Mash/Lauter tun dimensions

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Mar 2, 2005
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Columbus, MS.
Could you please tell me the dimensions of your cooler and the depth of your grain bed with the ammount of grain you use? I am trying to size up a cooler for my mash/lauter tun.

I have been doing a bit of research and just getting confused. I would like to make one which could serve for both 5 and 10 gallon batches. I don't want to get one which could do 10 gal batches only to find that the grain bed is too shallow when doing a 5 gal batch...

John Palmer's site recommends 4" min depth but prefered 8-18" depth. Furthermore :

John Palmer's site
So, you take your typical batch size (5) and multiply that by your typical OG (1.050) and determine how many pounds of grain that equals, using your typical yield (30) in pts. /lb. /gal. Thus, 5*50=250, and 250/30=8.3 lbs. At a ratio of (2) quarts per pound, the total volume of this mash would be 8.3*(42+32)=616.6 fluid ounces or (dividing by 128) 4.8 gallons. So, I would recommend either the 24 quart rectangular or the 5 gallon cylindrical.
Table 21 - Volume of Unit Mash Units

Volume at Mash Ratio

Volume of Grain Alone


@ 1 qt/lb. = 42 fluid oz.

10 fluid oz.


@ 1l/500g = 1.325 liters

325 milliliters

I dont quite get this. It says to me that 1# of grain volume would be equivalent to 10oz of water volume. So (making the math simple) 10# of grain would have a displacement of 100 oz of water. A 48qt cooler would be 1536 oz (48qt * 32 oz per qt). The grain would occupy 6.5% of the volume (100 / 1536). If the dimensions of the cooler were 9x14 with a depth of 10" then this would have a grain depth of 0.65" (10" * 6.5%) . I know I know... I've got something completely wrong, no way you have just 2/3" of grain bed... what is it? Do the grain swell several times their original size? I don't think this is it with my experience from steeping... I am reading this wrong apparently. Surely the grain takes up more volume than this.

Well, I've done my homework trying to keep from bothering you with details, but at this point, I need a hand.

I want to use a rectangular (square) cooler since making the drain manifold would be easier (vice a round manifold). The 10gal gott cooler has a surface area of 122 sq. inches. I have found a square cooler with inside surface area of (13x13) 169 sq. inches. This is less than most rectangular coolers (11x18 = 198 sq. inches) . I am hoping that this cooler would give me sufficient grain depth for my 5 gal batch grain bill yet not get too deep for a 10gal batch grain bill. I just can't calculate the grain depths until I get past this hump.

Thanks a TON... I'm really ready to get this done so I can move to my AG!!!


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Jan 15, 2005
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Sorry no one has answered this post.....

When I was doing my research for my MLT, I considered a bigger cooler for large batches down the road.
In my opinion, this is the cooler to use. You can't go wrong with this one and I think your dimensions would work out almost perfectly for at least an 8 inch grain bed. 5 gallon batches wouldn't work in this, but 10 definitely will. And high gravity 10 gallon batches as well. I think you'd be able to get enough grain/water in this sucker for a 1.090 gravity beer.

You could easily make a bulkhead and a steel braid manifold thingy. If oyu need help with that I'll send you the list of the exact parts I bought from Lowe's to get a nice tight seal with no leaks.


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Apr 13, 2005
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Knoxville, TN
A 50 quart cooler is serviceable for both 5 and 10 gallon batches. I use this size for all my brewing, but I only brew 5 gallons at a time. A friend of mine uses this same size to brew 10 gallons, but the practical limit here is a gravity of about 1.058. At that gravity, the tun is REALLY full. The 5 gallon grain bill is about 5 - 6 inches deep.

The 50 quart model is a good size to start with. They are less than $20 and easy to outfit with valves and such. If you find out later that you need a bigger tun, you won't feel so bad about chucking it and starting over.