Craft Beer Brewing

Home Brewing – Mash Tun Build

If you are not interested in building a mash tun or just don’t have the time to put into it, here are some fantastic deals on mash tuns.

You can spend a lot of money on a mash tun to get all the features you would require to brew beer. However, you may just have an old cooler sitting in the basement that is collecting dust. You can also do a search on craiglist for “cooler” and locate one for $10 – $20.

The first thing you will want to investigate is the size of the cooler. For 5 gallons of beer you will want at least 10 gallons of space to mash in. These instructions use a 48 Quart Rubbermaid cooler. 12 Gallons will be more than enough room to mash. If you are looking for the size of a cooler simply get the part number from the bottom of the cooler and search for it in Bing or Google.

Note: Avoid any cooler that has wheels. Although the mobility is nice, the wheels are most likely designed to take away space from the inside of the cooler and could cause a stuck sparge.

The 48 Quart Rubbermaid cooler that we are going to use has been used as a mash tun for about 3 years. The copper ball valve and other parts have done great, but it is now time to upgrade to stainless steel.

There are two main items that you will need to purchase to make this build happen.

    1. Quick Fit Weldless 316 Stainless Steel Ball Valve with Bulkhead and 1/2 Inch Nipple

2. Quick Fit Weldless Bulkhead All thread with coupling.

You may not need the Quick Fit Weldless Bulkhead All thread with coupling. If the cooler wall is to thick then you will want it, so that you have threads on both the outer and inner cooler wall.

Let’s take a look at the parts:

You may not need all these, but more is better. The hole that exists in the cooler is ideal for 1/2″ size. All these parts are base 1/2′ diameter.

The first thing that needs to be considered is the existing seal in the cooler drain plug. When you remove the cooler drain plug you may think it won’t handle the heat or it won’t seal. However, the seal that came with the Rubbermaid cooler is ideal and has worked for 3 years. Therefore we will use it and slide it onto the all thread bulkhead.

Next, we will install the all thread bolt into the cooler hole.

Make sure you have enough threads on your outer wall an inner wall. (We missed taking a picture of the threads on the outer wall here but you should have the same amount as the inner wall shows)

Notice the existing seal that came with the cooler and the O ring that came with the Quick Fit Weldless 316 Stainless Steel Ball Valve with Bulkhead and 1/2 Inch Nipple

Here is the outer wall with the Ball Valve

The next step is to screw on the nut on the inner wall. Notice in the parts picture above that there is an insert or groove that allows the O-ring to sit right in there. This will allow you tighten the nut really good so there is no movement in your ball valve.

(…sorry for the fuzzy picture, but this gets the point across)

The next thing to consider is what kind of connector you want to use. You can use the existing coupling and threaded bolt. In this set we will use the adapter on the far right of the picture. I had it in my drawer of supplies so I thought it would be ideal to use in this build.

Here are both examples:

Now that our valve is installed.

We can start working on our false bottom.

If you prefer, you can purchase a 12″ Stainless Steel Bazooka Screen with 1/2″ MPT fitting.

In this posting we decided to go to our local hardware store and purchase a stainless steel braided hose for $5.

The first thing you will need to do is cut off the ends. You could use wire cutters or some metal scissors but having a Dremel is ideal for this situation. The vice in this picture, also makes cutting the hose very easy. Click here to get a vice for less than $25.

Here is what the hose looks like after the ends are cut off.

After the ends are cut off you will need to remove the inner tubing. You can use needle nose pliers to loosen each end from the outer braid. You want to keep the outer braid.

Once both ends are free the inner tube will come out with some massaging.

Here is a picture after the two are separated.

Ideally you will want a stainless steel plug to close off the other side of the false bottom.

Here we decided to use a stainless steel bolt.

We used tie wraps instead of clamps.

The next step is to attach the other end.

Here are both ends tie wrapped.

Now it is time to attached to the mash tun

That is it! Next is a water test. If the water test fails you may want to check your O-Rings and gaskets that are at the cooler wall.