Herms coil in hlt: pid-sensor placement

[Smellyglove]

I've just moved my herms coil to the hlt.

I must be overlooking something..

The heating elements in the hlt are triggered by the sensor sitting on the exit of the coil. But when I'm about to spathe this sensor will not track the spathe water.

How do I maintain temp for sparge water during sparging?

Right now I moved the sensor which I have in the hlt to the herms pid so the hlt sensor controls the elements. But there must be a better way?

 

[The Pol]

A lot of folks control the HERMS, by simply having one sensor in the HLT. Control that temp, and you will control the wort temp. Because, aren't they basically the same? That is what I've always done.

Individual results may vary

 

[flugelizor]

A lot of folks control the HERMS, by simply having one sensor in the HLT. Control that temp, and you will control the wort temp. Because, aren't they basically the same? That is what I've always done.

Individual results may vary

This...
I have one temp probe in the HLT then you can control the HLT temp any time, even when there is nothing in the coil.

 

[Smellyglove]

Doh! My mind was stuck on doing the same as before.

 

[doublehaul]

do you pump the entire mash then? I was watching a video on High Gravity brewing and they seem to have a pid for the HLT for maintaining temp, and one on the MT that would kick on the pump when the temp drops. seemed like a good idea to not run the pump the whole mash

http://www.highgravitybrew.com/store/pc/EBC-III-with-Infinite-Power-Control-p3858.htm

 

[Bobby_M]

Cycling a pump to control mash temps is an alternative philosophy on HERMS brewing and I think it's an older idea. The known problem with this is stratification in the mash tun can cause the pump cycling to be erratic. It's only measuring one small pocket of mash temp.

 

[stevehaun]

I put my thermowell at the output of the HERMS coil. I don't care what the HLT water temp is. I control the temp of the wort returning to the mash tun.

 

[kevink]

I put my thermowell at the output of the HERMS coil. I don't care what the HLT water temp is. I control the temp of the wort returning to the mash tun.

This guy gets it!

 

[Smellyglove]

I put my thermowell at the output of the HERMS coil. I don't care what the HLT water temp is. I control the temp of the wort returning to the mash tun.

So you don't do anything about the sparge temp?

 

[Smellyglove]

I put my thermowell at the output of the HERMS coil. I don't care what the HLT water temp is. I control the temp of the wort returning to the mash tun.

So you don't do anything about the sparge temp?

 

[flugelizor]

I think he probably sends his sparge water through the coil, so it is controlled the same way. This also cleans the coil.

 

[The Pol]

Since the sparge water is the control mechanism for the HERMS, you could do this. Pump the sparge water through the HERMS as you heat it to sparge temp, returning it to the HLT, then when you reach the proper temp, sparge. Depending on your setup, you may need to turn off the heating elements during the sparge, correct? So correcting the sparge water temp WHILE sparging may not be an option.

With the sensor in the HLT, you could set your HLT temp to 170F during the last minutes of the mash. This would begin raising the grain bed temperature, and heat your sparge water simultaneously, to your desired temp. Pull your MLT outlet hose, place it in the BK, place the HLT outlet hose on the HERMS inlet, and begin to sparge. You aren't using the HERMS to correct temp at this point, but you are cleanin the HERMS coil.

If you test both locations, you will see that the results are the same. There is no difference between locating a temp sensor in the HLT or in the HERMS return. The only difference is that you can also observe and control the sparge water temp in the HLT, if the sensor is actually in the HLT.

The goal is to take a flow of wort, and by the time it exits the HLT HERMS HEX, it has been corrected to the HLT water temp. So, where you mount the sensor is inconsequential. However, if you deem it important to be able to directly monitor and control the HLT temp, to control your sparge water temp directly, you'd be better off controlling the HLT temp.

Both methods will give you precise mash temp control.

 

[Smellyglove]

Sending sparge water through the coil.. what a great idea! Cleaning the coil, flushing out leftover wort and also use the same sensor to control sparge water temperature. Thanks guys!

 

[The Pol]

Just be sure as you draw down your sparge water, your element stays submerged. If you keep it on.

 

[Smellyglove]

Just be sure as you draw down your sparge water, your element stays submerged. If you keep it on.

Yeah I have the outlet on the HLT above the elements.

 

[stevehaun]

As a matter of fact, I do pump my sparge water thru my HERMS coil to clean it. I don't do it for temp control. My sparge water is several degrees warmer than my mash - I don't bother raising it to 165-170F. Nothing wrong with doing that, I just don't bother. I don't mash out either anymore either.

 

[Smellyglove]

Just to somewhat derail my own thread..

When it comes to temp-rises.

I'm looking at the same amount of W's pr liter as I had before I moved the coil from an external herms to internal in the HLT. Yet my initial tests with plain water are telling me that the temp-rises are slower now with the coil in the hlt.

Before: 3000W, 10liter herms container + 20 liter mash = 100W pr liter

Current: 4000W, 20 liter HLT + 20 liter mash = 100W pr liter

Can someone explain why (if) temp rises will take longer when it's the same W/liquid ratio?

 

[The Pol]

I'm guessing this.

The HLT volume is your heater, really, not your element. You doubled the mass you have to heat, In order to raise the mash temp.

You just nearly doubled the time it will take to raise the HLT one degree, the HLT has to heat up in order to heat the HERMS coil. You just doubled the volume, increasing the time to heat the HERMS.

The smaller the HERMS water volume, the more efficient the heating of the wort/mash.

You'd think watts to mass would be the same, and make no difference, but your experiment just taught us all a lesson.

What was the time difference??

 

[The Pol]

According to my calculations...

Your initial setup would raise the HEX water temp 100F in 13 minutes.

Your new setup will heat the HEX water temp 100F in 20 minutes.

Your new setup heats 54% slower than your previous design.

 

[Smellyglove]

I didn't time it.. I always forget that I'm timing it so I forget to stop the clock...

Would a way smaller (6ft) coil in a 2 L 2kW heater be faster?

I don't get how coil length affects this.

I'm glad this herms-in-hlt was just an experiment. HLT temperature is about 4C over herms-exit temperature when heating, and 3C when Set temp has been reached. Strange. 50ft SS coil inside.

 

[The Pol]

Coil length doesn't affect it. Coil material could to a degree, but with 50', there should be enough coil to saturate the wort with heat prior to exit. Copper is a better conductor of heat than stainless.

I think the volume you are heating in your HLT does play a role. You dramatically slowed your HLT reaction time when you increased its volume by 100%, and increased wattage by 33%.

Did you switch coil materials? You mentioned stainless, was the old coil copper?

Without real data, I'm not sure why it takes longer. I can only assume. The only fact that I do know is that your HLT heats slower, and reacts slower to heating commands, because your watts/l in the HLT is much lower than your original setup.

Remember, the water in the HLT is diluting the BTUs that the element is producing, before it reaches the coil, which carries the wort that you wish to heat.

You cannot change the temp of the wort in the coil, until you change the temp of the water surrounding it. By increasing the water volume surrounding it, you just ensured that it will take longer to heat the wort in the coil.

My .02

 

[Smellyglove]

The old one was copper yes, but way shorter and somewhat smaller ID.

Right now I'm looking at rise times of 0.5C per minute.

I'll rebuild the brewery later tuday after I'm done with todays brew and try the 1.8L herms-container with a 6mm (very small ID) copper coil, fired with a 3kW element. AFter swithing to blichmann FB I'm getting stuck mashes all over the place if I recirc to fast (even after strike, my mill is milling to fast, I get some powder), so I guess a 6mm ID still is within reason comparing to what my setup can cope with without getting stuck.

I'll sell two of the herms-setups i have laying around, just wanted to try them all before I decide on which one to keep. In the long run I guess I'll do a Herm-It coil from gryphon brewing in a 2kW electric jug.

 

[Smellyglove]

Coil length doesn't affect it.

My .02

I also responded to you without quoting in the post above..

People say that the longer coil the better. I don't understand why. In my mind there is no point in having a 50ft coil if the set temp is reached after 10ft. It's not like the wort gets "better warm" or anything, afaik.

 

[The Pol]

Were you recirculating the HLT water as you heated it? With an HLT of that volume, you should be mixing the water somehow.

 

[The Pol]

I also responded to you without quoting in the post above..

People say that the longer coil the better. I don't understand why. In my mind there is no point in having a 50ft coil if the set temp is reached after 10ft. It's not like the wort gets "better warm" or anything, afaik.

True, there is a point where the wort is saturated, so any additional length is unnecessary. You will get more efficient heating with a smaller diameter coil, and using copper.

 

[Smellyglove]

Were you recirculating the HLT water as you heated it? With an HLT of that volume, you should be mixing the water somehow.

Yes. I have a small pump inside the HLT. But still with that kind of volume I'm reading fluctuating temperatures some times since i have two elements at the bottom, when they fire up. I had a way more steady temperature in the 10L, also with an immersed pump. I guess the area in HLT is too big for just having one 10cm probe in it. Herms exit coil was also fluctuating whenever the elements fire up.

 

[Smellyglove]

Aight. With 1.8L 10m 6mmID tubing, 3kWI'm having way better ramp times than with the HLT. 6mm is maybe 2mm to little. I'm recircing at 3.5L/min with plain water. I guess this will drop a bit when dealing with wort.

Next step is getting a SS HLT and a coil from gryphon brewing. Then I'm done upgrading for a while.

 

[The Pol]

Boom. Glad you figured it out.

 

[Smellyglove]

It was somewhat expected. It's just easier to get full answers if you ask "why" questions

But I actually didn't think about that the HLT-volume was the medium. I first thought that everything need to be heated either way.