MLT size

[CorneliusAlphonse]

Hi all. I plan to get into all-grain brewing this summer when I have a bit more spare time (and money). now I hate to raise a topic that has been mentioned on here so many times before, but I am wondering what I should get for my MLT. I don't expect I'll be making anything stronger than an IPA, and only 5 gallon batches. (i'll be kicking myself for saying this..)

I read through Bobby M's post about sizing a MLT, and scoured some hardware store websites for coolers. Would a 33 quart cooler be a good size to get? would it let me make a brew around 6 or 7%?

thanks for any help

 

[gunner65]

I just got a rubbermaid/home depot 10g for $37 in the store. You have to go in and find them and they are sometimes hard to find. In my store they were on the top shelf in the grilling section and you cannot locate them online. I would go bigger if you can swing it. At this point I really dont see anything bigger either but I would hate to have to make a second investment on something I should have done to begin with. I mean the fittings are the same price for either size cooler so the only difference would be about 10-15 extra bucks on the larger cooler.

 

[Walker]

Yeah, 33 quarts should be fine for any strength 5 gallon batch. I've got a 40 quart cooler and have done a couple *10* gal batches with gravities up in the mid 1060's. That pushes the limits for me (VERY full tan), but it works.

 

[CorneliusAlphonse]

had a little trouble with my imperial conversions - 10 gallons is 40 quarts - i can probably splurge for the extra 7 quart . I'll try looking at home depot this weekend to see if they have the 10gal round ones i didn't see them on their site

 

[Scooby_Brew]

I would say you need your MLT size to be at least 50% larger then your batch size. For your 5 gal batches (20L) you need 7.5 gal (30qt, 30L) size MLT, that's the minimum.

Strangely enough, the same rule of thumb applies to the BK and fermenter size: you need about 50% larger BK and fermenter then the size of your batch

 

[mightynintendo]

A 10 gallon cylindrical home depot water cooler makes an excellent MLT for 5* gallon batches.

*A 5 gallon batch generally means you need to brew 6 gallons. And brewing 6 gallons with a rapid boil-off (1.48 gallons/hour) will mean you need about 8.22 gallons of water to do a 90 minute boil. If you batch sparge, depending on your mash water/grain ratio, your sparge will likely almost completely fill up the 10 gallon water cooler when using 11-13 pounds of grain.

Also, I have found that the water cooler retains heat very well, losing ~1 degree F in 60 minutes in most environments with the lid on. These work great for lautering. I get 75% efficiency (with water adjustments) every single time.

EDIT: Also, to address your question about 6 or 7%: the ABV is more determined by the amount of fermentable sugars in your wort (which has a lot to do with your mash temp) and the attenuation of your yeast than the size of your cooler. I think you should be more focused on the gravity you are capable of achieving with the size of your cooler. Experience has shown me that for 6 gallons post-boil, the 10 gallon cooler can handle up to about 1.090 OG from grain alone.

 

[Walker]

I would say you need your MLT size to be at least 50% larger then your batch size. For your 5 gal batches (20L) you need 7.5 gal (30qt, 30L) size MLT, that's the minimum.

50% would certainly give you breathing room, but I can definitely do 10 gallon batches using a 10 gallon cooler, so I don't support your "50% larger is the minimum" rule.

 

[Walker]

*A 5 gallon batch generally means you need to brew 6 gallons. And brewing 6 gallons with a rapid boil-off (1.48 gallons/hour) will mean you need about 8.22 gallons of water to do a 90 minute boil. If you batch sparge, depending on your mash water/grain ratio, your sparge will likely almost completely fill up the 10 gallon water cooler when using 11-13 pounds of grain.

I'm going to argue against this one, too. Most of my recipes are around 11 lbs, and I've got a few gallons of space left in the tun when I batch sparge. The sparge volume is usually 4 gallons, sometimes less. My wet grain does not take up the other 6 gallons of space.

 

[mightynintendo]

I'm going to argue against this one, too. Most of my recipes are around 11 lbs, and I've got a few gallons of space left in the tun when I batch sparge. The sparge volume is usually 4 gallons, sometimes less. My wet grain does not take up the other 6 gallons of space.

Well the only relevant bit of information here to compare to what I said would be how much wort you collect in the end which you didn't share. Do you collect 8.22 gallons of wort at the end of your mash/sparge??? If so, and if you use less than 4 gallons to sparge, then you're mashing with around 6 gallons of water. 6 gallons of water in 11 pounds of grain MIGHT fit in the home depot 10 gallon cooler but I doubt it.

 

[Walker]

Here's the water volumes I use for one of my APA recipes that I brew often (as an example). The grain bill totals 11 lbs exactly.

I dough in with 4 gallons of water (a little less than 1.5 quarts per lb of grain)

I add 1 gallon of mash-out water at the end of the mash.

From this 11 lbs of grain and 5 gallons of water in the tun (above which there are a few gallons of space), I will collect between 3.25 and 3.5 gallons of wort in the kettle.

I then batch sparge with another 3.25 to 3.5 gallons of water, all of which ends up in the kettle because there is no more water loss to grain or dead space after the first runnings are taken. Sparge water all comes back out.

This leaves me with about 6.75 gallons in the kettle at the start of the boil.

I boil off about 5 quarts over the hour, finishing with 5.5 gallons in the kettle.

5 of this makes it into the fermenter.

So, no I don't collect 8.22 gallons of wort in my kettle. I would have to boil that for 2 hours to get it down to the volume I want.

Efficiency for me is roughly 77%.

 

[mightynintendo]

Well we have a several differences that change things around a bit.

1. I boil off 6 quarts per hour instead of 5.
2. I do 90 minute boils instead of 60.
3. I aim for 6 gallons post-boil instead of 5.5
4. I don't do that 1 gallon addition at the end of the mash
5. I have a lower efficiency (75%)

But I was accounting for this, and 11 pounds of grain is FINE! 11 pounds of grain is going to give you a gravity of 1.0585 (77% efficiency, all-base-malts, 5.5 gallons) which is far below my recommendation of 1.090 as the far-end grain-only gravity one could get for a 6 gallon batch in the 10 gallon home depot water cooler. At 1.090 things are going to get pretty crowded in the 10 gallon cooler.

 

[CorneliusAlphonse]

A 10 gallon cylindrical home depot water cooler makes an excellent MLT for 5* gallon batches.

*A 5 gallon batch generally means you need to brew 6 gallons. And brewing 6 gallons with a rapid boil-off (1.48 gallons/hour) will mean you need about 8.22 gallons of water to do a 90 minute boil. If you batch sparge, depending on your mash water/grain ratio, your sparge will likely almost completely fill up the 10 gallon water cooler when using 11-13 pounds of grain.

Also, I have found that the water cooler retains heat very well, losing ~1 degree F in 60 minutes in most environments with the lid on. These work great for lautering. I get 75% efficiency (with water adjustments) every single time.

Thanks. I think I will try to get one of the 10 gallon round coolers - everyone seems to like them, and they come with a spigot so they are easier to modify into an MLT.

EDIT: Also, to address your question about 6 or 7%: the ABV is more determined by the amount of fermentable sugars in your wort (which has a lot to do with your mash temp) and the attenuation of your yeast than the size of your cooler. I think you should be more focused on the gravity you are capable of achieving with the size of your cooler. Experience has shown me that for 6 gallons post-boil, the 10 gallon cooler can handle up to about 1.090 OG from grain alone.

Interesting... I thought that the OG post-boil was indicative of the amount of potential alcohol, but it makes sense that the mash temp is a bigger issue (enzymes and whatnot changing the sugars to be fermentable).

 

[mightynintendo]

I thought that the OG post-boil was indicative of the amount of potential alcohol, but it makes sense that the mash temp is a bigger issue (enzymes and whatnot changing the sugars to be fermentable).

Well the OG IS indicative of potential alcohol in a big way. But it's definitely not the final word. A 1.052 OG beer could easily finish from 6% ABV down to 4% ABV.

 

[gunner65]

had a little trouble with my imperial conversions - 10 gallons is 40 quarts - i can probably splurge for the extra 7 quart . I'll try looking at home depot this weekend to see if they have the 10gal round ones i didn't see them on their site

Like I said they are not listed online. You have to go in and ask.

 

[snevey]

Just remember, the more dead space you have in your tun, the harder it will be to maintain consistant temps during your mash... I had 10 lbs of grain and 3 gallons of water in my 5, yes FIVE, gallon igloo round cooler, and I swear I had at least 8 inches from the top of the water/grain to the 5 gallon mark on the inside of the cooler... My next batch, I'm going to push it a little and up my grain bill to about 12 lbs to see where that gets me. I was mislead on this board too about going overkill on my tun size.

 

[Walker]

At 1.090 things are going to get pretty crowded in the 10 gallon cooler.

In general, I agree, but you have to also consider that you might have to change your standard process.

In the not-too-distant past, the "norm" was considered mashing with 1 quart of water per pound of grain (I believe Papazian suggests this in his book). That's pretty thick IMO, and folks tend to mash much thinner than this. But, if you are trying to make a beer with a large grain bill, you don't have to let the tun size rule over you. A thicker mash is an option. In my example above, if I switched from 1.5 to 1 quart per pound on the water, I just reduced the amount of water for mashing by 33% (4 gallons falls to under 3 gallons), which would free up even more room in the tun.

Another thing is the sparging... On the 10 gallon batches I have done, I do not have room to do a single large batch sparge, so I cut the sparge water in half and do two smaller sparges. When I did this my efficiency ended up going up to 81% or so. I think there is a thread on here somewhere talking about how 2 small batch sparges hits a sweet spot on efficiency. My own limited experience backs this up.

I've no desire to make a beer with a 1090 or higher gravity, but I'm sure I could do it with my 10 gallon cooler if I mashed "old school" and did multiple batch sparges.

 

[snevey]

Walker, you're a great source of usable knowledge. Thanks for this. And your avatar rocks!

 

[CorneliusAlphonse]

Just remember, the more dead space you have in your tun, the harder it will be to maintain consistant temps during your mash... I had 10 lbs of grain and 3 gallons of water in my 5, yes FIVE, gallon igloo round cooler, and I swear I had at least 8 inches from the top of the water/grain to the 5 gallon mark on the inside of the cooler... My next batch, I'm going to push it a little and up my grain bill to about 12 lbs to see where that gets me. I was mislead on this board too about going overkill on my tun size.

That's why I had been thinking smaller originally... but having 3 gallons of water with 10 pounds of grain is like 1.2 quarts per pound right? reading from Walker's post, this seems to be a little on the low side, you could reduce the head space by using more mash water? I like the looks/storability of the 10gal round coolers, space is kind of at a premium for me. might be able to stash some


I have a feeling that when I go to the effort of doing all grain, I'm going to want to do 10 gallon batches. I can just split it up into two 5gal fermenters right?

 

[Walker]

having 3 gallons of water with 10 pounds of grain is like 1.2 quarts per pound right? reading from Walker's post, this seems to be a little on the low side

1.2 is an OK amount. I used to use about 1.1-1.25 and only recently started mashing thinner at 1.5. I think I've seen some folks claim to use upward of 2 qt/lb. It's a matter of personal preference, really. Thinner mashes seem easier to deal with (stirring, etc).

I have a feeling that when I go to the effort of doing all grain, I'm going to want to do 10 gallon batches. I can just split it up into two 5gal fermenters right?

Yes, you can just split them. It's a nice way to see the side-by-side effects of different yeast on the same wort, too. I did 10 gallons of pils with a friend. He pitched dry swiss lager yeast in his 5 gallons and I pitched a starter of liquid bohemian lager in my 5 gallons. Both sat side-by-side in my lagering fridge until they day they were kegged.

His pils was really really good. Mine sucks. Undrinkable. (I think my yeast was bad.)

 

[mightynintendo]

Another thing is the sparging... On the 10 gallon batches I have done, I do not have room to do a single large batch sparge, so I cut the sparge water in half and do two smaller sparges. When I did this my efficiency ended up going up to 81% or so. I think there is a thread on here somewhere talking about how 2 small batch sparges hits a sweet spot on efficiency. My own limited experience backs this up. ...

Interesting, I've actually never considered doing that. I can see how it would work though. Even if not doing a 10 gallon, say you're making a RIS with a gravity of 1.1--. You could definitely make it happen with two batch sparges without compromising mash thickness. I'm not a fan of the 1 qt/lb mash one bit.

 

[Walker]

Interesting, I've actually never considered doing that. I can see how it would work though. Even if not doing a 10 gallon, say you're making a RIS with a gravity of 1.1--. You could definitely make it happen with two batch sparges without compromising mash thickness. I'm not a fan of the 1 qt/lb mash one bit.

Yeah.. I thought it was really interesting too.

I have never applied it on a 5 gallon batch at this point. I just did my thing with 5 gallon batches and did a single batch sparge and went about my business.

The multi-sparge was only done on the 10 gallon batches out of absolute necessity and it definitely increased my efficiency. I didn't even plan to do it on that first 10 gallon batch (the ill fated Pils I just mentioned), but when I got ready to dump my sparge water in I realized that there was no f*cking way I was going to get it all in there at once, so I cut it in half and did two rinses.

It was a few weeks later that I read about the 2-sparges giving higher efficiency. I did 10 gallons of porter shortly after that and again did the 2-sparge out of necessity, and found again that I got higher efficiency.

I'm convinced. I might try it on a 5 gallon batch to see if it really has to do with the 2-sparges or whether it's just something else about 10 gallon batches that makes my efficiency go up.

 

[gunner65]

placeholding!!!!

 

[Bensiff]

I can push 1.060 in a five gallon cooler keeping the ratio down towards 1.15. Not ideal, but it can be done. 33qt will be fine, but I would go 40 qt so you can do 10 gallon batches if the need should arise.