Mash Tun Manifold

If you're thinking of making the switch from malt extract brewing to all-grain brewing, you might be a little intimidated by all of the equipment and options. Most folks end up going with a rectangular cooler as a mash/lauter tun because of cost, availability, and excellent performance. If you decide to go this way as well, you'll need some way to get the good stuff (wort) out of the grain.

There are several methods to separate the sweet wort from grain bed in your mash tun, including using a false bottom or a stainless steel braided hose (commercially available for brewing under the name Bazooka Screen, or as a DIY project using braided water supply line). Homebrew great and batch sparging pioneer Denny Conn has a great tutorial on making a simple braided hose-based mash tun at www.hbd.org/cascade/dennybrew/.

Another great option is to use a manifold, which is an array of perforated piping that sits at the bottom of the mash tun and allows the wort to runoff while leaving the grains behind. You can use either hard copper pipe and fittings or CPVC, but for general sturdiness and long-term stability, I highly recommend copper. Despite the skyrocketing cost of copper over the past few years, you make a copper sparging manifold for about $15. And because there isn’t significant pressure put on the pipes (like in a home or industrial water distribution system), there is no need to solder the joints together. You can have a new manifold with about an hour of construction time. And since it isn’t soldered together, it can easily be broken down for cleaning and storage after each use.

PARTS (Fig. 1)
* Approximately 5 feet of 1/2-inch hard copper pipe (type M or type L)
* (4) 1/2-inch 90-degree copper elbow fittings
* (3) 1/2-inch “T” copper fittings
* (1) 1/2-inch 45-degree copper street elbow fitting
* (1) 1/2-inch copper male pipe thread adapter

FIG 1:

Cutting the copper pipe is fairly straightforward. A common hacksaw is probably the best tool for the job, although you can also use a rotary tool with large metal cutoff wheels (Dremel part number EZ456) with satisfactory results.

The idea is to run the pipe around all areas of the mash tun to minimize “dead spots” (from which wort is difficult or impossible to collect), and also to reduce “channeling” of the grain. Channeling is mostly an issue in fly (continuous) sparging since in batch sparging the grain is stirred, but pulling the wort from all areas of the mash tun simultaneously is never a bad thing. And a manifold is ideal if you want to fly sparge in a square mash tun (like an Igloo IceCube cooler, for example) where a false bottom will not work.

It is important that the manifold sit flush with the bottom of the tun. This is so that as much wort as possible is recovered from the mash tun and also so that you won’t hit it with your mash paddle while stirring the grain.

The 45-degree street elbow in the parts list above will not be required for all mash tuns. Mine is based on a Coleman Xtreme 52-qt cooler and it has a depressed trough leading up to the output valve. The 45-degree elbow, along with a short piece of copper pipe and attached to one of the “T” fittings, was just the right angle, length, and height to elevate the manifold above the trough level and make it flush with the bottom of the cooler. Attach this to the 1/2-inch male pipe thread adapter and screw that into the bulkhead fitting on your mash tun (Fig. 2).

FIG 2:

Now you can begin measuring and fitting the sections of pipe and fittings. Start from the first “T” fitting and work your way towards the opposite end of the cooler (Fig. 3).

FIG 3:

For effective lautering, the manifold should be more than just a ring around the inner edges of the mash tun. You should include at least one section of pipe across the center of the tun (Fig. 4). How many cross pieces you include is up to you, but more than two probably won’t yield any performance improvements. For each cross piece, you’ll need another section of pipe and two “T” fittings.

FIG 4:

On each section of pipe (the straight pieces, not the elbows and other fittings), you should make a cut with the saw about every half inch (Fig. 5). You can space the cuts closer together than this if you prefer, but it’s not necessary to do so, and I don’t recommend going any closer together than quarter-inch spacing. Each cut should be no deeper than a little less than halfway through the pipe.

FIG 5:

Once all the cuts are made, wash all of the pipe sections and fittings in a mild detergent solution. Now reassemble the manifold and it’s ready for your next all-grain brew session. If you find that any of the joints don’t fit snugly, or that they loosen over time and repeated use, you can manually crimp the loose fittings with pliers to tighten them up.

Now you're ready for all-grain brewing and some delicious homebrewed beer!