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This is how big your Mash Tun needs to be

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Bobby_M

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There seems to be a huge uprising in the number of new all grain brewers and the persistent question is "how big of a tun do I need?" It depends on what your batch size, efficiency, and desired OG is. Here's the easy way for you to decide based on your needs.




Keep in mind that even if you think you might want to do both 5 and 10 gallon batches, odds are your really high gravity beers will be 5 gallon batches. Who needs 10 gallons of barleywine?

Just for example, a 10 gallon mash tun can do 5 gallons of 1.118 barleywine (~11% ABV) and 10 gallon batches of 1.060 IPA (~6% ABV). I personally think something in the 50-60qt range is most flexible in that regard if you don't mind a square/rectangular cooler.

If you want to figure for larger or smaller batch sizes, take the number in the "Max Gravity Units" column and divide that by your desired batch size.
 

McKBrew

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Excellent chart Bobby. I will repost this from now on when answering that question.
 

Bernie Brewer

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Nice chart, Bobby. I'd like to add that new AG brewers should think ahead. You may THINK that all you need is a 5 gallon tun, but are you going to outgrow it??? If there is even a small possibility that you may indeed outgrow it, get the bigger one right way. It'll save you $$ in the long run.
 

wildwest450

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Nice chart, Bobby. I'd like to add that new AG brewers should think ahead. You may THINK that all you need is a 5 gallon tun, but are you going to outgrow it??? If there is even a small possibility that you may indeed outgrow it, get the bigger one right way. It'll save you $$ in the long run.
+1, 52 qt ftw!!
 

TheMan

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I'm very new to the all grain thing, I have only started reading about it a couple days ago and I'm trying to figure out equipment and all. Can you help explain what you mean by
If you want to figure for larger or smaller batch sizes, take the number in the "Max Gravity Units" column and divide that by your desired batch size.
If I want to do a 15 gallon batch of 80% efficiency with 1.105 OG I then take 1054/15 which equals 70.26. So I need at least a 70 qt tun for this? I am a bit confused and don't think I am doing it right.

Edit: After checking some of my numbers against the chart numbers I am certain I'm doing it wrong...
 
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If you want to figure for larger or smaller batch sizes, take the number in the "Max Gravity Units" column and divide that by your desired batch size.
Sorry, to clarify, a 52qt, assuming 80% eff. is good for 1054 total gravity points. In 15 gallons, that's about 1.70 max OG. (1054/15 = 70).

If you know your expected efficiency, you can try this. To calculate for mash tun size requirement in quarts (80% efficiency of course), it's (Desired OG x Batch Size)/17 = mash tun size

Let's say you want 1.088 x 15 gallons, it's (88 x 15)/17= 77 quart tun.

If you're going to be doing regular high gravity beers at 15 gallons, go with a 100qt.
 
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I also thought since the chart doesn't cover all sizes:

Each quart of mash tun capacity can handle:
Max grain @ 1.25qt/lb = .6lbs
Total strike .1875 gallons
Total in tun .2435 gallons
 

TheMan

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Wow, thank you Bobby! That second explanation you gave helped a ton. So basically I calculated the Max OG, not tun size needed. I think I have just one other question...the 17 you divide by, is that from the max OG calculation? Whereas, a 52 qt at 70% efficiency in 15 gallons would be (767/15 = 51) Meaning max OG of 1.51. I would divide by 15 instead of 17 in this equation: (Desired OG x Batch Size)/17 = mash tun size?

Or is the 17 a static number and I'm just over thinking this?

Sorry, to clarify, a 52qt, assuming 80% eff. is good for 1054 total gravity points. In 15 gallons, that's about 1.70 max OG. (1054/15 = 70).

If you know your expected efficiency, you can try this. To calculate for mash tun size requirement in quarts (80% efficiency of course), it's (Desired OG x Batch Size)/17 = mash tun size
Thank you for your patience with me, I'm trying to understand.
 
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The 17 is max gravity points per quart of mash tun at 80% efficiency. Another way to say it is that it would be 21 gravity points per quart at 100% efficiency.

You can rewrite the formula like (desired OG x Batch Size in gallons) / (21 x estimated efficiency in decimal) = mash tun size in quarts.

I think it's safe to assume a 70% efficiency though so just use 15 gravity points per quart of mash tun as an estimate.
 

TheMan

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I've read and been messing with the numbers now for a little bobby, I get it now. Great write up, hopefully they sticky this, I'm sure it will help many people. Looks like an 80 qt. will be optimal for my needs.

Thanks again for helping someone as mathematically challenged as myself!
 

jldc

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Thanks for the post.

My comments:

If you mash looser than 1.5 qt/lb, you will need a bigger tun.

A 5 gallon tun isn't a total waste. I use mine for smaller beers and as a HLT. Also, if you decide to move from a 5 gallon to a 10 gallon cooler, you may be able to replace the plastic valve mechanism or plug the hole and turn the cooler back into a cooler again.

All of that said, a 10 gallon cooler is only about $20 more than a 5 gallon cooler (if you're buying and not scavenging), and is money well-spent.
 
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I was going to include all kinds of variables but then the table would have been quite large. I picked 1.25qt/lb because it's pretty common.
 

babalu87

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Also need to consider the dead space in the lid of the cooler.

Cooler manufacturers use that space for volume but we cant.
 

Jkane101

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Thanks Bobby. One day i need to drop down to Piscataway to watch you in action. I'm itching to go AG
 

mindslat

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Howdy! I'm trying to pick a cooler out for a new system I'm trying to build up. I'm looking to make 5 gallon batches at barley wine strength without sparging. I'm looking at about 54% efficiency, correct me if I'm wrong. How do I plug this in.

I hope someone's still watching this thread. great sticky!
 
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Bobby_M

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That's where I just grab my BTP software and mock it up. Assuming you mean a STRONG barleywine like 1.100, at 55% efficiency it would take about 25lbs of grain with 10 gallons of water (that's a 1.6qt/lb ratio) to drain off about 7.25g of wort. The total volume in the MLT would be 13.5gallons. A 52qt cooler would be borderline but doable.
 

Drunken Monk

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So I just finished building a five gallon mash tun from a round rubbermaid cooler (before reading this thread). I'm a noob at AG so bear with me. My question deals with sparging. If I'm maxed out at 12 lbs as the chart says, can I do a batch sparge or do I have to fly sparge? Does one's sparging method make any difference relating to the max grain/OG the tun can handle?
I ask because I plan on doing EdWort's Haus IPA this weekend and I need to know if I should build a sparge arm. I'm assuming batch sparging shouldn't be much different. I would just have to do more batch sparges to get to my target volume?
Thanks for the help.
 

bakins

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Does one's sparging method make any difference relating to the max grain/OG the tun can handle?
Only if you sparge or not. Sparge technique doesn't matter. (Though I suppose, if you fly, you want room to have an inch of water above the grain.)
 

Spannuta

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sorry if this is my own stupidity, but i do not see the chart anywhere on the posts. I assume that it was an image in Bobby M's original post. Do I have to be a premium supporter to see images? I didn't think so. Maybe its the computer I am on. Any help? Maybe re-paste it in a new post or let me know if I can find the chart posted somewhere else. Thanks!
 
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Bobby_M

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So I just finished building a five gallon mash tun from a round rubbermaid cooler (before reading this thread). I'm a noob at AG so bear with me. My question deals with sparging. If I'm maxed out at 12 lbs as the chart says, can I do a batch sparge or do I have to fly sparge? Does one's sparging method make any difference relating to the max grain/OG the tun can handle?
I ask because I plan on doing EdWort's Haus IPA this weekend and I need to know if I should build a sparge arm. I'm assuming batch sparging shouldn't be much different. I would just have to do more batch sparges to get to my target volume?
Thanks for the help.
The chart is based on how much you can mash with a tiny bit of headspace remaining. You would be able to fly sparge no matter what but your batch sparge infusions might have to be broken into two half volumes if you've got it maxed out.
 

Spannuta

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Keith_Mahoney

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I have a question but it's looking at size in the opposite direction. I plan on getting a 10 gal cooler because l like strong beer ( I don't typically drink anything less than 7% and drink beer much stronger than that daily.) If I wanted to brew something a little lighter for the wife (5gal batch) how low could I go on the OG with still having a thick enough grain bed? I think Palmer recommends at least 8" but definitely no less than 4

Also is the OG in your chart pre or post boil?
 
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The OGs in the chart are post boil. If you batch sparge, the bed thickness doesn't matter at all. If you prefer fly sparging, you could just decide to batch sparge low OG 5 gallon batches.
 

Keith_Mahoney

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Actually I am planning on setting up a HERMS system, no in between stuff, I'm jumping in with both feet. I will get a keggle for a boil pot. A ten gallon drink cooler with false bottom for MLT and convert my 7.5 gal aluminum pot to an electric HLT.

Most of my beers will be over 1.070 but will this set up do beers around 1.050? And is a false bottom they way to go in a HERMS setup?

Thanks for your help.
 

SamuraiSquirrel

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Just a thought but bigger is not always better. I have a ten gallon cooler and find that for smaller beers where I am filling less than 50% of the cooler volume I lose about 5 to 6 degrees over the 60 minute mash. I am thinking about getting a smaller cooler for smaller O.G. beers and using my 10 gallon cooler only for beers that the 5 or 7 gallon cooler can't hold. The dead space in the cooler seems to contribut to heat loss over the mash. ................ maybe I just have a crappy cooler though.
 

woopig

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I'm sure this has been covered, but I'm having trouble finding it. All the talk seems to be about having a mash tun that's big enough. I'm deciding between the NB 5 gallon and 10 gallon cooler system. So, if I still want to do some 5 gallon batches, am I going to regret getting the 10? I thought I had heard something about needing an adequate grain bed depth, but nobody seems to talk about that much. Any thoughts?
 

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