Mash Tun Design Series: Sparging and Lautering (part 2)

We’re continuing our series on mash tun design this week.  Last week, John gave us an in-depth look at the container you use for your mash tun.  Once you have selected a container, you will need to outfit it to enable you to rinse your grain, so this week John will introduce us to the sparging process and discuss the different options for draining the sweet wort from your mash tun, and next week we’ll discuss the pros and cons of batch sparging, fly sparging and the no-sparge method.

What is a Sparging?

Well, after mashing, you’ve just spent a lot of time and energy converting starchy grain into sugary wet grain. Sparging is the process of rinsing the sugar from the grain bed. Professional brewers will often refer to this as Lautering, the terms are interchangeable. You won’t however, hear of a “sparge tun,” but many breweries do have a separate Lauter Tun.


Many professional brewers and brewerys employ a separate lauter tun. That is, the mash is done in a temperature controlled vessel then pumped to a separate vessel where the grain is lautered (sparged) to pull out the sugar-water. We, as homebrewers, tend to want to make things as simple as possible. So we’d like to combine the mash and lauter tuns to a single vessel.

Thus, now we have another consideration when thinking about mash tun design. If we’re going to lauter in the same vessel (i.e. pouring water in the top to rinse the grain), we need to have a way to get the sugar-water (runnings) out again. Typically this involves installing a port (i.e. a hole) near the bottom of whatever vessel we’re using. We better put a valve on the port so we can control how much comes out.

If this were all we needed, life would be good. Unfortunately, if you leave a hole at the bottom of your tun, it quickly plugs up with grain – one way to get a “stuck sparge.” To combat this problem, the industry has developed a whole host of neat little gadgets to help you screen out the grain while letting the water pass through.

There are several ways to keep the grain from compacting into whatever port you’re using to drain the water out. Most involve some sort of screen, where the holes are small enough to keep most of the grain in, but big enough to let most of the water out.

Types of Screens

Grain Bag

brew in a bagFirst, the simplest, is a large grain bag. Most homebrewers started brewing on their stovetops with extract. Then moved up to extract with specialty grains. Some used a colander to steep the grains, others (whose significant others were already mad at how much cooking equipment we were using) used a grain bag to steep the grains in before bring the water to a boil. Well, the same idea can be used for sparging. If you get a large grain bag, you can line your mash tun with it, and it will generally keep the grain from plugging your outlet port.

The downside is that grain bags, in my experience, tend to encourage “channeling.” Channeling is how the water, which wants to take the path of least resistance, bypasses the grain bed and goes down the sides of the mash tun and out the bottom. Or, takes a particular path through the grain bed and doesn’t get to rinse all the grain – you end up with pockets of sugary grain still left at the end of the sparge, sugar that should have been in your wort.

The other issue with bags is that they only come in a few sizes and aren’t fun to clean. I’ve never made a 10 gal batch using a grain bag as a sparge screen, but the few 5 gal batches I’ve made make me wonder if I could get a bag big enough. That said, the Brew-In-A-Bag method uses grain bags for this very thing and seems to work out really well for a lot of people – but that’s essentially a no-sparge method (more on this later).


manifoldMany homebrewers use a manifold system in their mash tun. These are inexpensive to build or buy and can be made out of almost any material (copper, PVC, etc.). Just be sure that, if you build one, the materials you use are food grade.

Manifolds are rugged and reliable. The design often depends on the shape of the tun and the flow rates you’re looking for. The key to this is to have the manifold holes/slots small enough to keep out the grain (so the manifold doesn’t plug) and to have enough of them to allow a significant amount of wort to be collected (sufficient flow rate).

I haven’t used a manifold system, but those I know who have swear by them.  They can be an ideal choice for square/rectangle mash tuns.  For me (with a round mash tun), I was looking for something a little more elegant. Also, depending on how you build/design your manifold, it can be a real pain to clean or unclog.

False Bottom

false bottomA popular option, and the one most professional brewers use, is a false bottom. This typically involves a plastic or metal screen or perforated material that holds the grain bed above the outlet of the tun. Using something like this ensures the best chance that the water travels smoothly across the entire grain bed (without channeling) and reduces the chance of the grain or grain bed clogging the outlet.

False bottoms, in my opinion, are one of the best technologies available, if done right. I’ve used home-made falsebottoms (do you know how many hundreds of holes you have to drill?!? With a 1/16th in drill bit!) with mixed results. Overall the flow rates were really good and the grain bed held up well. But – and there’s always a “but” – false bottoms, if not fitted really well, can be disturbed pretty easily if you stir your mash. I made a plastic false bottom once and within the first 10 min of the mash I felt it shift and the top of the grain bed move down about a ½ inch – so much for a reasonably quick sparge! My grain had just slid under the false bottom and come to rest right up against (and in) my outlet valve.

However, there are some truly fine products out there to match almost any mash tun design and provide a good fit. Also, because of the amount of work to create a false bottom, they tend to be expensive (at least for my meager budget) relative to some of the other gadgets we’ll talk about.

Tube Screen

bazooka screenThis style is essentially a stainless (or other material) screen sewn together in the shape of a tube and fitted to coupling (so you can install it in your tun). These styles are relatively inexpensive and easy to clean, the down side is that it doesn’t collect as evenly across the bottom of the grain bed, so you do have to be careful of channeling (I’ll tell you how to avoid this later).

Personally, I use a tube screen and have been really happy with it. I paid about $20 for mine and I’ve been using it for at least 6 years. I really like this option, I don’t want to name names, but let’s just say that the one I use rhymes with “Paducah bean.”

Braided Stainless Steel – the Ghetto Tube Screen

I was really impressed when I heard about this one. What a great idea! There are a couple of websites that tell you how to do this, but the idea is that you:

  1. Buy a braided stainless steel hose (for a sink or toilet)
  2. Remove the hose lining
  3. Crimp one end of the braided steel tube
  4. Tadaa! A variable length screen (much like the Tube Screen) that you can install in your tun!

Of course I had to try one. I made one, but I have to say, I wasn’t all that impressed. I know individuals who get really good results from this, and the right weave of the braid gives really clear wort from the first runnings. My issue with it was that I couldn’t get the flow rate I wanted out of it. It works fine if you’re gravity draining the tun, but if you want to recirculate your wort (with a pump), it’s probably less than ideal. You also have to worry about the weight of the grain bed crushing the tube and making it, more or less, useless – again, there are several websites that talk about ways to avoid this.


My vote is to go with something like a tube screen or false bottom. These are the most robust and least troublesome options. They clean easily, will hold up for a good long time (with proper care), and perform well – in my experience. But – and there’s always a “but” – before you decide which way to go, think about the next decision -> how will you sparge? We’ll cover the pros and cons of batch sparging and fly sparging next week.

Mash Tun Design Series: Equipment (part 1)
Mash Tun Design Series: Batch vs Fly Sparging (part 3)
Mash Tun Design Series: Temperature Control (part 4)



Another GREAT article man. Keep them coming!

Jay Biddle

Thanks for your excellent clues. I am a addicted home brewer always looking for another tool.

Suggestion: A friend suggested I wrap my copper manifold in a grain bag as I set up the mash tun.
Result: My first runnings are always clear and I never get clogged up….

Sounds like a toast

Cheers, Jay


Hi Jay – glad you enjoyed the article. And that is an excellent suggestion – thanks for sharing! The only downside I can think of immediately would be that it’s one more thing to clean.

You should be able to get clear runnings without the grain bag as long as you verlof a few quarts to let the grain bed settle. By taking the first few quarts and adding them back to the top, you allow the grain bed to settle into a filter around your mainfold, and from that point on, you should be getting pretty clear runnings.


Hi, You said that many professional brewers and brewerys employ a separate lauter tun and mash tun. What pump used to do it?

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