Herms build advice

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sladeywadey
Hollow Legs
Posts: 377
Joined: Thu Dec 03, 2009 5:56 pm

Re: Herms build advice

Post by sladeywadey » Sun Sep 28, 2014 7:38 pm

Lockwood16 wrote:Sladeywadey, did you use 10mm copper tubing for your heat exchanger?

Yes I did. Works a treat but again you just need to flush through afterwards with water/oxyclean etc, rinse out and drain as much as you can.
I have purchased a 4.5L stainless steel pot ready for the fitting of a 2.4Kw heater. Undecided whether to fit coils coming from the pot lid, or fit these from the side.

I decided against fitting the 2.4Kw element on the bottom of the pot, instead I will fit this on the side, as low as it will fit, so the pot will be stand alone.
My 2.4kw element is on the bottom. I just stand my pot on an upturned bucket with a hole in the bottom.

I have purchased a low cost PID controller complete with PT100. I was wondering what fittings you used to fit the PT100 into the "T" piece. The PT100 supplied is 5mm, so I guess I need a 5mm to 1/2" reducer, failing that, 5mm to 1/4", then 1/4" to 1/2".
My probe is an 1/4" npt size (Auberins). This is fixed into a 'bush' which then is put into a radiator type T fitting. I can't remember the size of the bush and I got it from a local plumbers merchant.

Lockwood16

Re: Herms build advice

Post by Lockwood16 » Tue Nov 25, 2014 1:11 pm

I have completed my HERMS panel and set up, and it appears to work OK. I have fitted two PT100's, one on the "T" on the exit of the HERMS coil, the other on the "T" on the exit of the coolbox mashtun. Now I have only run this with water (and not at the full mash temperatures yet, as I am just testing the system), and would probably expect different results when the mashtun has actual grain inside, but obviously there is a small difference in the temperature between the exit of the HERMS coil and the exit of the mashtun. The PID is controlling the HERMS temperature via a kettle element in the 5L vessel, the other PID is for display only. (I know this is probably overkill, but I wanted to know what the drop in temperature would be, albeit small pipe runs etc)

Now if this is repeated on brewday, which mash temperature do you go with? The temperature of the mash returning to the coolbox from the HERMS?, or the temperature at the outlet of the coolbox?

Another thing I was wondering, is whether it is prudent to increase the water/grain ratio from 2.5L/Kg to say 3L/Kg, to reduce potential problems with stuck mashes.

Any feedback from your experience would be very welcome indeed, prior to my first brew with the new kit!

Best regards,

Lockwood16

Lockwood16

Re: Herms build advice

Post by Lockwood16 » Fri Nov 28, 2014 10:59 am

Update on temperature differential.

Ran the system at mash temperatures and the difference was minimal, less than 0.2 degrees so very happy with that.

Any update on recommended water/grain ratio? I am thinking upping it to 3L/Kg, has anybody found this a problem with stuck mashes?

Best regards,
Lockwood16

sladeywadey
Hollow Legs
Posts: 377
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Re: Herms build advice

Post by sladeywadey » Fri Nov 28, 2014 7:31 pm

I'd start with 3L and see how you get on. I would watch the pump speed and throttle it back on the pump outlet rather than full bore.

Lockwood16

Re: Herms build advice

Post by Lockwood16 » Sat Nov 29, 2014 10:10 am

Thanks for your reply, Sladeywadyey. I will take onboard your advice. My next brew will be in the new year as the fridge is currently occupied conditioning a lager for the son in law for Christmas!

Best regards,
Lockwood16

Lockwood16

Re: Herms build advice

Post by Lockwood16 » Sun Jan 04, 2015 11:39 am

Update on HERMS system.

Had a very trying day yesterday with the HERMS system in action for the first time.

After doughing in with a thinner than normal mash ie 3L/Kg (small 15L test batch). I had a stuck mash straight away despite leaving to settle for a few minutes, and continued to have poor circulation all day even when cleaning system!!

Just a recap on my system.
5L S/S vessel with 10mm copper coil with Kettle element inside, PT100's on exit of mashtun and exit of 5L HERMS vessel. PID controlling kettle element in 5L HERMS and the other PID for monitoring temp of 5L HERMS.

liquid flow is a follows:
Exit of valve of mashtun to bottom of mag pump, out of valve on exit of mag pump to input of HERMS, out of HERMS to top of mashtun.

Problems;
1 Stuck mash straight away. (Pump is a standard 12v magnetic pump from Angel homebrew)
Pump stripped down and grain removed. I should add that I have a homemade S/S false bottom on my Colemans coolbox, but grain does get through where the exit to the mashtun valve is.

This resulted in a mammoth mash time. When cleaning the system I still had poor circulation even running water through. It appeared that the pump could not cope with pushing the air through the HERMS coil even.

Any ideas on how to improve this ?

Best regards,
Lockwood16

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fego
Lost in an Alcoholic Haze
Posts: 524
Joined: Fri May 29, 2009 11:02 pm
Location: Charlestown, Cornwall

Re: Herms build advices

Post by fego » Wed Jan 07, 2015 12:16 am

I'm not sure you should expect much glory from such a small mash size but I wouldn't know for sure so here's some thoughts based on my experiences.

Did you manually recirc a few litres from the tun before using the HERMS? Unless it is running clear (ish), the solar pump is likely to block up and cause problems.

Also, are you able to regulate the speed of the solar pump? You may find you are pumping too quickly and sucking the bed dry before the wort is returned through the grain.

Another thought, how high is the false bottom in relation to the exit valve? If it is very close, you may only have say one litre of wort in the sump to play with which will obviously dry up very quickly. You might want to try raising the FB a bit if you can.

And finally, are you sure you have the fittings plumbed and wired properly for the solar pump I.e. In to the in and out to the out... red to red etc. It could just be fighting against gravity or running backwards/badly. Also, are you sure all of your fixings are air tight? You might have an air leak somewhere which won't be helping.

In terms of expectation, I use my solar pump at a very slow speed (poss 10% of max) and it has no problem pushing wort or water through a long coil and six foot above itself. My coil is 3/8ths beer pipe which I presume has the same dimensions as your 10mm copper, but if it is a very long length, perhaps all your wort is in the pipe explaining your stuck mash.

Hope you get it sorted...
Tea is for mugs...

Lockwood16

Re: Herms build advice

Post by Lockwood16 » Sun Jan 11, 2015 4:18 pm

HI Fego, thank you very much for your reply. You have provided some great feedback and ideas.

After the brewday, I reflected on what had gone wrong and how to prevent this happening on my next brew. I came to the conclusion the majority of the problem was a poorly fitting mesh false bottom in my Colemans coolbox. Although using #30 mesh as a screen, due to the recess near the outlet, grain was dropping past this and making it to the pump.
Yes, I did drain a few litres to minimise blockages. The mesh false bottom was indeed raised about 1/2" from the bottom of the cool box in anticipation of poor flow of wort, and the magnetic pump was fitted correctly regarding to flow, and the valve on the pump output was throttled back and properly primed.

I intend to make additional modifications to prevent further problems in the future:
1. A properly fitted false bottom, with a finer #40 mesh attached to the frame, along with the existing #30 mesh.
2. Fit bolts on the false bottom, for height adjustment, allowing more fluid under the mesh to be available to the pump.
3. Fit fine mesh filters at the exit of the coolbox, and inline with the pump, preventing any grains from entering the impeller.
4. Use a slightly larger pump, which should push any trapped air through the HEX on start up.

Good point also about the fittings being fully air tight! Essential not to be sucking air into the system.

At present I have not used camlock disconnect fittings, only used stainless steel jubilee clips to secure to the barbs on outlets etc. I may have to upgrade in the future when the system is stable.

Do you simply return the wort to the top of the mash tun by laying the return pipe on top of the grain? Or do have some other method.?

On another point, the PID system needs some fine tuning, as the output over ran the setpoint by a couple of degrees. I have kept the spent grain to simulate a real brewing day. So I will attempt to reduce the overshoot as soon as my new false bottom and pump arrives.

Fego, thank you again for your input it was very much appreciated.

Best regards,
Lockwood16

sladeywadey
Hollow Legs
Posts: 377
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Re: Herms build advice

Post by sladeywadey » Mon Jan 12, 2015 6:48 pm

try mashing with 3.5L or 4L per KG until you have got a good feel for HERMS mashing, and definitely restrict the outflow from the pump back to the Tun using a tap on the pump outlet.

For general info, you also need a decent pump in HERMS - the solar ones never worked properly for me and failed repeatedly whilst mashing. The 12v mag pumps that Paul @ Angel Home brew sell are indeed ideal (I have one also). £29 well spent.

The pump needs to be primed properly before turning on. With the inlet and outlet hoses both connected to the pump, and with the pump's inlet hose connected to the tun's tap, and the outlet hose connected to the pump but not yet on the Herms pot, I drop the pump below the level of my tun, open the tun tap until the mash water is well through the pump, close the tun tap then finally connect the hose end up to the HERMS pot. This ensures the pump is properly primed.

I use a braid hose filter in my tun and after some recent problems I had to reinforce the inside of the braid with spiralled copper wire - works fine now. I also use a BIAB bag in the tun along with the braid filter. No grain gets past this ;)

Lockwood16

Re: Herms build advice

Post by Lockwood16 » Tue Jan 13, 2015 10:49 am

Thank you very much sladeywadey for your input too. Waiting for my modified false bottom to arrive from Inoxia with a finer mesh fitted. I too use the mag pumps from Paul at Angel homebrew. Good advice regarding priming, and the slightly higher grain/water ratio's, as well as using BIAB, great ideas!

I will report back after my next brew!

Best regards,
Lockwood16

Lockwood16

Re: Herms build advice

Post by Lockwood16 » Sun Mar 15, 2015 6:45 pm

Just an update on the HERMS system.

I have done a couple of brews since my last post. I have incorporated all of the mods, and have to say that I am really pleased with the outcome. It has solved the problems of stuck mashes, I am using 3.5L/KG although I may drop this down a bit. I have been experimenting with different mash temperatures, although its a little too early to say what difference to the beer it makes, except that seems to be less one dimensional, if that makes any sense.

The other thing I have noticed is that the two beers have come out overcarbonated compared to previous brews using a single temperature mash. Is that because more sugars are extracted? The beers had certainley finished fermenting, as I had checked this out with a hydrometer over a couple of days or so.

Would like your opinions on this, as I will have to change the carbonation levels in Beersmith.

The temperature control works very well, with very little discrepancy between the mash tun outlet temp and the incoming from the HERMS coil.

Will now play around with mash temperatures further to see what differences this makes against a single mash temperature.

What has the more experienced brewers discovered using step mash profiles for ordinary beers? Does it make much difference for fully modified malts?

Best regards,

Lockwood 16

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