HERMS Mash Temp Problem

[mona]

Hello All,
I recently made a HERMS. I have used it twice and it has worked like a charm. Well I thought so until I had some of the beer that it created. It was very tanic and super dry. A classic problem of a low mash temp. The problem is that according to the reading from the probe on my control panel showed the correct temp. I am taking the reading where the wort comes back from the HERMS coil into the cooler mash tun. I did a test on my last run and put a thermometer in the middle of the mash and lo and behold it was a good 9 degrees cooler than the wort coming from the HERMS. What am I doing wrong?

 

[mredge73]

I don't know how you are loosing 9 degrees from the top to the bottom of an insulated mash tun.

My SS Keggle has a delta of 2-3 degrees from top (hotter) to bottom (cooler). I use the temp probe toward the bottom of the mash tun as my feedback temp for the HERMS coil.
This way the average temp of the mash from taking temperature from the top, middle, and bottom will consistently be a little higher than my set point. This is part of dialing in your system, it takes a few batches to get it perfect.

 

[d3track]

Have either of those been calibrated

 

[jekeane]

If those temps are correct and not a calibration issue that I would assume you are getting a fair amount of channeling along the sides of your grain bed and the center is not getting the benefit of recirculation.

 

[AkBrewer49]

Check your temps in a couple of different places, if possible with a couple of different thermometers. You may need to calculate you PID, if thats what you are running. i had one that was a couple degrees off..

 

[mona]

I don't know how you are loosing 9 degrees from the top to the bottom of an insulated mash tun.

My SS Keggle has a delta of 2-3 degrees from top (hotter) to bottom (cooler). I use the temp probe toward the bottom of the mash tun as my feedback temp for the HERMS coil.
This way the average temp of the mash from taking temperature from the top, middle, and bottom will consistently be a little higher than my set point. This is part of dialing in your system, it takes a few batches to get it perfect.

I will think about putting the probe in the middle of the mash to regulate the HERMS. Try it that way. I guess I need to dial it in with a much cheaper brew

 

[mona]

Have either of those been calibrated

they have both been calibrated.

 

[mona]

If those temps are correct and not a calibration issue that I would assume you are getting a fair amount of channeling along the sides of your grain bed and the center is not getting the benefit of recirculation.

Now this could be the very problem. I am using a SS tube kind of manifold. I may need to go to a CPVC type of manifold to distribute the wort better. I did notice after draining the MT that there were channels along the side of the cooler. Not sure how that would happen since the tube goes down the center of the cooler.

 

[Ozarks Mountain Brewery]

the HLT water isn't at all what you read its the temp of the mash tun and the best place to put your probe is the out valve, you have to adjust your hlt to compensate to keep the mash the correct temp, it doesn't matter what the difference is, thats what you do, now with that said each temp probe wire can show a different reading so your pid will need to be calibrated to a specific probe, wire and pid and never changed

 

[jekeane]

Also as Ozarks said, I have my pid in a T at the wort out from the mash tun giving me the temp of the liquid wonder the false bottom. My Analog probe for my kettle is just above the grain bed for most 6 gallon batches and it is even with my pid probe when at a static temperature. The analog is higher than my PID while ramping as the hotter liquid is working to raise the grain bed temp.

 

[mona]

the HLT water isn't at all what you read its the temp of the mash tun and the best place to put your probe is the out valve, you have to adjust your hlt to compensate to keep the mash the correct temp, it doesn't matter what the difference is, thats what you do, now with that said each temp probe wire can show a different reading so your pid will need to be calibrated to a specific probe, wire and pid and never changed

the PID temp probe is taking the reading of the wort as it comes into the MT from the HERMS. The HLT is being controlled by the PID, which is calibrated, 32 in ice water and 212 in boiling. so sounds like we are in line there except for that you suggest that I put the PID temp probe as it comes out of the MT back to the HERMS?

 

[mona]

Also as Ozarks said, I have my pid in a T at the wort out from the mash tun giving me the temp of the liquid wonder the false bottom. My Analog probe for my kettle is just above the grain bed for most 6 gallon batches and it is even with my pid probe when at a static temperature. The analog is higher than my PID while ramping as the hotter liquid is working to raise the grain bed temp.

So do you then start your timer for the mash time, say 60 min, after both of the temp readings are the same?

 

[beernutz]

Hello All,
I recently made a HERMS. I have used it twice and it has worked like a charm. Well I thought so until I had some of the beer that it created. It was very tanic and super dry. A classic problem of a low mash temp. The problem is that according to the reading from the probe on my control panel showed the correct temp. I am taking the reading where the wort comes back from the HERMS coil into the cooler mash tun. I did a test on my last run and put a thermometer in the middle of the mash and lo and behold it was a good 9 degrees cooler than the wort coming from the HERMS. What am I doing wrong?

What capacity pump are you using and what diameter tubing does the wort flow through before, during, and after, it is in the HERMS coil? Are you setting the HERMS output temp at exactly the mash temp? How do you control the water temp surrounding your HERMS coil?

 

[jmark]

Hold on... you shouldn't put the probe anywhere but the output of the HLT or, the same thing, the input back to the MT. Putting it on the output of the MT will result in overheating the HLT water (which will be very difficult to cool back down when it inevitably becomes necessary) and having hotter than expected wort coming back into the mash.

If you're getting the efficiency you expect, then maybe just adjust your mash temperature. As you gain more experience with your system you'll be able to figure out what temperature gives you the desired results.

 

[Ozarks Mountain Brewery]

Hold on... you shouldn't put the probe anywhere but the output of the HLT or, the same thing, the input back to the MT. Putting it on the output of the MT will result in overheating the HLT water (which will be very difficult to cool back down when it inevitably becomes necessary) and having hotter than expected wort coming back into the mash.

If you're getting the efficiency you expect, then maybe just adjust your mash temperature. As you gain more experience with your system you'll be able to figure out what temperature gives you the desired results.

I have mine set up like Kals in this picture, you can go threw his step by step and get some info, note where the probs are

http://www.theelectricbrewery.com/brew-day-step-by-step?page=3

 

[jmark]

My setup is the same as Kals too and I probably should have clarified this with the following. While he has a probe on the MLT output, it's NOT used for control; it's only used for information. In fact Kal doesn't even bother with a probe on the output of his HLT (input to MLT) as his HERMS coil spits out wort at exactly the temperature of his HLT water (so adding the additional probe would be meaningless). Kal controls his mash temperature by adjusting his HLT temperature as I probably should have made more clear in my reply above.

I will reiterate my original point though... Controlling the mash temp by using the probe on the output of the MLT is asking for temperature overshoots and uncontrollable HLT temps (as you can't easily cool that water once it's overshot).

 

[Ozarks Mountain Brewery]

correct, i use mine the same and only use the MLT pid as a reading but it does come in handy if your low or high, you can adjust and quickly even them out, I went through the same thing as the OP was stating before I figured out about my wiring causing messed up readings, you can change a wire as your setting your pid and it will read differently than the next so just pick the one that has less resistance and mark it to always be used in that spot the change the pids both to match keeping the HLT as the heat source and the true 32,boiling setting, you cant really rely on 212 since water boils here at 109, but you figure it out

 

[augiedoggy]

the PID temp probe is taking the reading of the wort as it comes into the MT from the HERMS. The HLT is being controlled by the PID, which is calibrated, 32 in ice water and 212 in boiling. so sounds like we are in line there except for that you suggest that I put the PID temp probe as it comes out of the MT back to the HERMS?

Yes that way your actually measuring and controlling the temp of the mash and not the wort going in.

 

[augiedoggy]

My setup is the same as Kals too and I probably should have clarified this with the following. While he has a probe on the MLT output, it's NOT used for control; it's only used for information. In fact Kal doesn't even bother with a probe on the output of his HLT (input to MLT) as his HERMS coil spits out wort at exactly the temperature of his HLT water (so adding the additional probe would be meaningless). Kal controls his mash temperature by adjusting his HLT temperature as I probably should have made more clear in my reply above.

I will reiterate my original point though... Controlling the mash temp by using the probe on the output of the MLT is asking for temperature overshoots and uncontrollable HLT temps (as you can't easily cool that water once it's overshot).

except he has to adjust for the 2 to 3 degree loss that the wort looses traveling through the hoses in a room temp room and the loss from the mash tun wall cooling... this is why measuring and controling the actual mash tun temps is preferred by many despite what Kal does. as long as your pid is calibrated correctly and your flow is consistent you wont get these overshoots... you will however have temps that will fluctuate unless you are constantly stirring your HLT water.. otherwise the water near the element may be one temp, the probe may read another and the water around the herms coil may yet read a different temp.
this is the issue I had and one of the reasons I switched to a rims.

 

[jmark]

I don't lose any temperature though from the exit of the HLT... The hose is all of 6 inches back into the MT and while I may lose a degree or so BEFORE getting to the HERMS coil, by the time it gets out, it's identical to the HLT temp, so it's really easy to keep the mash at temp this way.

While I'm recirculating the mash, I'm also recirculating the HLT water too with the water pump. This way the HLT has a consistent temperature throughout.

The probe at the output of the MT confirms that the temperature is holding once met.

 

[jcav]

I also do it the same way as Kal and as the others here have posted and it really works. It is a very accurate way to measure it once it gets to the set temp. A good false bottom with no channeling is a must as well. Oh and yes you have to recirculate your HLT water like Kal does.

John

 

[stevehaun]

This has been debated ad nauseum on this site and others. I have settled on positioning the thermocouple that controls the HLT heating element right before the wort returns to the top of the mash tun. I also measure the temp of the wort as it exits the bottom of the mash tun. I do not recirculate the water in my HLT. I do have a dial thermometer in the HLT but I rarely look at it. So I am controlling the temp of the wort as it returns to the mash tun and measuring the temp of the wort as it leaves the mash. I usually stick a floating thermometer in the mash tun for confirmation. Once you dial in your system, you will learn how to set the PID temp to get the desired mash temp. I usually set my PID 4F greater than my desired mash temp. Some folks control the HLT temp and then extrapolate to the desired mash temp. With this approach it is important to recirculate the water in the HLT. Downside is you now need two pumps. Both approaches work. You need to learn your system and closely measure your mash temps.

 

[jekeane]

So do you then start your timer for the mash time, say 60 min, after both of the temp readings are the same?

I have only been running my system since the summer and have about a dozen batches on it. I follow Kal's setup and brew day guide which means I am doing 90 minute mashes. My mash in process looks like this:

Heat HLT water to 164°ish (varies on desired mash temp)

Pump Strike plus .5 gallon into Mash tun.

Recirculate strike water through HERMS to heat pumps etc and get back to strike I start by running off .5 gallon into a bucket to make sure HERMS coil didn't have anything left behind.

Dough in. I am generally a couple degrees under at this point and usually start my 90 minute timer now.

In my set up I generally need to add some cold water to bring my HLT back down to mash temps for recirculation.

I don't know much about all the discussion on problem placements and what you actually go by for your reading. But what I do now seems to work well. My probes are set up just like Kal's "The Electric Brewery" I also have my analog kettle thermometer that sits above the mash in the wort.

I set my HLT pid to 2° above my desired temperature which keeps my Wort Out PID and my analog steady at my desired temperatures. When I ramp up to my mashout I set my HLT for 175° I watch my top analog thermometer and when it is at 165° my bottom is usually 158°ish. At that point I drop my HLT back dow to 168° and pour in enough cold water to get down below 170°. I could just set the HLT at 168 from the start and walk away but it would take 10-15 minutes longer on my system.

Long post... In the end there are likely a few ways to accomplish what you want to do. To go back to your OP I think making sure your mash tun manifold isn't channeling is pretty important in figuring this out too.

 

[SilverZero]

The HLT is being controlled by the PID, which is calibrated, 32 in ice water and 212 in boiling.

What's your elevation? Here in Central Oregon my water normally boils at 205-206F (3500 ft).

You might also get around any potential channeling issues by using a thinner mash. Definitely at least 1.5 qts/lb if not more water, maybe even shoot for a no-sparge volume if you aren't already.

 

[mona]

Thank you everybody for all of your input.
My PID controls the HLT which has the HERMS coil in it.
the temp probe for the PID is inside the MT in a T. It is therefore measuring and controlling the HLT from the temp before re-circulation.
So it seems I need to work on a few things.
1. make a better manifold to eliminate channeling
2. measure the temp as it comes out of MT so that I can fine tune the temp of the entire mas
3. practice using the system and dial it in.
Thank you everybody. Great advice from a great group of home brewers.

 

[mona]

What's your elevation? Here in Central Oregon my water normally boils at 205-206F (3500 ft).

You might also get around any potential channeling issues by using a thinner mash. Definitely at least 1.5 qts/lb if not more water, maybe even shoot for a no-sparge volume if you aren't already.

I am in the valley. You are very much higher in elevation than I am. I think it is like 100 feet above sea level if that.
I do run at 1.5 qts/lb. the thing with my manifold the way it is now is that I have no idea if the thing is even at the bottom of the cooler.
So a change is coming for sure on that.

 

[jmark]

If you have any way to recirculate the HLT water, I would put your probe on the HLT output so you don't ever run the HLT hotter than your mash. If you can't recirculate the HLT you may run into stratification issues, so measuring the output of the HLT is probably your next best bet as you've indicated.

 

[beernutz]

Thank you everybody for all of your input.
My PID controls the HLT which has the HERMS coil in it.
the temp probe for the PID is inside the MT in a T. It is therefore measuring and controlling the HLT from the temp before re-circulation.
So it seems I need to work on a few things.
1. make a better manifold to eliminate channeling
2. measure the temp as it comes out of MT so that I can fine tune the temp of the entire mas
3. practice using the system and dial it in.
Thank you everybody. Great advice from a great group of home brewers.

The others issues may be part of the problem you are experiencing but IMO measuring the temp as the wort returns to the mash tun will help quite a bit.