$50 Dedicated HERMS

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poptarts

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I will be documenting my new HERMS system build here. First off, I'm a cheapskate, so this is an extremely budget HERMS build. My plan is that for 50$ or slightly more depending on what I have lying around the house I can add a HERMS to my build. The 50$ price tag assumes you have a pump. But the price includes:
Heating
Coil
Automation


If you dont have a smaller pot lying around go to your local thrift store or pick a new one up at Walmart for 7$


From the 4 Items in the images I'm assuming most of you can get an idea of the final product. I will be making this and testing it soon, items are already ordered. If I'm right this will be a super inexpensive way to add HERMS to your brewery at a cost cheaper than most PIDs so we will see.
:mug:

If your a dumb american like me and have to use F instead of C for everything this could come in handy to tape to the pot as well.
 

Ramitt

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Interesting idea, does 8 qts have enough thermal mass to be effective?
 
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poptarts

poptarts

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I hoping the less thermal mass the better actually. The less water the faster the burner can swing temps around.
 

KegWrangler

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I ran a few quick calcs...

Looks like the hot plate is 800W. If the 8qt pot is full of water in the range of 160*F and the heat transfer between plate and pot is 100% you could raise the temperature of the 2 gallons in the pot ~ 2.5*F every minute.

So If you are running 150*F wort through the HERMS at 1gpm you should be able to step about 5*F per minute (assuming perfect transfer of heat from Plate to pot through HERMS, etc). Unfortunately this would be the temp gain of that 1 gallon so the mash temperature increase would be that divided by the total mash volume (1*F/min for a 5 gallon mash, 0.5*F/min @ 10gallons...etc).

If you intend to use the HERMS to maintin temp and set your HERMS temp to match then more thermal mass is better. However, as it sounds that you want to be able to step the temperature up quickly, a smaller thermal mass sounds right.

Anyway, good luck...I am interested to see how the real world results turn out as I have been prepping a similar build but with a 1500W water heater element in a 3 gallon pot (running 2/3rds full for smaller thermal mass).
 

BadWolfBrewing

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What size and material is your mash tun? What size / length is the copper tubing? Finally, which pump do you use? Sorry for all the questions, just curious is all.
 
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poptarts

poptarts

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I have a 10 gallon igloo cooler for a MLT
Copper tube is 10' x 1/2"
I have a chugger pump.

I will post a ton of pics and a lot more detail when I get to building and testing this. Ask away though I will answer what I can.
 

Docbruw

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Is that temp controller going to be able to hold a consistent water temp? It doesn't have the "fuzzy logic" that a PID uses to hold temperatures.
 
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poptarts

poptarts

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All part of the experiment. To be honest my biggest concern is going to be if the 800w burner will produce enough heat to budge the temp. stc-1000 will hold within .5C and since im using a cooler I cant see the temp singing around all that much.
 

BadWolfBrewing

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Fuzzy logic isn't necessary, but the pid control helps a lot. The stc style controllers use a hysteresis control law, which don't do well in systems with big delays. However, I use a hysteresis controller on my sous vide machine and its fine.

I'd start thinking of ways to keep the water in the herms vessel moving. One of those little tan pumps, agitator, something like that. That will compensate for the simple control law, and make for better heat exchange too
 
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poptarts

poptarts

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I will be checking temp on the return out of my hex, I don't know what all this delay stuff your talking about is. The wort is either at temp so do nothing, or the wort needs to heat up, so turn on the burner. I feel like it will be that simple. I will have a gallon or less if I can water in the pot the amount of lag seen from that should be very minimal.
 

BadWolfBrewing

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I'm curious to see how it works. The fact that your MLT is a cooler certainly makes things easier, in that you aren't having to work as hard to replace all the thermal losses of a big stainless pot. I think agitating the water in the HERMS vessel will still help a lot. If you don't, there will be a 'skin' of cooler water next to the coil, and your heat exchange will be reduced a fair amount.

When you say checking the temp, does that mean you are going to put the STC sensor on the HEX return line?

As a note of caution, if that is the case, be careful about heating when you aren't recirculating. If the wort isn't moving, the temp of the HERMS exit will droop. Your controller will keep the hotplate on, but the temperature sensor will not really show a change, as new heated wort isn't being moved past it. Before you know it, the HERMS vessel will be boiling.

Excited to see how this works out. I think if you get good results, you'll get a lot of people following your lead. Keep us all posted
 
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poptarts

poptarts

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I'm curious to see how it works. The fact that your MLT is a cooler certainly makes things easier, in that you aren't having to work as hard to replace all the thermal losses of a big stainless pot. I think agitating the water in the HERMS vessel will still help a lot. If you don't, there will be a 'skin' of cooler water next to the coil, and your heat exchange will be reduced a fair amount.

When you say checking the temp, does that mean you are going to put the STC sensor on the HEX return line?

As a note of caution, if that is the case, be careful about heating when you aren't recirculating. If the wort isn't moving, the temp of the HERMS exit will droop. Your controller will keep the hotplate on, but the temperature sensor will not really show a change, as new heated wort isn't being moved past it. Before you know it, the HERMS vessel will be boiling.

Excited to see how this works out. I think if you get good results, you'll get a lot of people following your lead. Keep us all posted
I would prefer to leave out any water agitation just because it will up the price. If it doesn't work well I will start swapping things around and adding things, that included. Yes I do plan on adding in the sensor for the stc some where in the return but I plan on keeping the wort recirculating the entire mash so I shouldn't get any "stale" reads.
I think everything but the copper should be arriving today so I can at least get the stc all wired up and find a spot on my stand for the hot plate. I might run a test to see how fast the hot plate can boil a gallon of water as well if I find the time.
 

MikeInMKE

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Energy in the form of heat does not move instantly from hot plate to kettle, to water, to heat exchanger tubing, to what is flowing inside the heat exchanger tubing, to the temperature sensor. Heat moves quickly through some materials, and slowly in others, but in no material does it move instantly.

Those delays will add up and cause an overshoot of your desired temperature as it's heating up, and then an undershoot as your controller is waiting for the temperature sensor to cool back down to the desired temperature.

PIDs are designed to solve this problem, which is why they exist.

Think of it this way: You are in a car and need to get from point A to point B. You mash the throttle to 100%. When you reach point B, you shut off the engine and coast to a stop. You will overshoot point B. What you need to do is take into account where you are in relation to point B and transition off of the throttle before you get to point B.
 
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poptarts

poptarts

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I plan on pumping wort threw the hex at a reasonable enough rate where the variable temp between water in the herms pot and mash temp should be very small. So picture me driving my car at .5 mph then shutting off the engine, going to go what? 5 feet?
 

opiate82

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Interesting experiment. If you do get it all working, please post pictures/info of your mash tun build as well. :)
 

BadWolfBrewing

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I plan on pumping wort threw the hex at a reasonable enough rate where the variable temp between water in the herms pot and mash temp should be very small. So picture me driving my car at .5 mph then shutting off the engine, going to go what? 5 feet?
The difference between the herms pot and the MLT will be due to losses to ambient of the MLT more than anything. If you were using a stainless MLT, I'd be skeptical about how well it will work.

But in a cooler, the hot plate / heat exchanger should be able to keep up with it.

If you were measuring the MLT outlet for controlling the hot plate, I'd be skeptical too. This is the delay I was talking about, and the metaphor about the car was made by another member. If that was the plan, it wouldn't work well. You could have boiling water in the herms pot, and it would take a long time before the sensor recognized that the MLT was heating up. You'd be risking heating up the mash too much, and potentially denaturing the enzymes.

But, measuring the output of the HEX and closing the loop with that should null out that problem. It will introduce a different problem, in that the outlet of the HEX will be hotter than the mash. But, mashing in a cooler, that problem is negligible. And if it does seem like an issue, you can just command a higher temp by a degree or two.

Sorry, I can't stay away from these topics. Welders love talking about welding, the biologists go in depth about yeast propagation, etc... I'm a controls engineer, and this is one of my favorite aspects to the hobby.

:mug:
 
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poptarts

poptarts

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Burner and STC arrived today, got them mounted wired up and got to play for a little bit. Still waiting on my hex coil though.


So some good news the stc will hold with .3C not .5C like I was thinking so that should give us even more control than I had expected. The burner heats up quick and gets crazy hot. I had it set to high and got a gallon of water up to 50c in like 10 minutes maybe from 20C. so sounds like it will be able to sing our temps around at a reasonable pace and the stc handled the ~8 amp load with no issues that I noticed. I will keep everyone more up to date when the hex comes and I can see how tight it will hold water temps. After playing tonight though I have even more faith this will work than I did this morning.
 
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poptarts

poptarts

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So had a thought too, a bulkhead to this pot it would be 1 gallon biab system and the hex could be the chiller for it. I would be able to recirculate and hold mash temp with the stc then just boil in the pot. Might be worth trying once this project is all done since I have one of those pumps lying around. Would be a fun little pilot system.

Finally got a tracking number on my coil. I believe it should be here next week so I can start doing some real testing.
 
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poptarts

poptarts

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Modding the brew stand to make from for the herms pot
Temp probe is long enough to reach bottom of MLT so should work well regardless of mash size.

1396741433478.jpg
 
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poptarts

poptarts

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Modding complete just waiting for coil if all goes to plan I will brew next weekend.

1396802526394.jpg
 
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poptarts

poptarts

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Coil will be here Friday according to tracking, so hopefully the 12th I can run a few water tests. Anything specific you guys want data on? I was thinking on just putting like 5 gallons in my MLT and seeing how fast I can raise the temp and see how steady I can hold the temp.
 

gstrawn

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I'm watching this very closely as I'm a broke college students and can a afford the more traditional electric HERMS setup I dream of. I could probably afford to do something like this with things I already have lying around. How are you plumbing the HERMS coil through the pot? Are you using bulkheads?


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poptarts

poptarts

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I'm watching this very closely as I'm a broke college students and can a afford the more traditional electric HERMS setup I dream of. I could probably afford to do something like this with things I already have lying around. How are you plumbing the HERMS coil through the pot? Are you using bulkheads?


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No holes in the pot. going to just coil up the copper tubing as small as I can and slap some silicone hose on each end. Ideally I can coil it like this:

So it is completely flat and just one layer high so I only need a few cups of water.
 

gstrawn

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No holes in the pot. going to just coil up the copper tubing as small as I can and slap some silicone hose on each end. Ideally I can coil it like this:

So it is completely flat and just one layer high so I only need a few cups of water.

Awww super simple solution. I like that. Are you using any quick disconnects with pump or just sliding it on and off a barb? I really hope this is effective for you. I'm really excited to see the results. Did you already have a sparge arm in your mash tun?


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poptarts

poptarts

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Slide on and off hose barbs, they hold well for me I don't even use hose clamps. and I plan on drilling a hold in the cooler lid and just tossing in a few feet of silicone tubing and coiling it on top of itself for the return. At the end I will have the temp probe as well.
 
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poptarts

poptarts

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Plus also if this works my MLT will double as a sous vide oven! I'm actually really excited about that.
 

gstrawn

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Plus also if this works my MLT will double as a sous vide oven! I'm actually really excited about that.
haha, not many brewers probably double their mash tun for that. I was telling my girlfriend about that and she thought it was weird. If I just went and made a sous vide oven she'd have no choice but to try it!


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Carlscan26

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I've been considering a similar idea but with an insulated water urn/coffee similar to this one: http://www.amazon.com/gp/product/B007B64P7A/?tag=skimlinks_replacement-20 (insulated and 950 watts)

Or this one that's not insulated and unknown wattage: http://www.amazon.com/gp/product/B000RVG9D4/?tag=skimlinks_replacement-20

Basically looking for a similar size (8 qts give or take) with the biggest burner possible, filled as little as possible (1 gal ideally in my head). But more integrated than a separate pot and burner.

Very interested in your results especially if the controller will maintain the wort temps within 1 degree F.



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poptarts

poptarts

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Yea I looked at those too but the burner and pot were cheaper and had generally better reviews.
 

MaxOut

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If your using the HERMS primarily to raise temps for step mashing I would manually control hot plate to be at or near boiling with the lid on to reduce evaporation and use the STC to control the pump with STC monitoring temps in the mash tun return. This will give you the quickest temp steps hands down. Constant recirculation has a natural cooling effect when lines are exposed to ambient temps and you will find that temps in your HERMS will need to be a couple degrees above the desired target MLT temp to maintain temps. Most cooler style mash tuns will hold temps within a few degrees for the length of a mash so constant recirculation without the need to raise temps will result in greater fluctuations in my opinion.


MaxOut Brewstat
 
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poptarts

poptarts

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Yes but the whole point of this build is to have a very small thermal mass so even if I did fill up the pot with 2 gallons it would take a long time to heat that up to boiling and I'm not sure that would be enough thermal mass to swing the temps in the tun more than 15 degrees maybe. Also with more water in the pot I will get more heat stratification that I don't really want to mess with. I will be happy to test it out for you though if you are interested. Although it looks like your system and garage totals about all my life assets so I doubt it haha.
 

MaxOut

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My system was built to maintain temps in an uninsulated MT so thermal mass in my HERMS is what I was looking for. Step mashes where not my priority but can use HERMS and direct fire MT if I want to step.Based on your posts you are looking to do step mashes correct?


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