How to build a Mash-Lauter-Tun

If you have brewed all-grain batches then you know what I’m talking about and should already have this equipment. However, if you are looking to move to all-grain then this could be helpful. All-grain brewing allow you, the brewer, extra control when creating your beer. You can add body to your beer (without using chemicals like maltodextrin) by mashing at a higher temperature, such as 156F, which creates lass fermentation for the yeast to eat. You can also dry our beer out by mashing at a lower temperature, such as 146F, to create more food for the yeast to eat.

I’ve now successfully built two Mash-Lauter-Tuns (MLT), using two different ways to lauter the wort. The first model I built was a simple cooler conversion using plastic tubing, ring clamps, and a stainless steal braid from a water drain hose. The basic concept behind that model involves removing the drain plug from the cooler and routing the plastic tube (3/8in) through the whole. You then take the stainless steal braid, which you have cut the ends off of and removed the rubber hose from the inside, clamp one end with a ring clamp and then take the other end, place it over the plastic tube and use the other ring clamp to seal it off.  The final step is creating a valve to stop and slow the flow of the wort, I used a plastic clamp from my old siphon. It worked well enough but when I built one for myself I wanted a nicer one.

The second MLT I built was a little more complicated and required more effort, but I personally think it will last longer and do a better job. Here is picture of my new MLT in action mashing my saison.

Materials

1. 1/2 in ball valve
2. 8ft of 1/2in copper tubing
3. 4, 1/2in copper elbow joints
4. 5, 1/2in copper T-joints
5. 2, 1/2in copper threaded joints
6. Cooler (size will determine amount of copper tubing needed and maximum amount of grain that can be mashed)
7. Aquarium silicone sealant
8. Drill or miter saw
9. 1/16in drill bit
10. Brass nipple
11. High temperature resistant hose

The cooler I chose was a 48qt rectangular cooler. The reason I chose my cooler was because it was big enough to do large or high gravity batches and I could find a place to put in my apartment. A 10 gallon round cooler would have been ideal, but it was more expensive and I didn’t have room for one.
Step 1 - Remove the plug from the cooler

 Step 2 -Measure the copper tubing for cutting

I arranged the joints to get a rough estimate of how much copper tubing I needed.
Step 3 - cut the copper tubing to connect the joints. Once the tubing it cut, connect the tubing and place it in the cooler to see if you did a good job. Re-measure and cut if necessary.

As you can see my measuring was a little off at the T-joint that connected the pipe that exited the cooler. Ideally I would not wan the tubing touching the walls of the cooler and you want about an inch between the wall and the tubing. I was too close on the upper left corner. I decided to leave it since it is such a small amount and I don’t have holes there anyway.
Step 4 - Drill drain holes (or cut gaps)

Depending on your equipment you could either cut holes, like I did, or if you have access to a miter saw, you can cut slits to drain the wort through. Either process will work, just make sure that the slits or holes are small enough to prevent kernels from going through. Place your holes/slits about a centimeter apart (more advanced techniques will involve difference distances between cuts to allow for even draining speeds, but I wont go into that). The advantage of a miter saw is speed, it took me about 2 hours to drill all of the holes and I broke 4 drill in the process bits. I don’t have a picture of the holes because I for got to take one. Just make sure, with either design, to cut or drill on all of the tube sections. Some people even cut on the joints, but I chose not too.

Step 5 - Clean and de-bur the tubing
There will be bits of copper that are still attached to the edges of the holes or cuts that need to be filed off so they don’t end up in your beer.

Step 6 - Connect all of the tubing and leak test
Reconnect all of the tubing and place the tubing through the drain hole of the cooler, attach the ball valve using the threaded copper connectors.

Close the valve and add water to your cooler, verify that there is no leaking around the drain hole of the cooler. If there is leaking proceed to step 7, if there is no leaking, congratulations, skip step 7 and proceed to step 8.

Step 7 - Add silicone sealant around leaks

Use a sealant that can with stand high temperature and is safe for humans. I recommend aquarium sealant because it is about $4 for a tube and it is dishwasher safe and does not release any harmful chemicals. It takes 24 hours for the sealant to dry, so plan ahead before you use it.

Step 8 - Add a drain hose or extention

This is to make it easier to drain or lauter your wort into a kettle.

I used the remaining copper tubing

Step 9 - Start mashing!!

The process is not that difficult and allows you to switch to all-grain.  Make sure you place your copper manifold with the holes or cuts facing the bottom of the cooler. I had a higher efficiency using this model then I did using the stainless steal braid version. Update: I have since replaced the copper extension with a brass nipple and a vinyl tube to avoid hot side aeration. So far I've been using this mash tun for over a year and the only problems I've incurred have been pumpkin and accidentally knocking my manifold loose. Initially I had a problem with leaking around the valve but I solved that with a little aquarium sealant.