Mash tun design question

[Magnew]

I am getting ready to make the leap from mini-mash to all grain. I am currently looking at building a cooler mash tun. I have heard that you get better efficiency with a shallow grain bed, which would suggest a rectangular cooler. I know some people use these, but most seem to go with the upright orange cooler. Why is that? Could someone talk about the relative benefits of both designs?

[Mad Scientist]

Don't worry mini-mash to all grain is a step, not a leap.

I usually have great results fly sparging with a ten gallon round cooler, but I seem to be rushing my steps lately (at mash out). this allows me to have a shallow grain bed, ~5 inches, for normal gravity-type ales, but it also has the capacity for large amounts of grain--I have yet to fill it up completley. What might concern me about a rectangular or square cooler is the increased surface area (and shallower grain bed depth)--you'd have to batch sparge only, you would not be albee to fly sparge, and even them your wort may not clear.

Unless you are planning to make ten gallon batches(i.e. lots of grain every brew), a square or rectangle cooler may not be for you. So obviously my vote goes for a round cooler, but let us see what the rest of the board has to say.

Palmer (www.howtobrew.com) has an excellent dicussion on mash/lauter tun desgn. Check it out, if you have not done so.

I think something else that comes into play with thisdiscussion is: manifold or flase bottom? which is best?

[Vienna Lager]

Mag, B Brew gave good advice and make sure you follow up with Palmer's 'How to Brew'. There are pros and cons to round vs rectangular tun design and it seems to come down to how much $ you what to spend or time you have to scrounge around and put together a mash/lauter tun.

B Brew has good results with a round tun design and I seem to have good result with a rectangular design.

In prior threads, can't remember which one(s) I mentioned my tun design so will explain what I did. I rescued a 50+ qt thermos rectangular cooler that had broken plastic hinges and was destine for my son's sand box or curb side on garbage day. The drain hole was all bunged up so sealed it with expando foam. I made a copper manifold based on the geometry out lined ny Palmer and run a siphon tube over the side wall. I do 5 gallon batches and my grain bed can be 4-6 " depending on my grain bill and I do a combo batch- fly sparge. I batch in 3-4 gallons of sparge water then about 2 gallons fly sparge. I take a 3 liter Kool aid pitcher and dip it into my HLT filling it about 3/4 full then with SS lid in my left hand hold it at about a 45 degree angle over the tun. In my right hand is the pitcher and I slowly pour the sparge water onto the lid which spreads out in a fan shape. Both hands then move in unison to make sure the entire surface of the grain bed is reached by the fan shape. I hit target S.G.s of 1.050 to 1.058 depending on my grain bill. The stuff I used to make my tun was "A&A" Avaliable and Affordable.

[danno]

Michael, I've got a 5 gallon Rubbermaid cooler (round one) that I don't use, and I be willing to let go cheap... PM me if you're interested...

[Vienna Lager]

Mag, I think you should go with the round design because it is "A&A".

[Magnew]

Thanks for all the advice. What's "A&A"?

As for the rectangular design I'm thinking about, it will allow for fly sparging. Has a sparge sprinkler system built into the lid.

http://homebrew.com/articles/article09130301.shtml

[Vienna Lager]

"A&A" = Avaliable & Affordable.

[brewmonkey]

For homebrewing 12-18" is about the maximum depth you want to go. However sometimes it is not easy to find that so you can go with the 5gal Gott's.

The reason you want a thinner bed is that it allows for a better runoff. Too deep and you will see a reduction in the efficiency of the system as well you have a better chance of either setting the bed or creating channels during lauter.

[SV650TN]

Greg Noonan actually gives 12" as a minimum grain bed depth with 2-row varieties, 6" for 6-row. I personally get about 6 percentage points higher (85%) when I use my bottling bucket with a manifold, than when I use my rectangular cooler as a lauter tun. I think the greater your bed depth, the more uniform the sparge, but the greater risk of a stuck/set mash.

I've switched to simply mashing in my old cooler, and using my cylindrical lauter tun with a copper manifold, unless I'm using a lot of grain for a big beer.

[haaseg]

I like the round cooler with the false bottom. I haven't flipped through my copy of Palmer in a while, but I seem to remember the diagram where he shows how the water channels through the grain and out the manifold. With a good false bottom in a round cooler, you get almost uniform flow throughout the entire grainbed. The argument against the rectangular coolers is that you don't get quite as good a rinse on the grains in the corners because the water has farther to travel before it hits the manifold. When the water doesn't flow consistently across the grainbed, it starts to channel in places where it's moving faster.

I've seen a lot of people come up with some crazy ways to build manifolds, etc, for their cooler/mash tuns. IMHO, it's worth it to just spend the $25 for a good stainless false bottom for the round cooler.

I just bought the all grain kit, which comes with 2x 5 gallon coolers, sparge arm, false bottom, ball valves, and tubing. I priced out all the components separately, and I figured I'd save a couple of bucks - to me it wasn't worth the hassle. Just pick up the phone and order - and a few days later everything comes all at once and you spend a couple of minutes putting it all together.

[Trogger]

I use a plastic bottling bucket with a false bottom. At higher amounts of grain, I do have a slow, and once in a while stuck sparge issue. However, in general, I like the round design. I’ve gotten 80+% efficiency on a couple of batches. I fly sparge.

[MikShau]

I went with the A&A approach, old rectangular cooler in the garage, left over piece of CPVC and came up with something that looked like your link. except my cooler had broken hinges and it's red. I know it's macho to talk efficiency but at <$1 / pound and the fact that the best beer comes from the first runnings, I'm happy with the 70 - 78% I get.

Do what makes you happy.

[SV650TN]

Inefficiency in and of itself is not an issue. But it can be a symptom of a problem, namely that you are undersparging portions of your mash, and oversparging other portions which can lead to tannin extraction. This will be exacerbated with shallower grain-bed depths/low gravity beers. I found a mellowing effect once my efficiency increased, and it was entirely due to an improper manifold design.

So if you are getting a uniform, but incomplete, rinse of the grains then yes who cares about efficiency. But that may not be what is happening. You may be leaving a good portion of the "good first runnings" behind, and extracting tannins to boot.

[takhsh]

Originally posted by SV650TN

I found a mellowing effect once my efficiency increased, and it was entirely due to an improper manifold design.

This is very intersting. Also it is very believable. Could you give us more information about the two manifold designs?

You may be leaving a good portion of the "good first runnings" behind, and extracting tannins to boot.

On this note though, I think that it may be far stretched out since tannins contribute nothing to gravity. Before one start exracting tannins the sugars also would get diluted. A diluted sugar extract contributes little to gravity too. Although this may happen, it would take a really bad design, and this is the reason I like to hear from you what was the maniford design that produced non-mellow beer. We may have this bad design, and naturally we like to go away form it!

takhsh

[SV650TN]

I have a 4 pipe manifold in a 52 quart cooler. The two "outside" pipes were directly against the wall of the cooler, which must have created channeling down the sides. So essentially the two inside pipes were the only ones doing much extracting. With 10 gallon batches and 5 gallon batches with gravities over 1.050, this wasn't a problem (John Palmer's How to Brew illustrates this well), but anything under 1.050 and the beers started to get an astringency that only could come from oversparging. My efficiency was only around 65-70 percent, sometimes lower, so I think that portions of the mash were oversparged (those areas directly over the pipe) with shallow grain beds and the areas to the sides were undersparged.

I cut down the manifold to create 2" of space between the cooler side and the outside pipes, and efficiency jumped 8-9%. I haven't brewed a low-gravity beer with it yet, as I have recently made a new manifold for use in my bottling bucket for low-gravity beers. My efficiency with that setup is getting consistent 85%, and vorlauf takes no time at all, and the runoff is very, very clear and particle-free. I prefer the deeper grain bed. And the low-gravity beers are (so far) free of any astringency.