# Big Beer, Small Mash Tun

Hey guys, I have a quick question about mashing big beers. I have the 5-gallon all grain kit from Northern Brewer, so it’s a 5-gallon mash tun. I ordered the West Coast Imperial IPA and it’s huge… 14 pounds of grain. At 1.2 quarts of water per pound of grain, no way it’s all fitting in that tun for the mash. Should I mash a little longer, just mash the specified 60 minutes but with less water, or possibly split it up? I have a 2 gallon cooler left from my old partial mash kit that could be pressed into service if necessary. I’m hoping to brew this Sunday so feedback is greatly appreciated

You can mash thick. 1:1 should take up about 4.6g. Is the “usable” space in the cooler 5g or does that somehow include the lid?

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

You could split the mash between the 2 coolers.

Or you can do a reiterated mash: Mash 1/2 the grains as usual. Then mash the 2nd half with the wort produced from the 1st mash.

viewtopic.php?t=51438

you could also mash about 10lbs of grain (or whatever fits well) and then add DME or LME into your boil (there are many calcs for this). i know this isn’t what you were looking for but it’s an easy fix/option that you can’t screw up.

I had this problem two weeks ago with a Belgain Dubbel in a 5gal cooler…Just from experience, if you miss your rest temperature and the tun is already to the top, there isn’t much you can do to heat it up. If you mash all 14 pounds, make sure you get the temperature right.

I bought this same kit and have a similar dilemma. So I have a question to piggy-back on this- Let’s say I have the coolers that supports the 4.6gal to 5.6gal needed to mash.

Mash = 1.25Q*15lbs = 4.6gal
Sparge = 2Q x 15lbs of grain = 7.5gal!

That’s over 12gal! Is my math wrong here? How does this equate to a 5gal kit? Would I just not sparge? How much for mashout? I’m so confused. Any help would be appreciated.

[quote=“jdrulia”]I bought this same kit and have a similar dilemma. So I have a question to piggy-back on this- Let’s say I have the coolers that supports the 4.6gal to 5.6gal needed to mash.

Mash = 1.25Q*15lbs = 4.6gal
Sparge = 2Q x 15lbs of grain = 7.5gal!

That’s over 12gal! Is my math wrong here? How does this equate to a 5gal kit? Would I just not sparge? How much for mashout? I’m so confused. Any help would be appreciated.[/quote]

Your error is in your sparge calculation. Not sure where you got this. Basically the mash strike water gets partially absorbed by the dry grain. So you get less out than you put in.

For the sparge, because the grain is already wet and saturated, you get out what you put in.

With 15 pounds of grain, I would strike with more water if possible. I try to get equal amounts of wort (within reason) from my first and second runnings (second is the sparge). So I would strike with about 5.5 gallons of water and “probably” get a little over 3 gallons of first runnings. Then I would spare with about 4.5 gallons of boiling water and get a total pre boil volume of about 7.5 gallons. I have a big pot, so I boil off about 2 gallons per hour.

Mash as thick as you have to to make it fit in the cooler, then, assuming you’re batch-sparging (or you wouldn’t be asking this question in the first place) do two sparges to fill the kettle.

As others have suggested, if you are batch sparging, mash thick (0.9 qts/lb is fine) and sparge twice. If it doesn’t fit, mash some in a spare kettle or cooler on the side. Or, you could split the batch, maybe do 3 gallons this time and 2 gallons next time. You could even “decoct” some of it by boiling it in a small kettle on your stove for 15 minutes or so at the very end of your main mash, then add it into the main mash after the first or second runnings when it might fit in your cooler easier. Tons of options you could play with.

Looks like 14# at 1.1 qt/lb will just fit. Put the grain in first and then just fill’er up. You’ll get 8.4 qt of first runnings. Then you’ll need to sparge with 16 qts to get 6 gallons of preboil wort, so just batch sparge with 8 qt twice (fill’er up twice) and start your boil.

Easy squeezy.

I’ve found it’s more difficult to get all the grain mixed in if I add water to grain than if I add grain to water. Try adding a little water, then a little grain until you get all the grain mixed in and moistened, then add the rest of the water.

Last time I crammed a lot of grain into my tun I ended up with a lower O G than anticipated.

That’s why you need to sparge twice. Planning for a longer boil helps efficiency too. For a really big beer >1.100 gravity, I’ll plan to collect enough wort for a good 105 minute boil, or more. Basically then you are sparging more, collecting more sugars, and concentrating them down to attain a reasonable efficiency in the 70s like you want. If you don’t sparge twice or don’t boil long, then your efficiency might only be in the 60s.

Thanks for the clarity guys! It is super helpful. I got the sparge 2qt x lbs of grain from the Northern Brewer “How to all-grain brew”…

[quote=“TG”]Looks like 14# at 1.1 qt/lb will just fit. Put the grain in first and then just fill’er up. You’ll get 8.4 qt of first runnings. Then you’ll need to sparge with 16 qts to get 6 gallons of preboil wort, so just batch sparge with 8 qt twice (fill’er up twice) and start your boil.

Easy squeezy.[/quote]
Curious, where did you find the calculation that I’d end up with 8.4qt after the first run?

1. how big is the mash? 1# of wet grain takes up 1/3 qt of volume, so
#grain/3 qt + qts of mash liquor = total volume
14/3 + 14*1.1 =
4.66 + 15.4 = 20.06 qt

2. how much first runnings will I get?
first runnings volume = mash liquor - liquid absorbed by grain (usually about 0.5 qt/lb), so
15.4 qt - #grain * 0.5 qt/lb =
15.4 qt - 7 qt = 8.4 qt of first runnings

If you batch sparge you can add 8.4 qt to fill up the mashtun, and you’ll get 8.4 qt of 2nd runnings. (No need to consider the amount absorbed by the grain because it is still wet from the first time.) And do it again for 8.4 qt of 3rd runnings and you’ll end up with 8.4 qt * 3 = 25.2 qt of pre-boil wort

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