HERMS Help

[rollinred]

Just bought a chugger pump and cam lock setup. Realized I had 25' of leftover copper coil and got to thinking that I could be just a couple steps away from a HERMS rig. I'm wondering how you all fire you element to keep the mash stable.

I would like to keep my rig simple for now and really have no money left to spend but think I need more parts to make a HERMS system work right.

Currently I have a 10 gal Blichmann that serves as my HLT and BK with a 5500 watt element. I was planning on making a lid that holds the HERMS coil and a stirrer motor that would drop in place during the mash and be easily removed for boil.

My main question is that of how to control the temp for the mash with constant recirc. Do I need to buy another RTD sensor and mount near the output of the HERMS coil to control the PID or can I use what I have and simply let the mash temp stabilize and adjust the HLT temp setting accordingly?

How hot does your pump run? My new chugger seems to be getting pretty hot, not burning but certainly not comfortable to hold your hand on, and that was only with 10 minutes of run time. Maybe this is normal but it just has me nervous for running recirculation during the entire mash.

 

[BadNewsBrewery]

If you just want to add a HERMS coil and use your existing stuff, it sounds like you have most of what you need. You could use an analog thermometer to figure out what your mash temps are compared to your HLT temps, and once you figure out the temperature differential, you could just adjust your HLT temps and know what the mash tun is at.

How hot does the pump run? I suppose a lot of that has to deal with how hot the liquid you're pumping is. If you pump cold water, I can imagine the pump won't be as hot as if you're pumping near boiling wort. These are rated for high temps though so I don't think you should stress.

-Kevin

 

[biertourist]

I'm still trying to figure out my HERMS system myself but it sounds like you could manually recirculate until you reach temp like BadNewBrewery has suggested OR you could get another RTD and plug it into the mashtun (not the HERMS coil output) and then let the PID controller up the temp in the HLT until the mash hits your next targeted temp step.


-Personally I don't want the water in my HLT to get above 176F as I'm afraid of the water out of the HERMS coil getting too hot and damaging my enzymes. (Although typically you'd be step mashing on high protein malts which means high enzymatic power so maybe it's not such a big deal...) -Its certainly not a big deal when you're trying to go to mash out temps; but from a protein rest to your Saccrification rest is when I'd be most concerned.



Adam

 

[audger]

-Personally I don't want the water in my HLT to get above 176F as I'm afraid of the water out of the HERMS coil getting too hot and damaging my enzymes.

this is the exact reason why you DO want to have the temp probe in the output of the HERMS and not in the mash tun. that way it wont matter what the HLT temp is; the HERMS output will never get above the set temp. and as long as your flow rate is adequate enough, the mash temp will reach equilibrium with the set temp automatically.

a function of the flow rate and the amount of heat (watts or BTUs) you are able to supply determines how quickly equilibrium is reached.

its helpful (read: but not necessary) to also monitor the mash temperature, but that should not be the input for your PID controler.

 

[kal]

The mash will never get hotter than the HLT water if recirculating the mash through a HERMS coil in the HLT. It's not possible.

So here's how I do it:

I have 3 kettles:

Boil
MLT
HLT

There's a temp probe on the wall of the boil kettle, but we'll ignore this as it's separate/not relevant.

On the MLT and HLT I have temp probes on the kettle outputs like this:

There's a HERMS coil in the HLT used to heating the mash as required.

The HLT temp probe controls the HLT water temp through a PID that fires the heating element in the HLT. It indirectly heats the MLT too through the HERMS coil.

The MLT temp probe controls nothing. It simply displays the temp on the MLT PID so that we know what the mash temp is at. Putting the probe on the output of the kettle ensures that the entire grain bed is AT LEAST at that temp since it's the last point in the kettle essentially.

After mashing in, the mash fluid is circulated through the HERMS coil in the HLT to maintain temperature. Whenever I increase temp (step mashes or mash out, or even initially mashing in) the mash temp lags behind the HLT water temp so having the MLT temp probe on the output of the HLT shows me how fast the MLT heats up. It shows me how far it lags behind. The bigger the grain bill, the slower it is for the mash to heat up.

For example, take a look at this picture:

The Hot Liquor temp has now reach my mashout temp of 168F (after heating for 15 minutes) but the Mash temp is still only at 164F. I want to wait until the mash hits 168F too before I start sparging to make sure I've denatured the enzymes correctly. If I had the mash temp probe on the HERMS coil output, I'd have no way of knowing what the mash temp is at.


Putting a temp probe on the output of the HERMS coil will simply show you the temp of the HLT which isn't all the useful. This is what I used to do but that temp was always the same as the HLT temp so I moved that probe to the output of the MLT. Much more useful.

I have some videos on my brew day step by step article that show how much the mash temp lags behind temp changes I make to the HLT.

Kal

 

[moffatt163]

+1 for kal's post. I would find a probe immediately after the HLT not nearly as useful as a probe low in the grain bed or below the false bottom.

 

[rollinred]

Kal,

I think I understand what you are saying but I would like to clarify it. What I think is getting a little lost here is that I am simply looking to see which RTD/temp sensor people are using to control the heating element. The way I see it, you could do it from 3 different places.

1. From the HLT probe and simply monitor mash temps
2. From a probe in the output of the HERMS coil
3. From a probe directly in the MLT

Every one of these would work but the simplest for a guy like me that wants a dual purpose HLT/BK is to simply use the RTD already in the HLT to control the heat. This would allow me to get away with using the equipment I currently have.

Using either the MLT or the output of the HERMS would mean I don't need to have another thermometer to monitor the MLT temp, but since I already have one I would just throw it in and adjust the HLT temp to keep a constant temp in the MLT.

I am surprised how little info I have found on this. I know it is out there but I can't seem to find a consensus or the benefits of doing one or the other.

 

[Yooper]

1 works for me, if I understand what you're saying there.

In my system, my HLT is set with a PID. I "lose" three degrees- that is, the mash temperature is three degrees cooler than my set temperature. If I want to maintain a mash temperature of 152, my HLT is set at 155.

It always works for me.

Others may find their systems have different needs, so I hate to say "it depends", but it really does depend on each individual system.

I have a little stirrer on a board that I have in my HLT- it could be removed if I also used it as a BK, but I have a dedicated HLT.

 

[biertourist]

Rollinred,

I'm with you I've had a very difficult time finding good discussions on this subject.
Yooper, The information on the 3 degree temp difference is quite useful. Do you typically do 5 or 10 gallon batches? Is your MLT insulated?


I like the idea here. (Control and set the temp in the HLT and just MONITOR the MLT temp.) When I want to step I just set the HLT PID to a couple of degrees above where I want the mash to be and wait.

I'm sure the first brew through the HERMS will be hectic but it seems pretty simple once you get to know how your own system responds. (I'm going to go with temp probes and thermometers everywhere the first time through.)


Adam

 

[rollinred]

Thanks Yoop! That is exactly what my question was.

What I am going to do is build a lid for my HLT that will hold the HERMS coil and a stirrer motor. This whole lid will just lift off when it's not in use.

I simply was not understanding which way people controlled the element, or rather, which temp probe they used to control the HLT. I would rather not purchase another RTD and find a way to mount it. Using what I have currently will be best.

 

[kal]

I like the idea here. (Control and set the temp in the HLT and just MONITOR the MLT temp.) When I want to step I just set the HLT PID to a couple of degrees above where I want the mash to be and wait.

Exactly. That's my recommendation and what I do. Of course, everyone's needs are different so feel free to do what feels right to you. Oddly enough, my HLT and MLT both measure the same temperature (no differential and both probes have been calibrated). This makes it easy as if I want the mash to go up to 155F, I set the HLT PID to 155F.

I'm sure the first brew through the HERMS will be hectic but it seems pretty simple once you get to know how your own system responds. (I'm going to go with temp probes and thermometers everywhere the first time through.)

Use water only the first few times to just see how the system behaves. It doesn't have quite the same thermal mass as a bunch of grain but it's still a good test. It lets you get the kinks ironed out the first few times. I remember my first few batches were a bit hectic as I was measuring/checking/verifying everything in a bunch of spots wondering what was going on.

At the end of the day you'll still make beer and the things you think may be huge variables will likely prove to be minor. As Charlie would say, RDWHAHB!

Good luck!

Kal

 

[Yooper]

Rollinred,

I'm with you I've had a very difficult time finding good discussions on this subject.
Yooper, The information on the 3 degree temp difference is quite useful. Do you typically do 5 or 10 gallon batches? Is your MLT insulated?


I like the idea here. (Control and set the temp in the HLT and just MONITOR the MLT temp.) When I want to step I just set the HLT PID to a couple of degrees above where I want the mash to be and wait.

I'm sure the first brew through the HERMS will be hectic but it seems pretty simple once you get to know how your own system responds. (I'm going to go with temp probes and thermometers everywhere the first time through.)


Adam

Yes, no, yes.


Just kidding!

My mlt is NOT insulated. It's a keg, and I do 10 gallon batches. I preheat it with 180 degree strike water, and let it cool to 164ish (my usual actual desired strike temperature). It hold temperature amazingly well that way (I brew indoors), but the HERMS ensures steady temps especially after 15 minutes in or so.

I no longer even have to monitor the temperature of the mash, beyond checking it once I mash it to ensure thorough mixing and then once in a while if I feel paranoid.

I can ramp to 168, easily, by just changing the PID to 171. I have a 5000 w element in the HLT so it's within 10-12 minutes. I normally run the HERMS fairly slow during the mash, to just hold the temperature, and then run faster for the mash out.

It takes a few times with your system, but I'd recommend monitoring the temperature and times and recording it at first just so you know what to expect. After that, it's nearly automatic.

One thing that still amazes me- my wort is crystal clear within about 30 minutes after mashing in. It simply runs clear so quickly. I get an amazing hot break, a very big cold break, and clearer beer than ever. I blame it on the HERMS.

Here's a cream ale I'm drinking right now. No filtering, just plain ol' HERMS and primary only (10 days). (There is some condensation on the glass- it's hot in the UP tonight!) I think it's the super clear wort from the HERMS, and the tons of break material.

 

[rollinred]

Wow, this discussion got where it needed in a hurry. Thank you! Thought after the first few days it wouldn't get anywhere but lost.

I don't know 'bout you Yoop, but my Michigan blood can't take this heat. I'm ready to see some white stuff in the air. Mind me asking where it is you call home? Not to be a stalker or anything (that beer might be worth it though), I just love it up in the UP.


I guess I'm going to start putting this thing together though. I should have thought more in to this before because I just got done with a full cam lock setup and now I'll be $30 plus in shipping costs with another order

 

[sar_dog_1]

Would it make sence to set your hlt probe in the mlt output? That way if you want your mt to be 154, then the hlt will heat water automaticly to the unknown temp it needs to be to hit your mt mark. I have never brewed this way but after reading this post it kinda makes sence.

 

[Yooper]

Wow, this discussion got where it needed in a hurry. Thank you! Thought after the first few days it wouldn't get anywhere but lost.

I don't know 'bout you Yoop, but my Michigan blood can't take this heat. I'm ready to see some white stuff in the air. Mind me asking where it is you call home? Not to be a stalker or anything (that beer might be worth it though), I just love it up in the UP.


I guess I'm going to start putting this thing together though. I should have thought more in to this before because I just got done with a full cam lock setup and now I'll be $30 plus in shipping costs with another order

I"m in the central UP- and it has been very hot here this week. I don't like white stuff either, though! We go to south Texas in late January for a couple of months to get out of the cold. As I get older, I seem to have a very narrow temperature range- I'd like it 75 degrees, all the time.


Before you order again, try to plan it out all to avoid another shipping charge if you can! I've done that myself, and had to buy just a couple of little things. McMaster-Carr charged actual shipping, so it wasn't too bad, but it seems like I'm always forgetting something.

 

[jeffmeh]

Yooper, out of curiosity, does your mlt temp ever catch up to your hlt temp (even slowly), or have you observed that it gets to within 3 deg F and stops?

 

[Yooper]

Yooper, out of curiosity, does your mlt temp ever catch up to your hlt temp (even slowly), or have you observed that it gets to within 3 deg F and stops?

No, never. It's always 3 degrees lower than my HLT temperature, once it equalizes.

 

[jeffmeh]

No, never. It's always 3 degrees lower than my HLT temperature, once it equalizes.

I find it interesting that Kal's system equalizes with the HLT output and MLT output at the same temperature, yet your is 3 degrees different. No wonder this is not an "exact science," lol.

 

[kal]

This one has confused me too. Both my HLT and MLT probes are calibrated and show the same temperature when I first turn on the control panel (69F in the picture below):

Then when I mash the two also agree:

In this case I set the HLT PID to 149F and eventually the mash PID also shows the same temp. In the picture above, there's 3:30 left to go in a 90 minute mash.

I think it has to do with the fact that I use good pumps and recirc at 100% speed, and the silicone hoses I use are thicker walled 7/8" OD instead of the usual 3/4" OD that most people use, and no longer than needed (?):

I'm really not sure! I've often pondered this question but without being able to see someone's setup up close and figure out why, it's a bit of a guessing game.

Kal

 

[Bobby_M]

I would always expect some delta due to fact that heat is being radiated out of the mashtun and being added to the HLT water. Certainly the speed of recirculation plays into it, as well as the heat transfer rate in the coil itself.

 

[jeffmeh]

I would always expect some delta due to fact that heat is being radiated out of the mashtun and being added to the HLT water. Certainly the speed of recirculation plays into it, as well as the heat transfer rate in the coil itself.

Now you're trying to make it into an exact science, lol. Actually, it's just physics, so if we compared two specific systems we should be able to explain the varying behavior.

You nailed the basic variables: heat loss in vessels and hoses, heat transfer rate through the coil, and turnover rate through recirculation.

I'm willing to bet that with some insulation and a high enough flow rate one could get a system to equalize at or close to the same temperature.

 

[kal]

As Bobby said there will always be some loss - it's inevitable. The PIDs only show 1 degree F increments so I could be losing 0.9F or less so it doesn't show up. It could be too that the RTD probes are not 100% linear in their response. I should go and recalibrate both at mash temp (~150F) using my ThermaPen just to confirm... on my todo list!

Kal

 

[rollinred]

Well, I gone done it. Bobby's got ANOTHER order from me for the rest of the cam lock/barb fittings I need to set up this HERMS coil.

I really really really.... really, need to stop building equipment and start brewing. I've been a "homebrewer" for 5 years or so now and I've maybe made a dozen batches . Yet, I've managed to spend more on equipment than I even care to think about. How many batches could have been made if I could just be satisfied with what I have. This is it. I have to cut my self off after all this is done. Time to spend a few years brewing instead of building.

 

[kal]

As Bobby said there will always be some loss - it's inevitable. The PIDs only show 1 degree F increments so I could be losing 0.9F or less so it doesn't show up. It could be too that the RTD probes are not 100% linear in their response. I should go and recalibrate both at mash temp (~150F) using my ThermaPen just to confirm... on my todo list!

Just to close the loop: I did end up recalibrating both my MLT and HLT temp probes using my ThermaPen that was placed inline with the temp probes and the both agreed. So I can now confirm that at the important mash temp range (~145-158) whatever I set my HLT to my MLT follows within a degree or less as both PIDs show the same reading.

I know some people have offsets and I'm not sure why. In my case I think it's because:

- I flow with pumps 100% open using the center inlet March pumps which have good flow rate.
- I use hoses that have a thicker wall (1/2" ID, 7/8" OD).
- I brew indoors at ~62-72F where there's no wind which results in less heat loss.
- Probably some others reason I can't think of!

Kal

 

[augiedoggy]

Well, I gone done it. Bobby's got ANOTHER order from me for the rest of the cam lock/barb fittings I need to set up this HERMS coil.

I really really really.... really, need to stop building equipment and start brewing. I've been a "homebrewer" for 5 years or so now and I've maybe made a dozen batches . Yet, I've managed to spend more on equipment than I even care to think about. How many batches could have been made if I could just be satisfied with what I have. This is it. I have to cut my self off after all this is done. Time to spend a few years brewing instead of building.

wow I dont feel so bad now....I also have spent more on equipment than beer ingredients.

 

[BadNewsBrewery]

Kal - flowing your mash at 100%, do you find you get any stuck mashes, or do you stir frequently / mash with a higher water ratio to help?

 

[heckels]

Kal - flowing your mash at 100%, do you find you get any stuck mashes, or do you stir frequently / mash with a higher water ratio to help?

I was wondering the same. I typically have mine at about 50% for fear of a stuck mash.


Sent from my iPhone using Home Brew

 

[heckels]

I know some people have offsets and I'm not sure why. In my case I think it's because:



- I flow with pumps 100% open using the center inlet March pumps which have good flow rate.

- I use hoses that have a thicker wall (1/2" ID, 7/8" OD).

- I brew indoors at ~62-72F where there's no wind which results in less heat loss.

- Probably some others reason I can't think of!



Kal

My mash tun is also not insulated. I like the stainless bling too much to cover it up.


Sent from my iPhone using Home Brew

 

[kal]

Kal - flowing your mash at 100%, do you find you get any stuck mashes, or do you stir frequently / mash with a higher water ratio to help?

No stuck mashes, even with 60% sticky wheat and no rice hulls. I usually do the average 1.25 qt/lb mash thickness for most beers. Beers I want dryer like light lagers or something like Pliny the Younger (3x IPA) I'll do thinner, 1.5 or even 1.75.

Never stir your mash in any recirc system (HERMS/RIMS). You'll destroy the filter bed.

One of the big tricks is that with recirc setups you need to crush looser. You'll get higher efficiency too. Resist the impulse to pulverize the grain to dust. 0.045" gap or looser.

Kal