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jollyjake

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So, I feel I want better control of the mash temp. I am currently using the tried and true "Flame ON" method. Lots of experianced guys seem be move to HERMS so I would like to know:


With a HERMS do you continuously cycle the wort or just as needed to bring the temp back up?

Mash temp: do you take the reading at the outflow from the HERMS or within the mash bed?

(I am guessing that its continuous and that you control/measure the temp leaving the HERMS.)

I am thinking of converting my immersion chiller to be HERMS by dropping it in a small SS brew pot full of hot water and piping my wort through it.

I currently cont. recycle my wort with a pump now so I have the pumps and hoses. I just want to control temps better!

Cheers!
 
So, I feel I want better control of the mash temp. I am currently using the tried and true "Flame ON" method. Lots of experianced guys seem be move to HERMS so I would like to know:


With a HERMS do you continuously cycle the wort or just as needed to bring the temp back up?

Continuously cycle it during the mash

jollyjake said:
Mash temp: do you take the reading at the outflow from the HERMS or within the mash bed?
(I am guessing that its continuous and that you control/measure the temp leaving the HERMS.)

Both.. The output of the HERMS is important of course to know what temp your mash temp is headed in, but I also measure with a probe halfway into the mash to get a feel for when the mash as a whole has reached the temp I was going for

jollyjake said:
I am thinking of converting my immersion chiller to be HERMS by dropping it in a small SS brew pot full of hot water and piping my wort through it.

I currently cont. recycle my wort with a pump now so I have the pumps and hoses. I just want to control temps better!

Cheers!

That's basically what I did, took my old chiller and put it into my HLT keggle.
 
I only measure temp at the MLT output. I set my eHLT for the mash temp and circulate continuously. There is no chance of overheating this way. Of course auto control on the HLT is a must.
 
I built an eHERMS using a BCS-460 to control temps. I recirculate during the entire mash and measure the output at the heat exchanger (HEX). I also use and recommend a standalone HEX rather than a combination HEX and HLT. A standalone HEX allows you to adjust mash temps completely independent of your HLT. This means you can continuously recirculate and also do step mashes if you want.
 
I built an eHERMS using a BCS-460 to control temps. I recirculate during the entire mash and measure the output at the heat exchanger (HEX). I also use and recommend a standalone HEX rather than a combination HEX and HLT. A standalone HEX allows you to adjust mash temps completely independent of your HLT. This means you can continuously recirculate and also do step mashes if you want.
I like what user JoeHPhil did with an old corny keg. Seems pretty straight forward. No experience with electronics or controllers, so I am not sure ware to start reading about putting a controller together.

http://i818.photobucket.com/albums/zz101/JoeHPhil/BrewMachine1.jpg
 
I also use and recommend a standalone HEX rather than a combination HEX and HLT. A standalone HEX allows you to adjust mash temps completely independent of your HLT. This means you can continuously recirculate and also do step mashes if you want.

Each has it's merits.. I like the simplicity of using the heat in the HLT, but I readily admit that stepping takes about a degree a minute or so and could be much faster with a separate HEX. I don't do alot of stepping, especially nothing that needs to be fast. Usually just a sacc rest then move to mashout but I've done a rest at 140 and slow ramp to mashout over 2 hours for my golden strong which resulted in a very dry beer (as intended). Continuous recirc isn't limited to separate HEX though, I heat my entire (or most of it) volume in my HLT to strike temp - then mash in and add just a tiny bit of fresh water to my HLT to bring it down to mash temp - then recirc. It's takes longer for the mash temp to settle than it does for me to get my HLT to the correct temp.
I would caution that if you're planning to control the HLT temp using the output of the HEX you need to be 100% sure that you've got a good recirculation going with your pump before you walk away from it. I've had a few instances where things were pumping just fine, then I turned my back to do something and the pump slowed or stopped and my HLT temp ran away from me because there was no flow at the HEX so it wasn't raising in temp the way the HLT was. These days, I use the HLT temp to control the recirculation for that reason. There's a 3-4 degree differential between HLT temp and the temp at the output of the HEX (really at the input of the MLT where I measure) so I just figure that in when I set the temp.
 
Ideally you want to be measuring temp at the HEX out, as it is the hottest part of the closed system.

I use separate HEX, I prefer the modularity of that setup, I can skip it altogether or use it to chill. I can easily step mash. But both definitely have merit, whatever better suits your budget and needs is the right choice.

I like the ability to change mash temperature on the fly. I pause at dough in then recirculate continually, no reason not to with a separate HEX. I also use a BCS460, great gadget.
 
coogee said:
Ideally you want to be measuring temp at the HEX out, as it is the hottest part of the closed system.

I use separate HEX, I prefer the modularity of that setup, I can skip it altogether or use it to chill. I can easily step mash. But both definitely have merit, whatever better suits your budget and needs is the right choice.

I like the ability to change mash temperature on the fly. I pause at dough in then recirculate continually, no reason not to with a separate HEX. I also use a BCS460, great gadget.

If you only measure temp at the HEX out, how do you know the actual mash temp? When I ramp with my system, my HEX out is exactly my set temp (60 ft 3/8 copper coil).

The wort exiting the mash is the temp I'm interested in and the difference from top to bottom of the mash can be substantial.
 
Exactly why I measure both (I have a 12" probe stuck into the center of the mash), but I like the idea of measuring the MLT out - maybe I'll change things up in the future to that.
 
...the difference from top to bottom of the mash can be substantial.

If you're using a controller based system this is exactly why you want to measure the output of your HEX rather than the output of mash tun. If you're controlling off your mash tun out and you missed your strike water temp, it will have a tendency to overheat the HEX.

For example, let's say your target mash temp is 152F and you didn't hit your strike water temps and ended up at 142F. Your system is going to keep heating the mash until your temp at the bottom of your mash reaches 152. That means the liquid being returned to the top of your mash is greater than 152...lets say 162 for arguments sake. The 162 liquid continues to heat your mash past 152 until it reaches equilibrium. Long story short, if you try to control it this way you're introducing lag time into your system and you'll overshoot your mash temps.

On the other hand, if you measure at the HEX out, you'll never overshoot your mash temps because the liquid exiting the HEX will never exceed your set mash temp. My system generally heats at least one degree per minute. So in the same scenario above, if I was shooting for 152 but strike temp was 142, I'd get up to 152 in no more than 10 minutes. At that point the heating element shuts off and only intermittently turns on in order to maintain temps. So you get much tighter temp control measuring it this way. If you're measuring the temp at the mash tun out just for informational purposes rather than actually to control temps, there's no harm in it but I don't think it's necessary.
 
bruin_ale said:
Exactly why I measure both (I have a 12" probe stuck into the center of the mash), but I like the idea of measuring the MLT out - maybe I'll change things up in the future to that.

I like it. Here's how I set mine up:

ForumRunner_20120225_152510.jpg
 
microbusbrewery said:
If you're using a controller based system this is exactly why you want to measure the output of your HEX rather than the output of mash tun. If you're controlling off your mash tun out and you missed your strike water temp, it will have a tendency to overheat the HEX.

For example, let's say your target mash temp is 152F and you didn't hit your strike water temps and ended up at 142F. Your system is going to keep heating the mash until your temp at the bottom of your mash reaches 152. That means the liquid being returned to the top of your mash is greater than 152...lets say 162 for arguments sake. The 162 liquid continues to heat your mash past 152 until it reaches equilibrium. Long story short, if you try to control it this way you're introducing lag time into your system and you'll overshoot your mash temps.

On the other hand, if you measure at the HEX out, you'll never overshoot your mash temps because the liquid exiting the HEX will never exceed your set mash temp. My system generally heats at least one degree per minute. So in the same scenario above, if I was shooting for 152 but strike temp was 142, I'd get up to 152 in no more than 10 minutes. At that point the heating element shuts off and only intermittently turns on in order to maintain temps. So you get much tighter temp control measuring it this way. If you're measuring the temp at the mash tun out just for informational purposes rather than actually to control temps, there's no harm in it but I don't think it's necessary.

I see your point with the way you are controlling your system. My HEX water (HLT) is set to my mash temp so there is no way for me to overheat. When I ramp, I just bump up the HLT temp and continue to circulate until my MLT out is where I want it. Same as yours but different;)
 
I use two cheap e-bay aquarium temp controllers in my HERMS, one for the HLT burner, and a second that controls the pump. I have thermowells at the MLT in, MLT out, center of the HLT, center of the MLT, and even one in a separate pot. I usually measure the temp for the burner controller at the center of the HLT (I also have a stir motor to keep the water circulating). I measure the pump controller at the MLT in (HEX out). It mostly serves as a back-up device to shut the pump off if something goes wrong and the temps spike or drop unexpectedly. I usually stick a couple thermometers in the thermowells that aren't in use just to be able to verify that things are doing what they're supposed to be doing.

My HEX coil is mounted to a stock pot lid, so I can use it as an IC, or configure things any number of ways, including using the other pot to make the HEX separate from the HLT for faster step mashes. I rarely if ever configure it that way though, and usually have it mounted in the HLT.
 
lschiavo said:
If you only measure temp at the HEX out, how do you know the actual mash temp? When I ramp with my system, my HEX out is exactly my set temp (60 ft 3/8 copper coil).

The wort exiting the mash is the temp I'm interested in and the difference from top to bottom of the mash can be substantial.

Others have chimed in already but since it is the hottest point and since I am continually recirculating, the HEX out is where I hit and maintain my target temperature.

I do monitor my Mash temp and the two always equalize but you need to measure HEX out to control mash temp, if you do it the other way round you lose the exact control over temp HERMS provides.

The wort exiting the MLT will be the coolest point, soon to be heating in the HEX, I don't see the point in measuring this for control.
 
I see your point with the way you are controlling your system. My HEX water (HLT) is set to my mash temp so there is no way for me to overheat. When I ramp, I just bump up the HLT temp and continue to circulate until my MLT out is where I want it. Same as yours but different;)

Ahhh, that makes sense. Just out of curiosity, are you using electric or gas to heat your HLT/HEX? And how long does it take you to get from mash up to mash out temps (168-ish)? My eHERMS does a little over a degree per minute but I would thing a gas fired HERMS would be able to ramp up quicker (I guess subject to burner size).
 
microbusbrewery said:
Ahhh, that makes sense. Just out of curiosity, are you using electric or gas to heat your HLT/HEX? And how long does it take you to get from mash up to mash out temps (168-ish)? My eHERMS does a little over a degree per minute but I would thing a gas fired HERMS would be able to ramp up quicker (I guess subject to burner size).

My system is all electric. HLT is a sankey with a 4500W element. I am around a degree per minute on 10 gallon batches. Usually about 15 minutes will get me to mash out. I have everything but the time to add a second element in the HLT. Ramps should be much quicker then.
 
coogee said:
Others have chimed in already but since it is the hottest point and since I am continually recirculating, the HEX out is where I hit and maintain my target temperature.

I do monitor my Mash temp and the two always equalize but you need to measure HEX out to control mash temp, if you do it the other way round you lose the exact control over temp HERMS provides.

The wort exiting the MLT will be the coolest point, soon to be heating in the HEX, I don't see the point in measuring this for control.

I realize there are different control systems out there hence the need for monitoring temps at different locations in the system.

My HEX coil is always at mash temp so monitoring that is pointless with my system. I monitor MLT out so I know when the entire mash is at the target temp.
 
Hey guys, I'm building a HERMS system and I have a question:

If you are using a cooler for a mash tun, why continue to circulate after you have hit your mash temp and things have had a chance to equalize? Doesn't that happen pretty quickly? Why continue to run the pump and HEX?

My current system will maintain a temp with about a degree loss in the MLT cooler over an hour... getting it to the exact temp I want has been the problem thus far and that's why I'm building the HERMS system.

Also, what flow rate do you go for? As much volume as possible without getting a stuck mash/sparge?
 
disney7 said:
Hey guys, I'm building a HERMS system and I have a question:

If you are using a cooler for a mash tun, why continue to circulate after you have hit your mash temp and things have had a chance to equalize? Doesn't that happen pretty quickly? Why continue to run the pump and HEX?

My current system will maintain a temp with about a degree loss in the MLT cooler over an hour... getting it to the exact temp I want has been the problem thus far and that's why I'm building the HERMS system.

Also, what flow rate do you go for? As much volume as possible without getting a stuck mash/sparge?

I recirculate during the entire mash for a couple reasons. These include wort clarity, ensuring there is no stratification in the MT, and there are reports of better mash efficiency when recirculating compared to not (I think I heard it on Brew Strong but I could be wrong). Not saying you have to do it that way but it works for me.
 
P.S. I use a pretty low flow rate; 1/2" ball valves are typically between 1/4 and 1/3 of the way open. I've found this allows for good heat exchange in my HEX and prevents the grain bed from compacting.
 
Hey guys, I'm building a HERMS system and I have a question:

If you are using a cooler for a mash tun, why continue to circulate after you have hit your mash temp and things have had a chance to equalize? Doesn't that happen pretty quickly? Why continue to run the pump and HEX?

My current system will maintain a temp with about a degree loss in the MLT cooler over an hour... getting it to the exact temp I want has been the problem thus far and that's why I'm building the HERMS system.

Also, what flow rate do you go for? As much volume as possible without getting a stuck mash/sparge?

I actually don't start recirculating until ~10 min into the mash a lot of the time. Since I often heat my strike water in my HLT (always when doing double batches), the water in the HLT won't be at the proper temp for running the HERMS right away. IMO a HERMS is more for maintaining temps, or ramping temps up than it is for hitting your strike temp. If your main goal is hitting your strike temp accurately, building a HERMS isn't the best or easiest answer IMO.

If you take the time to input the mass and specific heat of your MLT, weight and temperature of grains, desired mash thickness and temp into any brewing program, the strike temp it gives you should get you really close to your desired mash temp. Brewtarget is totally free and does a pretty good job. After a couple batches you should be able too fine tune it to hit your mash temp dead on every time. Mashing in slightly thicker than your goal will leave room to add a little cold or boiling water to make slight adjustments. Even if you have your HLT water at the proper temp immediately after mashing in, it may take some time for the mash temp to equalize depending on how much adjustment is required. It's often much faster to mash in slightly thick and add a little hot or cold water.

As for reasons to recirculate throughout the mash, the main two were mentioned above: reduction of temperature stratification in the mash, and wort clarity. Most people keep the flow pretty slow. This helps prevent mash compaction and stuck mashes. It doesn't really need much flow to maintain uniform temps.
 
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