The Electric HLT (or how I built a water heater in a cooler)

A change of methodology in the brewhouse brings the addition of an electric hot liquor tank.

Many thanks to Ken Powers ( for blazing the way.

Electricity can kill you & 180 degree water can burn you I do not advocate doing this project. This is simply my experience. Mixing water and electricity can kill you and burn your house down.
It all started with a 10
gallon Rubbermail cooler
There are many places both
locally and online to find one.
Home Depot often carries them...
A piece of copper from a craft store for the grounding ring.
Drill a hole to fit the ring over a water heater element.
Hole done.
Cut out a ring.
Finished grounding ring with tab
Drill a large hole through the outer membrane of the cooler.
Cut away the insulation.
Drill a hole just smaller than the threads of the heater element.
Using a water heater element wrench (pictured) screw the element, gasket and grounding ring through the hole. Seal well with silicone.
Closer view.
Screw the element tight from inside with a threaded pvc fitting cut to make a nut. Seal with silicone.
Drill and burrow from the side of the cooler for your power cord.
Connect power leads with crimp connectors and soldier the ground wire to the ring.
Seal a pvc cap in place with silicone.
With sight-glass and thermometer added here is the finished HLT.

5 gallons of water were brought to 170F in just over 30 minutes.

We are at 2,500ft, my thermometer is a few degrees off and the thermometer probe is located near the lower edge of the tank. Those three factors, I think, explain why the water was boiling at the end of the element yet the temperature was reading less than 190F.

User Updates

Kremer from the Brewboard sent these great pictures of his grounding ring(s). Thanks, Kremer!

wood on 12/11/07 12:02 am writes
Fantastic. Great. Love it.
Push Eject on 12/11/07 12:12 am writes
Thanks, Wood!
BadRock on 12/12/07 12:02 am writes
That's a great DIY page. I am an Electrician by trade and I really know the importance of a ground ring, I am impressed that you included this in your design, most would have ignored that little detail!
Brew Strong - OUT!
GooberMcNutly on 12/12/07 04:47 pm writes
Two questions:
1) Are there any heat issues around the fitting with either the plastic cooler body or the insulation around the power wires?
2) Do you run this on a GFI breaker?
Push Eject on 12/14/07 12:19 am writes
1) my batches need water no hotter than 170F and no negative effects to the cooler so far.
2) YES GFCI all the way. The entire wortomatic control panel plugs into one. BTW, with the heating element I use I had a new 20 amp service installed just for brewing (and insane Christmas lights).
Kerry on 12/17/07 11:45 am writes
Very nice. I am sticking with my SS Kettle to heat water because with my LP burner I can get to 170F in about 15 minutes. This Gott cooler would be great to maintain temps.
Captain Kangabrew on 01/22/08 05:10 pm writes
How did you mount the thermometer to the cooler, with a thermothingy? If not, I'd like details.

I want something that is removable so I can calibrate the themometer. Thanks!
Push Eject on 02/06/08 02:26 pm writes
Captain, you got it -- the thermosight. Link: Cheers!
Brant on 02/18/08 02:57 pm writes
hey push, heard you bragging about the site on The Network.Great info you have here. I just built your water heater cooler and had a solid test run w/o any ER trips. Thanks for the info.
Push Eject on 02/27/08 12:24 am writes
Now, Brant... c'mon... I never brag. Thanks for the great comment & I am stoked your HLT is working!
Brant on 03/12/08 02:29 pm writes
update: I did jamil's APA last weekend and it was wonderful not having to heat water outside on a burner. now I just have to hook up a timer to it to be ready when I wake up. thanks again.
psi2000 on 05/14/08 05:49 pm writes
How hard would it be to put a thermostat on it so you could set it and forget it?
Push Eject on 05/15/08 12:27 am writes
Psi, that is exactly what I do. A Love Controller (see Binford Wortomatic Control Panel article) maintains temps and its probe fits in a thermowell in the lid.
Vince on 09/24/08 04:00 pm writes
Is that gasket the one that just comes with the element or did you buy a different one?
Push Eject on 09/24/08 04:38 pm writes

Vince, that is the gasket that comes with it.

There is another kind of mount available that I will use when I update this HLT that has a screw-in plate:

Push E.
Vince on 09/26/08 07:49 am writes
I saw those in the store, but i figured they would not be better because you are putting more holes in the cooler...
Push Eject on 09/26/08 11:48 am writes
Good point. However, I think it is a fact that the element will have to be replaced in time and the ability to simply unscrew it and pop in a new is appealing to me.
Linc on 10/31/08 10:43 am writes
Push - The mounting plate rusts. I used it on my early prototypes as well. I ended up mounting the element in the end of a PVC tube. I ordered a brass reducer that is male thd 1 1/2 inches with a female 1 inch. the reducer screws right in to the PVC. I added a T as close to the reducer as possible. So the wort or water comes in one end, flows past the element then out the T, past my thermowell and back to the HLT or MLT. I use duplicate systems for both. I can maintain a 1 degree differential this way. If using gravity I guess you'd have to stick with putting the element in the cooler.

If you use pumps, there is no need to modify or drill the cooler in anyway, just replace the spigot with a ball valve.

brant on 11/20/08 06:31 pm writes
has anyone had problems with leaks under the silicone on the inside of the cooler? I havent had any shorts from it and even roughed up the surface with sandpaper.
vince on 01/29/09 11:47 am writes
linc, so basically you built a rims element for your herms HLT?
Push Eject on 06/14/09 07:29 pm writes
@Linc Haven't seen that yet. Good solution, though.

@brant Not since I remade it with the plate and gasket.

@vince I guess so! :)
BillfromOB on 06/16/09 03:11 pm writes
Love this setup. However, concerning the element size: the largest element for 120 volt I have found is 2000 watt. I was checking on some calculations and for 10 gal of H2O it'll take approx 1hr 17 min to get it to 170. I want to borrow some of your ideas on the brew setup but the questions is how do you go about getting the H2O to strike temp for the mash and then having your HLT up to temp in time to recirculate the mash? Do you heat another 10 gal using your burner and then transfer it to the HLT where the electric element maintains the temp?
thatguy314 on 09/02/09 04:46 pm writes
I love this setup.

I've read reports from people building heatsticks, that the silicone fails on them after about a year or 2. Have you had similar problems?
Push Eject on 09/02/09 07:18 pm writes

I only ever get a leak (and it's a very slow, minor drip) when I fill it up and let it sit overnight. If I fill it and start brewing it is great. I've done dozens of batches now and am very comfortable with this setup.
Peter on 01/23/10 05:52 pm writes
Do you stir while the element is on? Also, how hot does it really get? Dont really plan on getting a temp control just yet, unless you know of something cheap! does it scorch the grains or any ill effect to the actual mash? Thanks!
Peter on 01/23/10 07:16 pm writes
Oh! One more thing! Did you ever have a problem with rusting!?
Push Eject on 01/24/10 05:50 pm writes
Peter, yes. I stir whenever the element is on to keep the temp consistent throughout the cooler. If you don't limit it, it will boil.

Pumping the mash through a coil immersed in the HLT has proved a great way to raise mash temps.

So far, no rusting.
Push Eject on 01/24/10 05:50 pm writes
Peter, yes. I stir whenever the element is on to keep the temp consistent throughout the cooler. If you don't limit it, it will boil.

Pumping the mash through a coil immersed in the HLT has proved a great way to raise mash temps.

So far, no rusting.
Proetus on 02/04/10 03:33 pm writes
So i gathered up all the parts to get this thing together. Bought a hole saw at a cheap discount type store. Mistake #1. Using said hole saw mistake #2. It made 3/4 of a round hole and the other 1/4 broke right off the cooler so i have a semi circle with a bubble on it if you will. So the original method wasnt going to work so i found the plate posted above. Got 4 bolts nuts and washers from the store as well. Punched 3 1/4 more holes in the bottom. (remember the bubble!) Pumped half a tube a silicone underneath it and tightened it up. We'll see if it leaks tmw. Not even gonna bother wiring it at this point. pretty sure its gonna leak :(
Aaron Petersen on 04/07/10 12:18 pm writes
I had a heck of a time getting a seal using silicone, so I took a cue from the cedarcreek heat stick webpage and used JB Weld. That did the trick. Hope that helps someone out.
Joe on 05/03/10 04:32 am writes
Has anyone used JB Weld-Marine? I saw it at Southerlands. It MIGHT be better with liquids. I wonder if it has an oder?
JPZ on 10/11/10 11:35 am writes
I was wondering around how much this setup cost? I wanted to compare it to other setup prices.
Taro on 10/17/10 03:33 am writes
Good grief, I hope nobody else tries this. This whole idea makes me cringe, and I won't even go into the leaching hazards of heating soft plastics. If you want man boobs from synthetic estrogens, have at it. However, that grounding ring isn't going to do a thing for you when the silicone eventually leaks, and it will. Grounding minimizes the risk of current choosing you as a path to ground. It does not eliminate it. If you really need a hot water heater, get yourself a stainless steel pony keg. Have a welding or machine shop weld a threaded stainless fitting in place, and insert your heating element with pipe dope. you still have to deal with exposed terminals, so you would best have them include a plate to allow a NEMA 4 box to be mounted to cover them. Better yet, just get one of those $120 outdoor tankless propane water heaters (like Eccotemp L5) and plumb it in. Get rid of the electricity altogether with the exception of a 12 volt pump. If you don't want to take the advice of a degreed engineer, at least think about this: No hobby is worth dying over or killing one of your kids. You will notice that the National Electric Code was written not by electrical engineers, but by an association of city fire departments to stem the tide of deaths due to electrocution and fire after the introduction of electricity into homes. Something like this could never be sold commercially for a reason. It will kill you in ways that you haven't even thought of. Your kid could be twenty feet away standing on a damp surface when the silicone fails and the nozzle drips. It only takes 1/4 amp to stop a human heart. Your going to have at least 5 or better, depending on your element. Just spend the money and do it right.
Push Eject on 10/20/10 12:03 pm writes
Taro, thanks for your comments. They are truly appreciated in spite of the passive-aggressive arrogance. I tried writing you, but the email address you provided bounced. If you ever want to write an article about this or post a how-to for your alternative electric HLT I will gladly give you a venue here on Wortomatic. Cheers.
Jon on 01/04/11 02:04 am writes
Actually, 100mA is all it takes to fry a human. Also, unless there is laminar flow directly connecting the electricity to the kid, then the kid will be fine. Chances are, however that the leak(s) will better connect the live wire to ground, tripping the GFCI.

Electricity is just as safe as any other method of heating up water (how many of us have electric water heaters in our houses?), but it is also a ton safer to use inside.

Personally, I'd love to have the money to buy a bunch of stainless steel kegs... ain't gonna happen until I'm out of school (Paramedicine, in case you were wondering).

I think Push Eject wrote up a really good, straight-forward "how I did it" tutorial and should be commended for sharing the information, as opposed to being lectured on the faults involved.

Jeff Rocheleau on 04/18/11 04:14 pm writes
I contacted a friend of mine's father who is an engineer for Igloo and asked him about the possibility of leeching toxins. Here is his response:

"It's not really a straight answer because officially we do not recommend putting 170 degree liquids into our chests. There are some potential issues with the foam and if you get close to boiling you are nearing the temperature that will start to (not melt) soften the polypropylene liner. Officially the cooler was not designed to hold boiling liquids. But if they happen to find there way into your cooler it won't poison you! People have done it without issue but I really don't like to see it being done!"

So, ideally, nothing will poison you, but Igloo doesn't recommend doing it. There you go.
Push Eject on 04/18/11 07:16 pm writes
Very cool, Jeff! Thanks for getting that information.

To be clear, I do not boil water in the HLT, but it does approach 175F. You know, now that I think about it, don't most of us mash in coolers? If you do a mash out you probably have the issue, right?

Nonetheless I am considering building a new one like Kai Wallner's at:

Ron Crabb on 04/23/11 07:02 am writes
I did exactly that. I replaced a copy of your orange HLT with a copy of Kal's SS HLT. Your version served me well but I wanted to step up to 10 gal batches so I needed a larger HLT.

I did not use a Blichmann kettle, rather, found a 20 gal SS kettle with lid for $150 shipped.

BTW - taking a SS coil as shipped and reshaping into a tighter coil to function as the HERMs coil (per Kal's pictures) is not a trivial task! Search his forum for HLT coil and you will see some of the ways others were or were not successful.