HERMS Temp Probe Location

[jeffmeh]

You wouldn't happen to have a link to that thread, would you? I'd like to read it.

Here you go. https://www.homebrewtalk.com/f170/does-turning-off-contactor-cause-pid-adjust-itself-381919/

 

[BadNewsBrewery]

What I've found through some testing is that if I heat my HLT about 10* over my target temp for the mash tun, and then dial it back down to the target temp when the mash tun is 8* below target, they'll equal out. Esentially, in the time it takes the MT to heat up 8*, the HLT has cooled 10*, and I hit my target. This also limits the offset I need between what I set the HLT at and what the actual target for the MT is, as the HLT is no longer trying to heat the wort, simply maintain temperatures. In real numbers:

Mash target: 152
Set Value for HLT: 162
Mash starts to heat up. When Mash temp = 144, HLT set to 152 (which basically turns off the element as I'm 10* over).
Mash continues to rise, HLT starts to cool, and everything balances out right around 152*. Element in HLT fires to maintain 152* HLT temp, mash continues to recirc at 152, everyone is happy.

Note - these values were determined by trial-and-error, and the sample size isn't large enough to say that it definitely works, but it's a good target for MY system. Yours will be different.

-Kevin

 

[kal]

FWIW I do it the "simple" way: I just set my HLT to the temp I want to the mash to be at and it follows automatically:

In the picture above the mash temp is the middle PID and the HLT temp is the right PID. Both are at 150F (mash temp).

After mash, the HLT temperature is raised from 150F to 168F to perform a mashout. The mash will automatically rise in temperature:

In the picture above the mash temp is at 162F and the HLT temp is at 168F. This picture is 15 minutes into this mash-out, the HLT has already reached and is holding at 168F, and the mash has gone from 150F to 162F. After anothre 5 mins or so it hits 168F as well.

(Pictures taken from my Step by step of my brewday: Doing a massive hop stand thread).

I have more pictures and videos of the entire process in my Brew Day Step by Step article that show how the mash follows the HLT through the various steps if you're curious.

Kal

 

[jeffmeh]

FWIW I do it the "simple" way: I just set my HLT to the temp I want to the mash to be at and it follows automatically:

In the picture above the mash temp is the middle PID and the HLT temp is the right PID. Both are at 150F (mash temp).

After mash, the HLT temperature is raised from 150F to 168F to perform a mashout. The mash will automatically rise in temperature:

In the picture above the mash temp is at 162F and the HLT temp is at 168F. This picture is 15 minutes into this mash-out, the HLT has already reached and is holding at 168F, and the mash has gone from 150F to 162F. After anothre 5 mins or so it hits 168F as well.

(Pictures taken from my Step by step of my brewday: Doing a massive hop stand thread).

I have more pictures and videos of the entire process in my Brew Day Step by Step article that show how the mash follows the HLT through the various steps if you're curious.

Kal

Another example that like many other things in life, in brewing, patience is a virtue.

 

[JayMac]

OK, delta between HLT and MT, not HLT and HEX out. I don't know why I was thinking delta between HLT and HEX out. That makes sense.

In your example, how much longer will it take to heat the wort if you set the HLT temp to 152 (plus a few degrees for loss from hex out to MT)? Does it add that much more time? I realize that it depends on a lot of variables, but are we talking minutes here or an hour?

I couldn't give you an exact time frame, as there are so many variables (HEX material, length, thickness, batch size, etc...)

This is something that you can only find out by tuning your system and figuring it out yourself once you've assembled everything. You want to see how big a deltaT you can get while simultaneously avoiding overshoot when you approach SP. trial and error my friend!

We can discuss theory all day, but the fact of the matter is that you'll determine your process based on your brewing style, preferences, time constraints, etc...

 

[theknub]

i started a thread about this, but i found my MLT was about 15 minutes behind my HLT. i could improve it like what bad news does, but i'm only on brew two of about one thousand.