right with you an hour ago.

The PID in the HLT is usually used to a) give a temp reading b) sets the upper limit for the HLT for step mashes.

E.g you want to go from 152 to mash out. You change the SP to 165 ish. The heater goes on full blast. By the time the wort reaches 165, HLT is probably 180+. By using a PID, you can set the HLT to 170F, therefore reducing overshoot on your mash.
Click to expand...

So is the PID in the HLT controlling the element or is the PID in the HEX output?
 
SAMPLER said:
So is the PID in the HLT controlling the element or is the PID in the HEX output?
Click to expand...

You can do either one, but you still need the second PID to make it reach SP effectively.

If you use the HLT, you don't want to set it to srt point (SP), as this will take a really long time to hit your temp. You'd likely put it a few degrees above, then once the HEX out reaches mash temp, drop the HLT down to mash temp as well (or maybe a degree higher).

You will need both PIDs to make sure you hit your mash temp as fast as possible, with the least amount of overshoot as possible.
 
so I shorted that answer.

You can set it up to control the HLT water for sure. You have to learn your off sets though. Figure the difference between HLT temp and mash temp, then program that into your setpoint
 
JayMac said:
I was right with you an hour ago.

The PID in the HLT is usually used to a) give a temp reading b) sets the upper limit for the HLT for step mashes.

E.g you want to go from 152 to mash out. You change the SP to 165 ish. The heater goes on full blast. By the time the wort reaches 165, HLT is probably 180+. By using a PID, you can set the HLT to 170F, therefore reducing overshoot on your mash.
Click to expand...


So whenever one of the two pids hit their respective set point, the element shuts off? That still doesnt seem like its worth having two pids.
 
I'm planning to use gas burner to reach my starting temp and then rely on the PID and element to maintain and raise for step mashing.
 
kpr121 said:
So whenever one of the two pids hit their respective set point, the element shuts off? That still doesnt seem like its worth having two pids.
Click to expand...

again, you dont need 2.

I will not be using 2, just 1, all about choices....:ban:
 

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