Dedicated Herms Guide, Problems And Solution Thread

[GrumpyPaul]

So I checked the STC probe and the thermometer in a cup of hot water and they both read almost spot on (+/- 0.1)

But when the STC is in the HEX it definitely reads 3degrees lower than the mash bed.

I did another brew and calibrated the STC accordingly. I checked it several times and mash temp and and hex temp were align perfectly.

I cant for the life of me think of a logical reason why the temp in the Mash bed could be 3 degrees higher than the HEX outlet if anything I would have thought it should be lower.

But recalibrating the STC when I use it in the HEX isn't an impossible workaround.

It does mean that my first couple of brews on this rig before I figured this out were probably mashed a little high at around 69-70degrees.

 

[jonnir]

How long were you letting it recirc for at your set temp before taking readings?

 

[woodfired]

I bought my PIDs from ebay with 1/2 inch threaded rtd100 thermocouples. Set me back a huge $25 so I bought two and set one up on the tun output and one on the tun input. I control the herms element with the input thermocouple and just have the output one showing up on the second PID as a reading. Figured 25 bucks was worth the extra info. It gives you a really good feel for if your flow is sufficient. Mash temp spot checks line up pretty well with output temps but controlling input is the way to go because if your flow is right they track pretty well.
Ps. I have stainless tee fittings with thermocouple in one end of the 'straight' and the input in the other with the output out of the third port. This sets the thermocouple pointing into the flow.

 

[Yob]

HEX MKII

5 LT Birko, still to be insulated same as the HLT but getting the hoses sorted out

 

[Hugh Jarse]

I need help please.......
I have just finished a rebuild on the rig and have gone the electric route (was gas fired). HERMS coil from Nev at Online Brewing Supplies and it worked a treat when I made the poly herms tube.
Since new electric rig completed, have included the HERMS in the HLT aka The Electric Brewery.
Cleaning and commissioning phase today, and while it takes me 1 hr to get 40l in the HLT to 65, for the life of me I can't get the HERMS and Mash up to 65...............
I have tried just about everything..... throttle valve at pump out, throttle valve at recirc to mash, heat HLT first and then recirc, heat both at once...... I am really scratching my head.
The only thing that has changed is the fact that I got rid of the Herms tube and single 2000w element and put it all into the HLT with control from the panel.
I have tested with multiple thermometers and all that is displayed is correct.
Esky is the same as before, pumps the same.
I am really scratching my head now..........

 

[mb-squared]

Kal runs the valves on his rig wide open to get the temps in the MT and HLT to be the same. but he has a 50' HERMS coil. it looks like you've got about 2'. not sure that's the reason, but it'd be where I'd start.

I have a similar setup to yours (in terms of HERMS in HLT, at least) and am able to get the temps in the MT and HLT be the same -- but I have 50' of copper coiled up in my HLT.

When you were using that coil in a poly tube, I'm guessing the temps in the poly tube were quite a bit higher than the temp you are running your HLT at in your new setup?

 

[Hugh Jarse]

Very good point there mb-squared, I hadn't thought of the temp probes measuring the different places and you are right with regards to the temp being hotter in the herms tube. Thanks for that, I will look at investing in some copper for a herms coil instead or run the HLT about 5 above the desired mash...... Cheers

 

[Hugh Jarse]

Just tried and 7 above seems about right. Thanks mb for that insight, helped heaps! Now just have to wait about 5 weeks before I can brew a SMaSH

 

[TheWiggman]

7°C difference?! That's a heap. Do you run both pumps at the same time right from firing up your element? I can imagine the MT will lag behind a bit but 7°C seems high.
I'll bet if you leave it for ages the difference will narrow as the rate of change in the MT will drop when you get closer to the 'target' temp. And as mb-squared said, keep those valves wide open. Also consider investing in some additional insulation.

By the way, that's one tidy looking setup you've got there.

 

[Hugh Jarse]

Thanks Wiggman, will have to invest in some insulation down the track and just ordered 2 x 4500w elements, currently running 3500w on a 20 amp dedicated brewing circuit. Will look at changing out the herms for copper depending on the price of it at the local hardware today. Alternatively could go with the 3/8 50' stainless chiller from grain and grape but not too sure on the 3/8" diameter and flow restriction? Anyone running. 3/8" coil?

 

[mb-squared]

if the "3/8" refers to the internal diameter, then that should be fine. if it refers to the OD, then it's probably too small. my coil has an OD of 12.7mm (1/2"), so its ID is probably right at 3/8" and it works well enough.

 

[TheWiggman]

3/8" will be OD.

Smaller dimameter tube will give you better heat transfer (more turbulence) for a given length but will restrict flow, which will reduce the transfer rate*. I'd stick with 1/2" for cost, more available fittings and higher flow rate, which will probably result in more efficient heat transfer.

* ED: for small poly pumps like yours

 

[Hugh Jarse]

Thanks Wiggman and mb-squared for your input. Have gone for the 1/2" copper and managed to cram about 14-15m into my pot utilising the deadspace. I realise the coils restricts flow but really didn't want the hex to be any higher in the pot and wanted to utilise the same holes from previous hex.
Tested today and works a treat. Hex out stayed about 2 degrees behind the HLT and the mash bed (20l) was about 2-3 degrees behind that. About 15mins after HLT was at temp the mash got there. Return flow is a little slow but will reconfigure the sparge arm to account for that.
Waiting on 4500w ripple elements and then will be in action.
Thanks for the help people.

 

[mb-squared]

wow, I'm really impressed with how neat and tidy that coil looks. geeze, I wish I could bend tube like that!

 

[Hugh Jarse]

Thanks mb, took a bit of effort and a few choice words but got there in the end. Only one small kink on bottom of front left coil that I put there when I was working on getting it away from the element. Managed the last turn to the connection using a tube bender, had to otherwise I would have wasted the afternoon by kinking the shit out it.

 

[dent]

That thing looks cool but it is total overkill. I bet just one of those coils would do the job.

 

[TheWiggman]

Recently I seem to be ok then suffer from stuck sparges. I use a braided hose as you can see below -

Last 2 brews took about 2-2.5h to sparge because the unassisted flow rate from the MLT was barely a trickle. Got brilliant efficiency, but it was slow and painful.

Yesterday I did AndrewQld's CPA clone and found that with the very fine crush the wheat flour seemed to turn into a glue. I allowed about 10 mins of no circulation to start with, but after about 30 mins of mashing (52°C step) the flow almost stopped.
I turned the pump off and dug the base of pot out as it had settled HARD. Took quite a bit of elbow grease to dig it up. There were large solid clumps coming up which separated into solution when stirred. I backed the flow off to 50% once the pump was back on.
About 20 mins later I did the same thing with the pump running. Some minor settling.
I tried it a third time and it was much better. When sparging, liquor flowed out much better and I had to choke it off to avoid too much flow into the boiler.

In future this is what I'll be doing -

• Heat to strike temp
• Turn off pump, add grain
• Wait 5 mins
• Turn on pump, slowly increasing flow to 50%
• After 20 mins, stir settled grain, 50% flow
• After 10-20 mins, stir again and confirm loose grains. Adjust flow as needed.

An alternative is rice hulls or coarser crush, but this recipe came delivered.

 

[mofox1]

Recently I seem to be ok then suffer from stuck sparges. I use a braided hose as you can see below -

Last 2 brews took about 2-2.5h to sparge because the unassisted flow rate from the MLT was barely a trickle. Got brilliant efficiency, but it was slow and painful.

Yesterday I did AndrewQld's CPA clone and found that with the very fine crush the wheat flour seemed to turn into a glue. I allowed about 10 mins of no circulation to start with, but after about 30 mins of mashing (52°C step) the flow almost stopped.
I turned the pump off and dug the base of pot out as it had settled HARD. Took quite a bit of elbow grease to dig it up. There were large solid clumps coming up which separated into solution when stirred. I backed the flow off to 50% once the pump was back on.
About 20 mins later I did the same thing with the pump running. Some minor settling.
I tried it a third time and it was much better. When sparging, liquor flowed out much better and I had to choke it off to avoid too much flow into the boiler.

In future this is what I'll be doing -

• Heat to strike temp
• Turn off pump, add grain
• Wait 5 mins
• Turn on pump, slowly increasing flow to 50%
• After 20 mins, stir settled grain, 50% flow
• After 10-20 mins, stir again and confirm loose grains. Adjust flow as needed.

An alternative is rice hulls or coarser crush, but this recipe came delivered.

I can attest to the use of rice hulls.. I did a 30% rye, 20% wheat, 50% barley a week or two ago and it worked great. Similar mash tun setup too:

I did a 70% wheat w/o the hulls and it was *slow*. I mean really, reallllly slow. After the first slow sparge I came across a great solution - Pump your sparge water back up through the braid, it'll push out the finer crap that blocking it and allow the bigger husks to settle back over it. Mostly benefical for batch sparging, but could help if done periodically for fly.

Obviously you still need to stir & then recirc/vorlauf otherwise you'll end up with pretty thin runnings, but it worked a treat.

 

[RustyT]

So I have finally gotten around to building my brew stand. I'm about halfway through the build now and I'm pretty happy with it so far. Just waiting for the stainless fittings and temp controller to come, so I can build the HLT and herms arrangement. Speaking of which I have a couple of options for the HLT. I can get my hand on a pretty beating up 50L keg (looks like it actually fell of a truck) or I can use my old aluminium boil pot, which is still in ok condition after a good scrub with some scotch brite pad. Not sure which way to go, don't want to ruin the good looking rig with a busted up HLT.

Can't wait to do my first Herms brew!

 

[drifting79]

Rusty you will need a nice step or platform to work at that height for extended periods looks nice and neat