Dedicated Herms Guide, Problems And Solution Thread

[QldKev]

Got a link to the wiring?

http://aussiehomebrewer.com/topic/72614-my-brew-controller-box/


Obviously this level of wiring is done by a qualified sparky.

 

[dent]

So you've basically got four separate controllers in one box, fair enough. Only trouble I see with people copying that arrangement is that many cheaper/older/crappier houses only have one or two power circuits. But they should know before they start, like you say.

If there truly is only 10A available, this is one way of getting both happening:

(Probably should have used ground symbol rather than earth - it is DC ground)

So the normally closed contact of the relay opens when the HX SSR is activated, preventing the HLT from activating at the same time. When your mash is at rest, the duty cycle on the HX side is quite low, so that leaves plenty of time for the HLT side to get cranking.

The HERMIT controller has the added benefit of making them overlap a little if desired, so you can push your luck some or use a 15A outlet for instance.

 

[Burt de Ernie]

Alrighty.....Im gunna throw my hat into the ring.

I know it would be a lot more intelligent to learn from the more experienced players on AHB however for some unknown reason I always have to be different.

After reading all these HERMS posts for which I am most impressed, I have decided to retrofit a HERMS setup to my rig however my rig is not electric. My heat source for mashing is a LPG Rinnai instantaneous heater.

Based on this I have had to come up with something which I believe is totally unique (if anyone has seen this before please link so I can learn from others mistakes). Instead of using a S/S pot and coil I have found myself a 500mm piece of type B copper (actually I got it from a plumber mate of mine).

This is the sketch diagram of my proposal.


These are some of the components


Basically the Rinnai will keep 85 degree water circulating over the herms coil. I had to use copper as the flow and return loop is under 250kps of pressure. At this stage I am going to have to use a series of 1/2" copper elbows to turn the herms coil at the ends which will allow me to get 5-6 meters of 1/2" pipe into the 100mm copper.

FYI...this is a pic of my rig currently



Before I make this thing does anyone have any input?

 

[dent]

A couple things:

As usual the probe should be on the output of your heat exchanger. In your case, with the possibility of no flow, in the output but also under the mash liquor.

I guess you're using the thermostat to turn the pump on and off. OK. Only real problem I see with this is the wort sitting in your heat exchanger will probably get hotter than you'd like when the pump is not running. So you may have difficulty getting the expected attenuation on your ferments. Or it might be just fine.

Does the instantaneous heater just go on/off or is there some kind of proportional control?

 

[Burt de Ernie]

Dent,

Yes you are correct....the thermostat controls the pump.

The instantaneous heater/Herms vessel temp (IE the flow and return loop) can be set to 50, 60, 65 75 or 85 degrees. It is setting adjustment built into the heater.

In relation to the wort sitting in the HEX when not circulating....this is a fantastic point you make. the answer is to locater the herms vessel above the MLT. This will ensure the wort drains from the pipe work when the pump stops running...Thanks.

With the location of the probe... I am confused. My understanding is that the MLT temp would stipulate when the pump runs....

 

[dent]

Yeah but by the time the probe gets heated up, half your mash is over your set temperature. Since you're mainly interested in the highest temperature of the system as far as enzymatic conversion is concerned, putting the probe at the hottest point, and the point that is quickest to respond, is considered best.

Even with the HX held over the mash, the only way your wort will drain out when the pump isn't running is if your tube is a large enough diameter, and the outlet held over the mash (with an air gar), to allow a bubble to traverse all the way up your tubing. Even then, when it gets to the top of the first loop it will stop, so you'll still have a bunch of wort trapped in there.

 

[Burt de Ernie]

Noted about the probe.

I was thinking wort would syphon backward similar to when I empty my fish tank for cleaning.

In any case if a portion of wort is heated to 85 for to say 5-10 mins, this would be similar to decoction. As long as the grain is not subject to that heat, then tannins would not be released.....of course this is what I imagine.

 

[dent]

It would syphon if the bottom end was allowed to leak air in, but since you've got your pump etc attached that would be undesirable.

The overheating isn't a tannins thing - I'm thinking degradation of beta amylase. But it will probably be fine in the end anyhow.

Sounds like it will be a pretty good and fast system when you get it all going.

 

[Burt de Ernie]

Dent,

I appreciate the feed back as I`m a little noob at all this.

I will post some more pics of the build as it comes along over the next few nights.

 

[QldKev]

I think it can work. I see by having the return open it can siphon back on itself from the outlet, hence draining most the wort from the heat exchanger. The issue here I see is we normally measure the wort existing the heat exchanger for a temperature reading and control. If you are stopping the flow and allowing it to drain back you no longer have anything to measure at that point. Measuring the temperature in the grain bed is bad, as the grain bed will always lag when ramping up temperatures, hence you will be pumping out wort hotter than the set point possibly denaturing a lot of the enzymes.

I think a better design would either control the heating source (as in a traditional heat exchanger) or build a hot water bypass for the heat exchanger. So the water from the hot water system bypasses the heat exchanger and goes directly back to itself. Therefore the wort is pumped constantly.

I do see an issue with either system for the HWS. As the wort gets close to the set point the HERMS controller will cycle the heating source more frequently. I'm not sure of the HWS will like heating for a couple of sec, then being turned off for a couple, then on again etc. But that may be how they work anyway to be able to get the desired set points.

But by the time you have a solenoid valve to control water flow and a pump for the how water system, it seems easier to add in a heating element into the heat exchanger as per a traditional HERMS and just keep the HWS acting as a HLT for strike water etc.

I would not build the heat exchanger too big with a lot of pipe in it. As small a heat exchanger that can fit 2-3m of copper would be heaps.

 

[Burt de Ernie]

Kev,

since my conversation with Dent last night my thinking has changed.

Based on what you and dent have said, I will flow the wort continually during the mash. The temp control will now operate the flow and return pump instead and the discharge for the Hx will discharge over the thermowell.

Based on this arrangement, the biggest issue I will have is once the flow and return pump stops operating there will a residual amount of heat remaining in the Hx that will be discharged over the mash.

Dependant on the size of the batch and the efficiency of the Hx I may lower the flow and return temp to assist with this issue.

 

[dent]

You're right Kev, I had the syphoning thing ass-about. It will probably screw up the grain bed, and lautering clarity every time it backflows though.

 

[QldKev]

Kev,

since my conversation with Dent last night my thinking has changed.

Based on what you and dent have said, I will flow the wort continually during the mash. The temp control will now operate the flow and return pump instead and the discharge for the Hx will discharge over the thermowell.

Based on this arrangement, the biggest issue I will have is once the flow and return pump stops operating there will a residual amount of heat remaining in the Hx that will be discharged over the mash.

Dependant on the size of the batch and the efficiency of the Hx I may lower the flow and return temp to assist with this issue.

The residual heat is why I was recommending downsizing the heat exchanger, the smaller the thermal mass the better. If you look at the herm-it coil it's about 3m and stainless which is no where near as good as a conductor as copper, but can handle 2,000w worth of heating. By keeping the copper pipe to 3m max in the heat exchanger, and keeping the overall volume as small as possible you will minimize overshooting. Overshooting is often not that bad as the grain bed always lags behind the HERMS outlet. You may stop the heating process at the set temp and the residual heat will try and pull up the extra temperature, but you will find once you stop heating and with the cooler wort from the bottom of the grain bed being fed into it the heat exchanger will lose the heat rapidly and most likely need to commence heating pretty soon after. I still think it's easier to use an element in the HERMS, is there a reason you don't want to go this way?

You're right Kev, I had the syphoning thing ass-about. It will probably screw up the grain bed, and lautering clarity every time it backflows though.

Good points about the clarity and disturbing the grain bed.

 

[Burt de Ernie]

Kev,

I agree the electric HERMS may be easier and there is always the option of taking that path however, I just like trying different things. Combined with the fact that I was a plumber and am now a hydraulic consultant I like the idea of dusting off the old oxy/acetylene bottles and using the plumbing skills to construct this thing.

So far the materials have cost me nix because I know a lot of plumbers.

Edit...the Hx has cost me nothing......the rig was a little more ;-)

 

[Beerisyummy]

F me. You boys are always coming up with new ideas and nutting them out. Snaps!
I've thought about nabbing one of the instantaneous heaters, but I'm waiting for an LPG jobby.

On a side note, I'm looking at moving the HX one step closer to the Kettle/Mash tun. At this point I've been using the plate chiller as my HX, so it's not a big step to move the HX either into the MT or come up with a jacket style solution.
I'm sure this has all been done before, so throw me a bone and save some time if possible.

If I make a roller jig to roll out my annealed copper into a coil that has a flat inside, and then wrap that around my kettle with some insulation, will this work? The easy way is to drop the heating coil directly into the wort and use it for chilling also. I'm toying with cooling/heating the kettle itself.
I've got nearly a third of a square meter of stainless steel on the kettle to play with during a brew. Not bad odds with the whirlpool running.

PS. Did I mention I don't want many vessels.

 

[Hugh Jarse]

Hi All
Slowly collecting bits and pieces to enter the exciting world of HERMS.
Would like to go with 15l into the FV (small I know but I would like to sample different varieties before racking up some stable house beers) but I have plenty of room for future expansion. 3V setup, at present 50lt SS HLT, 40 lt esky MT and about to take possession of a 32l SS Boil Kettle.

My electrical knowledge ends at the point that I know to unplug the toaster before sticking the knife in to remove the well burnt bread!
My welding and soldering knowledge ends at: thats a welder and thats a soldering iron.

I am thinking about purchasing the HERMS coil kit from Gryphon and the TempMate controller from CraftBrewer and installing in a PVC tube with a 26cm 2400W heating element. All running through one of the Magnetic Drive pumps from National Home Brew (already purchased) (pump will also double as ice water pump to run through immersion chiller for dropping to pitch temp after tap water has run its course). Would like to be able to run the 2400W element and the pump from a single extension cord from a single power point on the house. Kettle is gas fired (at this stage)

My questions relate to the HERMS coil kit and TempMate controller. I will eventually go down the PID route but will not be for quite a while and am happy to do single infusions and batch sparge.

Any comments on the TempMate controller and how it performs? I see reference to them in this thread but nothing too much in way of performance as seems PIDS are dominating the scene.

Also, any comments on the HERMS coil kit from Gryphon? My only real hesitation is the price, but the more I justify it to myself the closer I get to making the click of the mouse. Always easier to ask for forgiveness than permission…….

Also, welcome any comments on rig etc…..
Cheers
HJ.

 

[Camo6]

I run a Herm-it coil in a 4l vessel with a KK element and get decent ramp times for single batches up to 30l. When I shopped around I found Nev's prices to be quite reasonable considering it was SS. I couldn't coil SS tube that tightly without the chance of kinking it. I'd love his new vessel but have spent too much on this hobby lately so will have to wait a little while.
I run both my HLT and HEX on STC1000's. I use the standard STC sensor in Nev's thermowell and a craftbrewer SS sensor in the HLT. Both maintain very accurate temps. More so than my old BIAB mash temps. I am upgrading to PID's but only because I'm an addict. I reckon your tempmates will be fine for the interim.
Personally, I'd swap your HLT with your kettle. Your HERMS element will reduce your HLT requirements and a bigger kettle will increase your batch size.

 

[Hugh Jarse]

Personally, I'd swap your HLT with your kettle. Your HERMS element will reduce your HLT requirements and a bigger kettle will increase your batch size.

I was thinking this in the long term when I start running full batches for house/lawn mower beer. For the interim it will stay as is due to the HLT having the therm and ball valve already installed and gas fired.
I think the price for the Herm-It coil is quite good, just have to justify the initial outlay against copper and my limited handy skills with fittings etc (still yet to install connections on the immersion chiller so the hose clamps don't leak, its only been a year now).
Cheers for the input and advice.

 

[Camo6]

No worries HJ. I did all the maths initially too. Yeah I coudl've done it a lot cheaper in copper and brass but as I ordered more and more miscellaneous SS fittings it seemed criminal to add anything but stainless to the system, regardless of which is more efficient. Back then I was running a BIAB system and had the luxury of gradually obtaining parts and burning the receipts as I went.

 

[Burt de Ernie]

I think it can work. I see by having the return open it can siphon back on itself from the outlet, hence draining most the wort from the heat exchanger. The issue here I see is we normally measure the wort existing the heat exchanger for a temperature reading and control. If you are stopping the flow and allowing it to drain back you no longer have anything to measure at that point. Measuring the temperature in the grain bed is bad, as the grain bed will always lag when ramping up temperatures, hence you will be pumping out wort hotter than the set point possibly denaturing a lot of the enzymes.

I think a better design would either control the heating source (as in a traditional heat exchanger) or build a hot water bypass for the heat exchanger. So the water from the hot water system bypasses the heat exchanger and goes directly back to itself. Therefore the wort is pumped constantly.

I do see an issue with either system for the HWS. As the wort gets close to the set point the HERMS controller will cycle the heating source more frequently. I'm not sure of the HWS will like heating for a couple of sec, then being turned off for a couple, then on again etc. But that may be how they work anyway to be able to get the desired set points.

But by the time you have a solenoid valve to control water flow and a pump for the how water system, it seems easier to add in a heating element into the heat exchanger as per a traditional HERMS and just keep the HWS acting as a HLT for strike water etc.

I would not build the heat exchanger too big with a lot of pipe in it. As small a heat exchanger that can fit 2-3m of copper would be heaps.

Ok,

Taking on board the advice from Kev above I have reworked my system.

I now have a HERMS system with a total volume of 1.9 litres and 4 metres of coil. Basically the wort will circulate through the center of the Rinnai flow and return pipework.

One of the good things about this system is after the boil I use the same HERMS coil as the chill just by turning the heater off and opening up a discharge valve.

I have also converted a new mash tun that draws off the base of the mash which will increase mash efficiency. One of the things I was most stoked about was the $5.00 stainless false bottom I got from woolies.

The only thing I am not sure of yet is the best position for the probe. Like Kev said the pump may not like the probe being on the return line into the keg as per a regular HERMs setup. Based on this I have installed 3 thermowells into the system two of which are home made. 1 on the wort return, another on the wort flow line and the last one straight into the mash tun. Time will tell.

Below are 2 you tube links demonstrating the system.





Happy to hear all feedback good and bad!