[toddster]

I'm getting ready to fab up a 3 bbl system and trying to decide how big to make the mash tun. My thoughts are make it large enough for a high gravity beer. What do you pros think?  Todd

[morticaixavier]

so you want a tun large enough to accomodate ~150 lbs of grain and ~55-75 gallons of water

scaling up from my home sized rig which is 72 qt capacity and can just barely handle 30 lbs grain with ~12 gallons water you need 5 times as much, maybe a little more, around 90 gallons capacity. this should allow you to make all the way up to 1.100 with ease. and pushing it maybe 1.110.

Some pros who lack the capacity to do high gravity due to MT size double mash. mash half the grain, drain, bring the wort back up to strike temp, refill the tun with the other half of the grain and mash using the previously mashed wort as hot liquor.

[tschmidlin]

I would go bigger than 3 bbls, probably more like 5 bbls.  You want to be able to mix it easily and have plenty of room.  I think morticai's number is fine, but if you are building it I think the cost to make it bigger now will be incremental compared to the cost of building it in the first place.

[morticaixavier]

I agree with Tom. I would say 90 gallon is a minimum and as long as you are doing it the cost difference will be minimal to make it a 100-150 gallon.

[a10t2]

Are you going to be doing any multi-rest mashes? If so, is the tun jacketed, or will you need room for infusions?

[Gribble]

I'm in the process of getting my 3bbl brewhouse built to 150 gallons.  Dimensions 46" diameter, 28" tall, 2" drop conical bottom with the pick up in the center.  The fabricator I'm working with trades work for beer so I'm paying for material cost and welding consumables, all the fab work at 1/2 bbl a month for a year.  Works for me.

[toddster]

Well I don't want it too large that the mash depth is going to be not very deep. I was thinking of 36" in diameter and 36" high with a slight tapered floor. This would be a pox 5 bbl in liquid volume.
Where I'm having trouble is figuring the volume of liquid and grains.

I was planning on insulating it and maybe doing a jacket that can use hot water to bring the temp up. Other wise I could do a herms set up pretty easy.

[boulderbrewer]

You will gain almost double volume by going to 4' in diameter. just saying.

[Gribble]

Would having the mash tun wider than it is deep have any advantages.  What would be the optimum mash tun design.

[boulderbrewer]

Would having the mash tun wider than it is deep have any advantages.  What would be the optimum mash tun design.

at 3x3 why not 4x4 and double your volume or 5x5. A mash tun that is easy to clean out is the best. Yes it would be nice to be able to fire a tun directly but not a necessity.

I'm of the code go big or go home, what would a 3x3 (85 cuft) cost compared to a 5x5 (400 cuft) just saying.

[Gribble]

The cost of going up that extra foot in diameter is miniscule.  Yeah there is a little bit more metal and fabrication involved, but it's so small that it would be most cost effective to start with a 5 or 7 bbl system.

[dean]

You could just pick up a livestock watering tank, the price is right comparatively speaking.  Plastic or steel... either way, if it isn't what you want you aren't out much. 

[Thirsty_Monk]

Would having the mash tun wider than it is deep have any advantages.  What would be the optimum mash tun design.

Better lautering.

To my experience no need to have insulated MLT.
The volume vs surface area is pretty small and it keeps the temp pretty good.
My MLT is 3" by 4".
Any larger one and you need to have rakes to mix the mash or to have catwalk all around the MLT. 

I think 1 X 1 is your optimal design.

[toddster]

Thanks for the input.
My mash tun will be  just under 36" diameter and 36" tall. The liquid volume will be 159 gallons.
It will have a slight cone shaped bottom with a false bottom 3 inches off the highest point.
I will insulate it with one inch of rock wool and that should hold the temp constant for 90 minutes.
I will have a 1-1/2' long sweep 90 that will be at the center of the cone.
Once the prototype is build and tested I will post photo's. I ordered the stainless last week for the prototype and my new welder is sitting waiting for it. 

[Thirsty_Monk]

Looking Good.

Just make sure that all your fittings are at least 1.5" TC.

Will you make me a new false bottom on my MLT?