New HERMS Up and Running

After a long hiatus from home brewing, I finally found some time to put together my herms system - thank you very much 20" inches of unplowable DC-area snow.



I have been brewing all-grain for about 5 batches and have been constantly frustrated by inconsistent mash temperatures, which have led to some malty-belgians and dry IPA’s = time for a herms.

My design is a basic e-HLT with a 1500 watt water heater element and 25 feet of 3/8” copper tubing. I went with 3/8” because: a) I already had the fittings and copper tubing; and b) the flow rate is more than enough for 5 gallon batches (I average about a gallon a minute). To improve heat transfer, I used a 30 gallon aquarium aerator to circulate water in my HLT. It did a great job and is a cheap alternative to a second March pump.

The HLT is controlled by a LOVE TS-13010, which I built into a project box that contains a 20 amp GFI. Again, I had a 20 amp GFCI lying around so why not. To monitor the MLT temperature, I used my Arduino and a LM34 sensor. The serial information is displayed on my laptop via a Processing script. It needs to be tweaked to average out the data a little bit better (maybe take the average of 5 seconds or so of readings).



My mash temperature remained rock solid through both brews this past weekend and I was able to ramp the temperature up at about 1.25 degrees per minute.

Very nice. Where do you have the temperature sensor for the Love controller mounted?

I mounted the temperature sensor for the love about 1/3 of the way down the outside of the heat exchange coil in the HLT. I read a LOT of posts about MLT v. HLT temperature probe placement. Personally, I could only see this being an issue if you aren't constantly recirculating.

Here are my two cents:

The temperature differential between the MLT and HLT is constant and seems to be around 2.5-3.5 degrees (insulated pipes/shorter pipes could cut this a good bit). Thus, with a constantly recirculating system, I only need to monitor the HLT and ensure that the temperature remains about +3 degrees of my target mash temperature. Judging by my last two brews, this method produced a mash temperature that deviated maybe +/- 1 degree - if that. Honestly, with my Beglian IPA, which I did with a slightly thinner mash, the deviation was around +/- .5. Again, the aquarium aerator did an excellent job distributing the heat evenly.

As for the MLT, I used a 4 inch length of 1/4" copper tubing and placed the LM34 about midway down then filled in the tube with some stripped-12 gauge wire. I then crimped and sealed with aquarium sealant and ran a length of telephone cord to the Arduino. The length of the probe allowed me to get a nice average for my MLT-temperature. In the future, I would like to make a copper coil with three LM 34's staggered about 1 1/2" apart so I could get an even better idea of the average temperature. I also use a CPVC manifold on the MLT to distribute the recirculated wort, so the temperature is pretty consistent throughout the mash.

I'll post more pics once I get home.

I will also be adding my ultrasonic element into my MLT once I figure out how to insulate all of the connections.

paddyfunk said:

I mounted the temperature sensor for the love about 1/3 of the way down the outside of the heat exchange coil in the HLT. I read a LOT of posts about MLT v. HLT temperature probe placement. Personally, I could only see this being an issue if you aren't constantly recirculating.

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Interesting but I tend to agree with you that it doesn't matter too much if you're constantly recirculating. My HERMS rig has a lot of similarities. Instead of a HLT, I'm using a dedicated heat exchanger (20' 3/8" coil in a 2 gallon cooler with 1500W element). I mounted the Love temperature probe in a brass T in the mash return line and I maintain +/- 1 degree during a mash. I'm not sure what the temperature of the water in the heat exchanger is, but it doesn't matter.

Again, the aquarium aerator did an excellent job distributing the heat evenly.

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I have the same pump and it works brilliantly. Cheap, easy and effective.

I also use a CPVC manifold on the MLT to distribute the recirculated wort, so the temperature is pretty consistent throughout the mash.

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Cool. I recently put together a CPVC manifold for the mash return, too. I noticed that having a single hose would make for inconsistent readings depending if the hose was pointing towards or away from the thermometer probe I have mounted in the MLT.

Anyway, really nice rig and I'm looking to seeing some more pictures of it when you get a chance. You may have some cool ideas I want to steal.

This type of HERMS solution makes mashing so much easier. No calculating, guessing or worrying about hitting the right temp. Just punch in the number and let the rig take care of the rest.

Lets see the guts of the HERMS and control box!

Snapped some not-terrible pictures this morning. Here is the inside of the herms, 25ft or so of copper tubing (I had two irregular lengths so I had to use compression fittings). I found an adaptor kit for electric heating elements at Home Depot for $.01 (closeout) hence the overhanging neoprene "washer" at the base of the element. I potted the element on the bottom and cut a piece of plexiglass to size and sealed that with JB weld. Just to make sure I also sealed the potted element in GE Silicone II.



And here is an external closeup of the Love controller.



The next thing I want to do is add two additional valves to the HLT and MLT for cleanup and sparging. Then it is onwards in the quest for autonomous brewing.

What did you use for the return line that goes back into the MLT? I have a rectangular cooler also and am trying to think of a way to make a return in the top.