Where best to place the PID thermostat?

[Galena]

I am about to finalise my 56 litre mash kettle after buying all the parts well over a year ago.
Anyway, I am wondering what thoughts are on the best place for the thermostat for the controller? I will be using a re-circulation pump so considering putting it in 'T' piece in the line either just after the valve or else just before the return?
Other option is of course in the pot itself, but then it's best position for keeping an even temperature whereas I was thinking if it's in the line and the return temperature is correct then it should in theory be keeping the mash correct?

 

[Rugby Fan.]

I am about to finalise my 56 litre mash kettle after buying all the parts well over a year ago.
Anyway, I am wondering what thoughts are on the best place for the thermostat for the controller? I will be using a re-circulation pump so considering putting it in 'T' piece in the line either just after the valve or else just before the return?
Other option is of course in the pot itself, but then it's best position for keeping an even temperature whereas I was thinking if it's in the line and the return temperature is correct then it should in theory be keeping the mash correct?

From what I gather the mash has very unevenly temp distribution. What you really have to do is find a place and take that as your average.

The return from the recirc will be a bit lower than where the heating element is.

Perhaps you could place one near the element and one at the recirc return and work from that data?

 

[Buffers brewery]

In a “T” piece to measure the circulating wort temperature is as good a place as any, to start. You are going to have a temperature gradient through your mash in a tun that size. However, with a bit of trial and error and measuring the mash temperature in different places during the mash, you should be able to establish a “set” temperature that delivers the mash temperature you want.

 

[Galena]

In a “T” piece to measure the circulating wort temperature is as good a place as any, to start. You are going to have a temperature gradient through your mash in a tun that size. However, with a bit of trial and error and measuring the mash temperature in different places during the mash, you should be able to establish a “set” temperature that delivers the mash temperature you want.

Cheers, I have installed a fixed thermometer in the kettle and usually dangle an accurate digital during the mash so there will be plenty of analysis going on.
Do you think it matters which end of the hose it goes?

 

[Buffers brewery]

At the end of the day, my understanding is that mashing is all about achieving a steady (thermal) state so I’d suggest position the probe somewhere convenient to start with and see how things go. You might do a “dry” run with just water, no grain, to see how your set up works. Yes, it will be different with grain, but might give you a bit of confidence in your setup just trying with water. Another important aspect I’m sure you’re aware of is the path the wort takes through the grain. My tun is a rectangular picnic box hence my sparge contraption to spray the returning wort over the whole surface. So you need to disperse the returning wort to run through as much grain as possible. I’m sure you’ve thought of that but said it for completeness.

 

[Galena]

Another important aspect I’m sure you’re aware of is the path the wort takes through the grain. My tun is a rectangular picnic box hence my sparge contraption to spray the returning wort over the whole surface. So you need to disperse the returning wort to run through as much grain as possible. I’m sure you’ve thought of that but said it for completeness.

Indeed, my wort is usually at 3:1 so not overly dry, I assume that makes a narrow path a little less likely than with a thicker mash, I do stir fairly regulary too. I have been trying with my current setup to get a satisfactory atomised spray nozzle but each one I have tried has been a bit lack lustre though I have seen examples of them producing a good spread if I can only source one.

 

[The-Engineer-That-Brews]

I've tried a Tee piece and it was OK, but more recently I got a GF 'Wort-o-meter' and it's tons better: responds faster and definitely well worth the ££

In my setup I measure the temp of both the recirculating wort and the grain bed, and the grain is usually 1-2ºC cooler; so offset as necessary to get the mash temp you're after

 

[The-Engineer-That-Brews]

Indeed, my wort is usually at 3:1 so not overly dry, I assume that makes a narrow path a little less likely than with a thicker mash, I do stir fairly regulary too. I have been trying with my current setup to get a satisfactory atomised spray nozzle but each one I have tried has been a bit lack lustre though I have seen examples of them producing a good spread if I can only source one.

Another option (thanks @Clint) is to put a sheet of foil over the grain and then poke a lot of 'oles through it with a skewer - that gives a pretty even flow

 

[Rugby Fan.]

This may be of interest, saucey enough though and not sure how importing from the EU would work.

http://www.mattmill.de/mattmill-ruehrwerke/

 

[Galena]

I've tried a Tee piece and it was OK, but more recently I got a GF 'Wort-o-meter' and it's tons better: responds faster and definitely well worth the ££

An interesting option, may be worth a punt, does the probe screw in or just be held in place and seal with that silicone tubing? I did watch a David Heath video review and I wasn't sure.

Another option (thanks @Clint) is to put a sheet of foil over the grain and then poke a lot of 'oles through it with a skewer - that gives a pretty even flow

I used to do that for sparging before I went for batch sparging, never considered it for mash re-circulation but it would probably work quite well if it doesnt sink.

This may be of interest, saucey enough though and not sure how importing from the EU would work.

Interesting bit of kit, looks expensive though.

 

[The-Engineer-That-Brews]

An interesting option, may be worth a punt, does the probe screw in or just be held in place and seal with that silicone tubing? I did watch a David Heath video review and I wasn't sure.

The temp probe just pushes into the thermowell - I put a bit of silicone heatsink goop in there which holds it in quite nicely but I also put a bit of heat shrink over it. Looks like I also put a zip-tie over the heat shrink (at the bottom):

I used to do that [foil] for sparging before I went for batch sparging, never considered it for mash re-circulation but it would probably work quite well if it doesnt sink.

I don't think it could sink below the level of the grain unless the holes were so big that the grain could get thru?

 

[Rugby Fan.]

Interesting bit of kit, looks expensive though.

Ya, €340 for the impeller version which while not cheap, is good value imo.

But that's any hobby, there are things that are good value but still a lot of money and probably overkill

 

[The-Engineer-That-Brews]

Incidentally the outer diameter of the wort-o-meter inlet and outlet tubes is 3/8" which means you can shove it straight into a JG fitting

 

[MashBag]

Cheers, I have installed a fixed thermometer in the kettle and usually dangle an accurate digital during the mash so there will be plenty of analysis going on.
Do you think it matters which end of the hose it goes?

Chinese proverb springs to mind "man with two watches never know time"

 

[The-Engineer-That-Brews]

Chinese proverb springs to mind "man with two watches never know time"

Man with probe in grain know true enzyme activity
Man with probe in recirculation loop know how to adjust temperature of grain

 

[Rugby Fan.]

Man with probe in grain know true enzyme activity
Man with probe in recirculation loop know how to adjust temperature of grain

Man who run in front of car gets tired

 

[RoomWithABrew]

Man who run in front of car gets tired

Or gets run over!!

 

[Rugby Fan.]

Or gets run over!!

 

[MashBag]

Man with probe in grain know true enzyme activity
Man with probe in recirculation loop know how to adjust temperature of grain

 

[The-Engineer-That-Brews]

Just for interest I've just mashed in and started recirculating for a 65º mash (using my diy HERMS).

If I only had the wortometer reading to go by then I'd be about half a degree out on what I thought the actual grain temp is.
And while half a degree C doesn't sound like much it makes a significant difference in the enzyme activity: