2 mash tuns for 1 brew


All grain noob here. I hope this a simple question… Can I use 2 - 5 gallon coolers to mash a larger amount of grains instead of buying 2 - 10 gallons coolers?

In theory, sure. Sounds like a pain to me, though. Here are my concerns:

  1. Any water treatment is partly dictated by the grains in your mash. Are you sure your c60 is evenly distributed between the two tuns?

  2. Runoff one cooler, add sparge water, Runoff second cooler, add sparge, Runoff first sparge, Runoff second sparge, stop when you get to preboil volume. That just sounds like a three stooges act to me.

  3. More stuff to clean. I hate cleaning out one tun, so two sounds like a huge pain.

Yes you can but you can also mash your base grain s in your tun and just steep your specialty grains. If you still can’t fit it in your tun try mashing thick and double sparge. I used to do that and still got 80%


I too ran into the problem of a 5G mashtun being too small for big batches. Solved the problem by using two BIAB bags in a standard rectangular cooler. That way I can still use the cooler 99% of the year and use it as a mashtun for the 2-3 large grain bill batches per year.

I’m really sorry, but I have rolled laughing at the comment. I can see Curly doing this whole procedure saying “oh!, wise guy aye?!?! nuk nuk

What would be my water to grain ration if I were to mash thick? When double sparging, do I skip the “mash out” process?

1.25 QTS/lb is probably a good guess. You could probably do up to about 12lbs in a 5. How much grain we talking? You could go thicker as long as you can get all the grain wet and mixed you will get conversion.

No, do the mash out and drain. Then just rinse through the grain to reach your target volume. Remember the grain will not absorb any more water so what you rinse with is the amount you get out. Keep your eyes out for a bigger cooler at tag sales. Any type will work. I got one without a spiggot and just drilled a hole

I’ve mashed at 1qt/lb without issue. I’ve heard of people going down to around .8qt/lb but haven’t done so myself. Like BC says, just fill your tun with sparge water and drain, repeat until you have the wort you need. I’ve never seen a benefit of a mash-out, but that’s just my system.

Excellent! Thanks for the feedback!

I have used two mash tuns many times in the past before I bought my 120 qt. There are pics on my website of me using a 48 and 60 quart Igloo. I just make sure my two grain bills are ratio’ed accordingly and then I fly sparge both at the same time.

Hey, looks like yer having a sandwich whilst brewing! Up in the right corner, what kind? Sneezles61

That sandwich would be a square colander.


The pics I’ve seen of your bar area are so beautiful, you could charge admission. I’m surprised to see such a ghetto looking brewery setup :joy::joy:

Nothing wrong with it tho.

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That’s close to 10 years and 600 batches ago and many things have changed. I have a sweet 25 gallon brew cart I built for myself and also built a 15 for my son and one for my buddy.

Ahhh, That makes sense. I actually seem to recall pics on that setup from the old forum.

Here is a photo of my 25 gallon brew cart and the 15 gallon brew cart I made for my son for his wedding last year

And here is the one I am currently building for my buddy. It is my first propane unit; the others are natural gas.