Homemade HERMS with Bottom Drain MLT

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Like many of the homebrewers I know, I started my own adventure in homebrewing with a single brew pot making extract brews on the stovetop. After the success of my first batch of "Multigrain Red", I was hooked. More than eight years, and hundreds of gallons later, I can't imagine many hobbies more fun and rewarding then making my own beer. Its been said that if you buy a man a beer, he might buy the next round, but if you teach a man to brew, there will always be beer around!
The only thing more fun than making beer, is sharing it with my good friends and family, and I'm proud to say that after a few pints of my brew, more than a few of my friends have started to brew their own. Which is a good thing, because I can't seem to keep enough on tap. When people ask me if making beer is hard, I tell them that if you can boil water you can brew beer. The hardest part is waiting for your brew to be ready to drink!
Over the years I've come to enjoy working on my brew rig as much as I enjoy brewing the beer. I spend lots time browsing the threads and discovering what other people have put together, and then use those ideas to make my own system better. These days you can buy all kinds of fancy brew equipment right off the shelf, and as home brewers we are fortunate to have such incredible resources at our disposal. But for me, I enjoy the DIY aspect of brewing, and try to make as much of my own stuff as my schedule and budget will allow. The brew setup detailed in this article is the result of years of trial and error, researching, experimenting and trying different things. In the end it doesn't matter how fancy or complicated your brew rig is, what really matters is the brew coming out of your tap (or bottle) at the end of the day. This setup works well for me, and consistently cranks out tasty brew ten gallons at a time.

My setup is a natural gas fired single-tier HERMS (Heat Exchange Recirculated Mash System) with two burners. Perhaps the most unique part of my rig is the bottom-drain Mash Tun, an idea that I first read about here on the forums. I love all-grain brewing, but I loath the clean up. After a long brew session, much like my grains, I'm spent, and I want to clean up quickly and relax. The main benefit of the bottom-drain Mash Tun in my mind is ease of clean up. I use three kettles (Boil Kettle, Mash Tun & Hot Liquor Tank), and only the Boil Kettle needs to be lifted off the brew stand for cleaning. The other two kettles are clean-in-place. One of my goals in designing this rig was to save my back and minimize the heavy lifting. After the sparge is complete, and the boil has started, I simply scoop the spent grains out of the Mash Tun using an old soup bowl until I get down to the false bottom. Once I can see the false bottom, I pull it out, and then remove the bottom drain valve. The remaining sticky grains and crud are simply rinsed out the bottom.

You can see in the photo that the "bottom drain" is achieved by using a 2-inch tri-clamp x 1/2-inch NPT adaptor secured to the top of a Sankey keg. A little confusing because the bottom drain is actually attached to the top of the keg, which is inverted on the stand.
Having a bottom-drain mash tun with attached valve the way I have meant that I could not use direct flame on the Mash. For this reason, I decided to go with the HERMS setup. I already had a good length of copper from an old immersion chiller, so all I really had to do was make a few holes in my Hot Liquor Tank, and plumb it in. After making hundreds of gallons of beer using the HERMS coil, I would never go back to a direct-fired Mash Tun. In my opinion there are many benefits of using a HERMS, including: only two burners required (which saves some $$), no risk of scorching your mash, and easy control of more complex step-mashes, to name a few.

Like my Mash Tun, the Hot Liquor Tank (with internal HERMS Coil) is also clean-in-place. Because the Hot Liquor Tank only has water in it, all I need to do at the end of the session is make sure its empty and dry. The HERMS Coil is easy to clean by flushing with hot water, then cleaning solution, then again with hot water. Bam, Done. Truth be told, the Boil Kettle could probably also be cleaned on the brew stand, but I prefer to set it on the ground where I can more easily get in there and scrub things out and give is a good rinse.
Full details of my build can be found on my build thread here, but here's some highlights and thoughts on the process:
The brew stand itself is made from 1 1/2-inch square steel tube, which I welded together using a MIG welder with flux-core wire. I was unable to find enough scrap steel of the same size to make my brew stand, so I bought the steel tube new. At $160 this is the single most expensive part of my whole brew setup. Originally I was planning on making a two-tier stand, using gravity to drain my Hot Liquor Tank, but then I stumbled on a second-hand March pump in town for cheap. Now that I had two pumps I could build a single-tier stand, which was easier to weld, and required less steel tube. The brew stand is very stout, and I'm very happy with the way everything turned out. It may not have "bling" like many of the amazing brew rigs you can find in the forums, but it gets the job done, and I have the satisfaction of saying that I made it myself. To anyone considering welding their own brew stand, I say DO IT! I am fortunate to know a few very skilled welders who offered me some help in learning how to put something together, but when it came time to build the brew stand, I was on my own. There are lots of great resources online, and at the library for anyone thinking about welding their own stand.

As mentioned before, my setup uses three kettles, all of which are old half barrel Sanke kegs. If you can acquire Sanke kegs legally and ethically, I think they are the way to go. Even if you pay top dollar, they are still much less expensive than commercially built brew kettles of the same thickness or quality. I really only needed two tools to make the basic kettles: an angle grinder, and a drill with a step bit. Of course I used a few other tools to make the finished product, but the point I'm trying to make is its not hard to modify a Sanke keg to make a kettle, or "Keggle". I cut the tops off (or bottom, in the case of my Mash Tun) using an angle grinder with a cutoff wheel. I drilled the holes for the drains, thermometers and sight glasses using a simple step bit (slow speed, lots of pressure). If you are using bulkhead fittings, that is basically all you need. Some of the fittings on my kettles were welded by a very skilled guy in town who does welding for all the breweries, but that was accomplished via trade (for beer, of course!), but most of them are weld-less bulkhead fittings.

My brew stand is fired using two natural gas "banjo" burners. Propane is expensive, and you have to remember to fill those tanks all the time. If you live in an area where natural gas is available, and you don't want to build an electric brew rig, then I strongly recommend using natural gas. The supply is virtually inexhaustible, and at least where I live, the price is very reasonable. The bottom line is installing black pipe is very easy, and inexpensive, but you have to take great care with this project. The consequences of hooking up your own natural gas incorrectly can be very dangerous to you, your family and your neighbors. Always consult with a professional plumber before doing anything with the natural gas in your home.
A typical brew day goes a little something like this: FIRST: fill the Hot Liquor Tank with water and start heating. It is important to heat the full HLT first because you want this water to be at least 180 deg F before you dough-in for single infusion mashes. Once that is going, I measure and heat my strike water in the Boil Kettle. When the strike water is up to temp, I pump it over to the Mash Tun and mash in. After a few minutes, if the temperature is a little low, I simply start circulating the mash through the HERMS coil. For step mashes, simply pump the mash through the HERMS for each temperature increase in the recipe. If the water in the Hot Liquor Tank is 190~200 deg F, it will raise the temperature of the mash very quickly when using the HERMS. When the mash is done, I circulate using the HERMS until I reach mash-out temp, and then direct the hose into the boil kettle for sparging.
After the boil has started, and the grains have had a little time to cool off, I scoop them out of the MLT until I can see the false bottom, and then remove the false bottom and drain. Using any remaining sparge water left in the HLT, I rinse out the Mash Tun. This is one reason that I always fill the Hot Liquor Tank full, so I usually have enough water left over after the sparge to rinse out the MLT. Once that is done, I secure the bottom drain, and enjoy some homebrew while the wort is boiling.
When the boil is finished, and it is time to cool the wort, I collect the hot water coming out of the chiller in the MLT. If the water is not very hot coming out of the chiller, then I collect it in the Hot Liquor Tank and heat it up a little. Either way, the "waste" water from the chiller is used to rinse and clean the HERMS coil, pumps, and Boil Kettle.
Basically, in a beer nut shell, that's about it. I enjoyed building the rig as much as I enjoy brewing with it. I think this system is fun and easy to use, and can be built with a little head scratching by anyone with a few tools and a little help. As always, my sincere thanks to other member who have taken the time to post details of their builds, without whom, none of this would be possible.
Very nice write-up and thanks for the details for an average layman like me. I'd like to go HERMS one day. I'm assuming I can just keep my round Igloo and just install a coil in my HLT to save a little cash.
Looks and sounds great, I may look into the bottom drain mash tun for my HERMS system too - easier and faster cleaning is perfect for someone lazy like me. One thing I was wondering is, does your false bottom move around? The side discharge plumbing for my system holds it pretty secure and prevents it from moving. Is yours just sitting there unattached?
Some great ideas and a nice system. I will be looking into the HERMs setup more now. Although the waiting til the boil to enjoy a homebrew probably won't work on my system!
@BungBrewing: My false bottom does not move around in the bottom of the keg. I have a thread somewhere on the forums about making the false bottom. It is two pieces, and when folded flat fits snugly against the inside of the keg. I'm sure any of J-Bird's false bottoms would work great for this type of Mash Tun.
@beernutz: My brewhouse efficiency with this system has always been up around 80%. I use Beer Tools to scale recipes, and have had great success!
Do you have a materials list for your build? I'm particularly interested in the insulation and jacket materials.