Mash Tuns for Home Brewers

There are various set-ups used by home brewers to mash their grains.  The main criteria are:

• Good insulation to maintain the temperature of the goods for up to 1 1/2 hours
• A reliable filter to allow the sweet wort to be run off when the mash is complete

Types of Mash Tun
A popular design is the picnic cooler mash tun which takes advantage of the thermal insulation around a cheap plastic picnic box. The box is fitted with a standard barrel tap and the filter is usually made from lengths of 22mm copper pipe with saw cuts placed at regular intervals to allow the wort to drain out. My favourite design, though, is the 'false bottom' mash tun using a standard plastic brewing bucket. The design below was inspired by a guy who went by the name of Daab on my forum; his design used a plastic plate for the filter, but I've improved it by using a stainless steel hob cover that I picked up in a market for a few quid. The false bottom tun, I find, drains far more reliably than a picnic cooler type resulting in fewer stuck mashes.

Insulation
The first task is to insulate your bucket (which must be fitted with a drum tap). I actually used a home brew boiler. A good, cheap  form of insulation is camping mats which can be bought from outdoor shops. If you keep your eyes open, you might even get one for next to nothing in a supermarket at certain times of the year.

Just cut the mat to suit and wrap it round the plastic bucket, fixing it with duct tape or similar.

Making Your False Bottom

Start with a stainless steel hob cover (or similar)....

You will also need a tank connector (available from plumbing suppliers), a 15mm elbow connector, a couple of short lengths of 15mm copper pipe and some plastic tubing that will be a tight fit on the copper pipe. You will also need appropriate sized drills.

Next step is to drill a central hole and fit the tank connector...

The underside looks like this....

Next step is to cut the top of the tank connector off to leave the fitting flush with the top of the nut.....

The next bit is the real pain - you need to drill as many 2mm holes as you can, spread evenly over the SS dish. My advice is to buy a pack of cheap 2mm drills - you will break a lot of them drilling stainless steel even if you're careful....

Fit 2 short lengths of 15mm pipe into each end of a 90 degree elbow, then feed one end into the tank connector....

The whole assembly is placed at the bottom of the brewing bucket and connected to the tap with a piece of plastic tubing...

Because I used an old boiler, there's an element stuck in there; it's handy for clamping the filter down, but isn't essential of course.

The flow rate from this mash tun is excellent and I have yet to have a stuck mash with it.