So Yeah, Dood…

In the last installment of “How do I do that?” I described what’s happening chemically during the mash.

This time I need to tell you how to build a mash tun, but that will also require me briefly describing the ways in which you can sparge your mash. Spargeing is just rinsing the grain bed to remove sugars that have been left behind from the mash runoff. This step actually comes after the mash, which seems a bit like putting the cart before the horse.

Why would that matter?  Because how you sparge will have a large effect on how you build your tun.

• If you intend to fly sparge — i.e. slowly drizzle water over the top of the grain bed to rinse the grain — you will probably want to build a manifold for your filter.
• If you intend to batch sparge — i.e. drain all of your initial mash liquid and then add your sparge water to rinse the grain — you can save money by building a tun with a stainless steel braid for your filter.

Building a manifold will not negatively affect your results if you batch sparge — in fact I’ve heard reports that it will increase your efficiency greatly — but you shouldn’t fly sparge with a stainless braid filter. More on that later on.

So… since we know what the mash is, we can start talking about how to build a mash tun and why we choose the parts we do for one.

It’s best to use a vessel for the mash tun that will maintain a relatively static internal temperature. It needs to be insulated, and since we’re going to be modifying it a bit, it should be relatively cheap.

The answer most homebrewers come up with in terms of mash tuns is a cooler of some type. I use a 17.5  gallon Igloo Cube cooler. It’s convenient for a number of reasons. It retains heat in the grain bed very well because there is less exposed surface area than in rectangular coolers, it is easily modified for either stainless braid or manifold filtration — and cheaper to modify for manifold because of the smaller, square bottom. But in reality, any cooler that has a removable drain spigot will do, round, rectangular, etc.

You’ll also need to make a decision in terms of fittings. Do you want to spend the money on stainless steel? Save some money by using brass? Or really go thrifty and use all PVC? I prefer stainless, but you can go brass too. My fittings are actually mixed and matched here and there — stainless valves and braid, but a lot of brass joints.

Yes, I presently batch sparge with stainless braid, but I’m interested in converting to a manifold for fly sparging. That said, when I build it, I’ll probably end up filming the process so you can see exactly how it’s done.

The next thing you’ll need is a ball valve to replace that drain spigot. For the cube cooler, I use a ½” ball valve conversion kit purchased at the Thirsty Brewer. This particular setup also includes all the fittings to ensure a proper seal. It adds the valve and threaded inner bulkhead to the cooler that you’ll need to put in your filtration system.

What you do next depends on how you want to sparge:

• If you’re taking the batch sparge path, stainless steel braid route — which is cheaper and easier, but more limiting in terms of how you sparge — you’ll go buy a length of stainless sheathed plumbing hose — think toilet hose. Cut off the ends of the hose, and compress the braid the way you would a Chinese finger trap. Buy a brass or stainless t-joint fitting that will fit into your threaded bulkhead, and some stainless screw clamps. Clamp the ends of your braid over the t-joint and you’re finished. There’s no need for sparge arms, or drip tubes, so you’re essentially done.
• If you’re going the manifold route, you’ve got a number of options in terms of design; you can use as many twists and turns as you can imagine, and thus as many copper or food grade PVC joints as your checkbook will allow. Just remember that you’ll have to clean this thing too, as such I don’t recommend soldering, or permanently gluing the joints. Threads would be nice but would up the price. I’m not going to go into too much detail in terms of design, use your imagination, and common sense, the above pic should help too. Essentially, you’ll want to run copper tubing or PVC pipe either around the edges of the bottom of the tun, or have pipe laid down the middle with t-joints branching out from the center. The tubing should have holes drilled in it, or slits cut in it so your mash liquid can drain through them to your kettle. The slots or holes on the manifold will work better if they’re cut into the side of your pipes, rather than the bottom. The tubing will connect to your ball valve through the threaded bulkhead.

Fly sparging will also require a system that will allow you to slowly apply more water to the grain bed once you’ve completed your initial runoff. This can be either fully integrated into the tun, or removable — I would suggest removable; easier to clean, easier to fix if something goes wrong.

For this, you’ll need some PVC piping, a couple of joints and a valve that will allow you to control the flow rate of the sparge water you are applying to your grain bed. You’ll also need either a pump — which will be another post entirely — or you’ll need to elevate your hot liquor tank —  i.e. the vessel in which you have heated water, or are storing heated water — to a level at which gravity will feed water to your sparge arm.

Tags: Lauter Tun, Mash Tun, Mashing, Sparge Arm

This entry was posted on Thursday, February 25th, 2010 at 1:33 pm and is filed under Beer, Brewing, Geek-Out. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.