# How much can my mash tun hold

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#### YOpassDAmike

##### Well-Known Member
I have a 10 gallon igloo cooler with a stainless steel false bottom for my mash tun. I am breweing a big russian imperial stout that will be using 22.5lbs of grain. With 22.5lbs of grain in my 10 gallon igloo cooler, how many gallons of water can I fit in my mash tun with the grains. I really don't care about my quart per pound ratio, I just want to fill my mash tun to the top to eliminate all of the dead space. I am guessing with 22.5lbs of grain that I can fit 8 gallons of mash water, does this sound right? Does anyone know how to do the math?

Thank you.

#### timdillon36

##### Well-Known Member

http://www.rackers.org/calcs.shtml

#### CA_Mouse

##### Well-Known Member
^^This^^

http://www.rackers.org/calcs.shtml

Your 10 gallon cooler should be able to handle that, but just barely. I would mash a little thicker than normal and sparge with a little more water to make the pre-boil volume.

#### SpeedYellow

##### Well-Known Member
You can do it by hand thus:

Needed mash tun size in gal = [lbs of grains] x 0.12 + Strike Water Gallons

Solving for Strike Water means you'll fill a 10-gal cooler with 22.5 lbs of grain and 7.3 gal strike water.

A note of caution-- often the actual volume of coolers is less than the listed size. So you should measure the actual volume yourself. It can easily be 1 gal overstated!