Mash tun design queries

[Liam Callaghan]

Hey guys,

I had an interesting meeting with the fabricators regards making mash tuns and the options available to me and rough order of costs. 

There are a few design options and sizes and I just wanted to put them out there for some feedback before I make a decision on whether to proceed with it.

We are looking at cylindrical tanks with a shaped bottom, minimum false bottom space and 1' outlet with either a screen or pick up pipe.

Sizes are in litres from the top of the tank to the screen:-

28.8

47.3

67.7

False bottom will be approx. 1.8 litres with 25mm depth depending on outlet pipe size.

1" Outlet at the bottom, possible 1' inlet near the top for sparge water in. 

There are two options for the materials one rigid and good with high temps but very brittle and easy to crack, the other is the same as the fermentors and rugged as, but this doesn't take high temperatur (ok to 80 degrees or so without deformation).

Construction options are thick single skin with possible thermal jacket if needed and dual skin.  Dual skin options are with a rigid foam infill or just an air gap.  At this stage the less brittle plastic is preferable but this will need the foam to make rigid under temperature if a dual skinned option is chosen.

Screen in perforated plastic or stainless?  Both?

Pick up pipe in copper pipe and push fit to outlet so you can remove for cleaning

 

Basic costs would be around $120 for the single skin and $230 for the dual skin.

 

Lids would be the same as the fermentors so interchangable, hopefully help to keep peoples costs down and keep things affordable. 

Personally I think the single skin would be more cost effective so long as it holds to within 2 degrees over 90 minutes.  I'll test it this week.

I'd really like to be able to get these out onto the market at the same time as the conicals if I can but a big if at the minute, but 6 to 8 weeks is what we are aiming for.  If anyone has any feedback, suggestions or otherwise it would be gratefully recieved.

Especially regards cost and what people are already using.  I use a cool bin atm and I'm on my thrid on e in 10 years.  Cheap and pretty good as long you handle them properly.  Can mash upto 65 litres in it but its a snug fit :p

 

Liam

[Hugh Grierson]

Hey Liam.

I used a 40L chilly bin for a bit but never really got good efficiency, so I then made a Lauter Tun (I mash in the kettle), out of my mums old agitator washing machine bowl. Its dimensions are 3500mm by 6000. See it here http://www.forum.realbeer.co.nz/forum/topics/mash-tun-out-of-old-ag....

Anyway, it has a similar ratio of depth to width as commercial set ups I have seen, and is fantastically efficient, I had to reduce my grain bill as my beers were silly on the alc.

I would use a single skin, my one has a layer of bed roll on it, and keeps the heat really well, so you could make the insulation DIY and keep the cost down.

 

[Grant R Baker]

When I last made a mashtun from a chilliy bin I hunted around for one with a drainage channel in the bottom. Thus my SS braided hose sits (mostly) within the drainage channel providing very little deadspace. I can seend a photo of my last build if ya want.

The drainage channel also gets deerper is it proceeds to the drainage plug. I recommend looking at a Coleman Xtreme 34l esky for an example... but here is a quick drawing of what I mean.

 

[Paul Fraser]

Hi Liam. You state the basic setup price would be $120 for a single skin and $230 for the dual skin. What size tun would those prices be for? I think for me the 28.8L would be fine but if i was going to buy one i think i would buy the 47.3L one for the possibility of doing bigger mashes in the future.

 

I like what you're doing here Liam and will keep an eye on your progress. Cheers

[Ralph]

I would be heading for a 67L one as I am finding my 40L chilly bin not big enough!!

It would be easy enough to add insulation from closed cell foam, but I really like the idea of dual skin beast.

Options are sounding good. I would probably go for a SS false bottom if possible. 

Having said all that I think ultimately I would like a full SS mash tun... and may end up going towards building myself one at some stage.

[Liam Callaghan]

Thanks for that guy, defnitely some food for thought.  I like the wider mash tun with more spread out grain rather than a deep grain bed.  I don't know enought about the mechanics of if to make a good decision on that so will have to hit up the pro's and see what they think. 

How do you find the drain being at the bottom Hugh?  Makes some sense for me to follow this as it reduces deadspace but not sure about keeping unwanted solids out. 

Even with the 70 litre option we are only looking a 640mm cylinder height and that would be filled to about 450 for 10kg of grain.  Again, just need to ask and run a quick experiment with it.

Thanks Paul, price is just a ball part figure for the middle one, just a semi educated guess at this stage.

We did a quick sample design of the base yesterday Grant, shaped with a lip around the base to support a screen and outlet under that.  If I make the feet taller I could easily shape the base with a groove and outlet from the bottom.  Was also looking at running the outlet above the screen and piped through it.  I can reduce the deadspace dramatically doing that.

I'll post some pdf's later.

You have stainless steel fever Ralph haha!  I'd prefer a dual skin as well but the cost and manufacture is prohibative, much more cost effective refitting existing cool bins I reckon.  They have a pretty good life span.

Guy, the mash tuns will be super durable.  Wait until you get your hands on a conical then you'll understand.  Never seen a tank made that you can hand down from generation to generation :p

Thinking about that its probably not good for long term business lol

[Grant R Baker]

Yep the only problem I see with a drainage channel and braid hose is that it could get crushed under heavy/larger loads.

It works for me in my 34l mashtun but larger brew mean more weight.. so the false bottom idea would be better there.

[Liam Callaghan]

Hey Grant,

Yeah the braid would tank some pressure in the bigger MT unless I make it wider at the base, very tempted on this but might have to wait a few months for that if I do.  Having the option though is key I think, so people can run it how they want and change it without having to buy a new unit.

Only ever tried the braided hose when I started and it didn't work so I've used a manifold since.  I make a real nice screen for the bottom of my cool bin too and struggled to get it to run clear because of the deadspace, bit hard t tell as I was getting some poorly milled grain at the time so too many variables.

The manifolds are great from my experience, bulletproof.  The screen should be the same and clear for stirring which is a bonus.  Will still depend on the milled grain quality though I guess.

We'll make a false bottom with it anyway but I'd like to accommodate all budgets like with the conicals.  People can buy what they need and make what they can to keep costs down and if your like me enjoy making the other parts.

Interestingly it seems a lot of people prefer are keen to have the tanks ready to use off the shelf.  Mike and Bryan warned me of this but I am still surprised.  I'd have expected more tinkerers, happy to get a cheap tank and build it into their systems.  Will work out very cost effective for the people that like to/can tinker.  

[Grant R Baker]

hmm I'm not too surprised. In this day many just buy of the self and if it isn't right they just buy something else.

 

I enjoyed my little job of ferreting around and finding the right chilly bin, fittings, ball valve, converting a washing machine SS braid hose into a sieve and fitting it all together (beats my day job)... but others don't.

I would have looked at coverting a feeder or grain bin into a conical one day... but I think your design kicks that idea away (just as well)...

[Liam Callaghan]

I wouldn't let that hold you back mate, I wont be making a 1000 litre option and you'll need that for the new brewery your going to build... :p

Same I enjoy the building and designing bit but very happy to make them off the shelf, just need a good source of stainless and plastic fittings now.  Unfotunately they don't get made here so we're at the mercy of importers and distributors

[Liam Callaghan]

Flicked both of these options in to be priced for the bottoms of the mash tuns.