Mash Tun Manfold How-To

Mash Tun Manifold

The final product, a completed copper manifold for use when batch sparging in a cooler mash tun

So, you’ve got a 10-gallon rubbermaid (or similar, generic) mash tun and stainless braid setup—most likely, you followed the excellent guide from Homebrewtalk.com—but you’re like me and are suffering through stuck sparges and you think the braid may be to blame.  While the braid is the typical batch sparge set-up championed by Denny Conn and works well for him and others, for some inexplicable reasons, it seems like the braid just doesn’t work for some people.  I speculate as to why, elsewhere; long story short, I tore out the braid from my mash tun and made my own copper pipe manifold.  I also increased it from 3/8″ to 1/2″ while I was at it.

I have had some excellent results with this manifold, immediately going from being frustrated with many stuck sparges, to smooth and steady lautering without rice hulls (even when milling at a gap less than 0.030″), enough so to recommend this approach.  Best of all, it requires only a small amount of know-how, and absolutely zero welding or other special knowledge.  This construction is entirely tension-fit, and as such, it’s also able to be disassembled after each brew session for easy cleaning!

Because this uses a 1/2″ ball valve instead of the 3/8″ ball valve from the HomeBrewTalk project, the parts list will be the same whether you are starting from scratch or converting your “braid” mash tun.  In addition to your 10-gallon rubbermaid cooler, you will need about $40 in parts:

All measurements are actual (or almost actual), not “nominal.”  Make sure you dry-fit everything at the store before you purchase it.  I tried to provide some examples from Home Depot, but parts, suppliers, and manufacturers change regularly.  Find a big-box hardware store with lots of loose parts—like Home Depot—and make sure everything threads up and otherwise fits together, just in case my measurements are off.  That said, the McMaster-Carr products are the exact ones I have.

Some notes on the parts list: the hose barb example (Watts #A-385) is best validated in-person, in the store, with a dry-fit.  The outer diameter (OD) of the barb is 1/2″, to accommodate 1/2″ tubing, and the NPT end will thread into the 1/2″ ball valve.

Stainless Washers

Note: These stainless washers have large-enough IDs to accommodate the pipe nipple, yet also have small-enough ODs to perfectly fit the groove on the spigot exterior.

Also, stainless steel washers are almost certainly impossible to find at any big-box hardware store.  I purchased a 10-pack of stainless washers for about $1/washer from McMaster-Carr, part number 98017A225, “300 Series Stainless Steel NAS 1149 Flat Washer, 7/8″ Size, 1.5″ OD, .082″-.098″ Thickness.”  They’re fantastic, and showed only two or three pinhole sized specks of corrosion after more than 20 mashes without any disassembly for cleaning.

Don’t short-change yourself on your washers!

You will also need:

  • A measuring tape;
  • Some C-clamps or similar, to hold the piping in place while cutting;
  • Teflon tape;
  • A jigsaw, hacksaw, or similar;
  • A metal file and/or sandpaper;
Copper Manifold

Manifold pieces, with slits cut, arranged in order.

Cut your 36″ copper pipe into six segments: one 9″ long, two 6″ long, two about 3 7/8″ long, and one about 1 1/4″ long.  You should be able to fit all of these segments together to form the manifold, and it should fit comfortably, perhaps snugly, inside the cooler.  The 9″ segment will be perpendicular to the ball valve, farthest from it; the 6″ segments will be parallel to the ball valve; the 3 7/8″ segments and the tee will be perpendicular to the ball valve, closest to it.

Leaving about 1″ buffer on either side, use your jigsaw or hacksaw to cut slits in all but the shortest (1 1/4″) sections.  Cut deep enough to reach half the diameter of the pipe.  I chose to cut using a blade that left a cut width of about 3/32″, and placed the center-line of my cuts about every 1/4″, to the best of my ability.  Remember, big(ger) openings are a-okay, as it’s the grain bed that does all the filtering, not your apparatus (be it manifold, braid, or false bottom)!

Ball Valve Parts

Parts for the ball valve portion, arranged in order from outside to inside.

Thoroughly de-burr all your cut segments.  Then, put all those cut segments aside, as well as all other pieces of the manifold, itself.

For the ball valve portion, assemble the following pieces in order, from end-to-end.  Be sure you also wrap all male-thread ends in teflon tape!  When assembling, you’re going to need to use quite a bit of elbow grease here to ensure that all pieces fit very tightly, including the pipe nipple; you may even need a small pipe wrench.

Ball Valve Inside

A close-up of the inside of the ball valve section, assembled parts 1 through 7.  Use the 1 1/4″ “joiner” segment to join the tee to this opening.

  1. Hose barb
  2. Ball Valve
  3. Stainless washer 1
  4. Stainless washer 2
  5. High-temp O-ring 1
  6. Pipe nippleInsert the assembled items, above, into the cooler spigot opening, and continue with #7.  The O-rings will be touching either side of the cooler spigot opening.
  7. High-temp O-ring 2
  8. Stainless Washer 3
  9. Stainless Washer 4
  10. Stainless Washer 5
  11. Female NPT-Compression Adapter
Mash Tun Manifold, Inserted

The mash tun manifold, assembled and inserted in-place. With the cooler diameter only slightly larger, it stays assembled easily without any welding, glue, or anything else.

Once you have the ball-valve securely in-place, you should now be able to use the 1 1/4″ segment as the “joiner” between the tee and the female NPT-compression adapter (my “joiner” fit so securely I could never easily remove it, but no big deal there).  Use the tee as the pivot point for your assembled manifold, and push it into place, slits down, of course.

You’re done!  Test for leaks with some hot water, and it’s ready to brew!

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