Good coolers to convert to MLT?

So I've seen some great info on converting a rubbermaid round cooler and the coleman on these forums and in the Brew Wiki.

I have a question regarding the heat retention for these two models....how well do they hold over the course of a 60min mash?

I picked up this pretty generic 48qt coleman ($18) from walmart and gave it a bench test with just 155deg water and it lost like 12 degrees over 60min so needless to say that one will be going back to wally world.

Soooo from some your experiences....what coolers seem to hold the best?

Don't be so quick to return that Coleman. There's a couple of things that will help stabilize temperature and minimize loss:

1) Preheat the MLT. A 'cool' cooler (ha!) will suck away heat. I usually add 180 degree water (1-2 gallons) to my MLT and let it absorb the heat for 10-15 minutes. Dump and save this water for clean up later- no need to waster water.

2) Calculate your strike water temps accurately (software helps). Measure the temp of your grain before doughing in and base your strike water based on this.

3) If you have a really big headspace in the cooler based on a small grain bill, closed cell foam laid on top of the grain bed will keep the heat in.

I usually only lose a degree or two over the hour long mash.

+1 on the closed cell foam. I've only done 1 AG so far, but use a 10 gal, orange, home depot mash tun. I was a small batch, 8 lbs of grain, and I cut a section of 2 inch styrofoam to cover the grains.

I did a 90 minute mash and only lost 1 1/2 degress

Many cheap coolers just don't have the insulation needed to maintain mash temperatures, esp if you plan on doing any outdoor brewing. Consider one of the round rubbermaid drink coolers or spend a few extra bucks now on something like a Coleman extreme which will maintain temp well, even on cool days.

Yeah I added 170 degree water and let it cool to 156 degree before closing lid.

What excatly is closed cell foam?

I don't know about the rest of the coolers, but I have one of those Home Depot rubber maid 10 gallon ones. I don't preheat the tun, and I pour in 168F water in order to hit a mash temp of 152F. I close it up for the entire 60 minutes, and the temp when I am finished is 150F. I have not yet tried this in the winter, when the ambient temp in my garage is much lower but I don't expect too much of a difference.

Twohead....do you close up your cooler as soon as you add the 168 or do you let the temp stabalize closer to the 152 1st before closing?

Be careful shopping at Target stores. I almost picked up a $12.00 CUBE, Till I felt it and realized that the walls were about 1/3 as thick as the standard quality Cubes I've seen at all the other Big Box stores.

I use a 52quart Rubbermaid (the 5 day one) I don't preheat, beersmith will give you a strike water temp to compensate. I do put a little weight on the lid, and I have never lost more than 2 degrees.

Check my sig. It's pretty freakin good and cheap. The drain is recessed in the floor so it drains like a champ.

Coleman Xtreme, it looks like it was designed by a homebrewer. Minimal - I mean, MINIMAL temperature losses when preheated, and what's awesome is that the drain it slotted into a channel at the bottom of the cooler. This means that deadspace is essentially nil. I think it was about $20 for a 36-quart cooler.

Don't go by dry-run numbers. Without the mass of the grain bill, my cooler drops 4-5 deg within 60 minutes, but with the grain, it may lose 1 deg or so. The grain makes all the difference in the world.

Sounds good....I found a 36qt coleman extreme for like $29.00 out here @ a bass pro shop...I think I'll go get that one.

9 gallon should be sufficient i would think...has anybody run into recipes were a 9 gallon mlt wouldn't be big enough?

Just as a data point, the 5 gallon rubbermaid drink cooler I picked up at wally world for about $16 loses about a degree over a 60-minute mash. I think using a smaller cooler for smaller grainbills helps in keeping heat losses down.

Diablotastic said:

Sounds good....I found a 36qt coleman extreme for like $29.00 out here @ a bass pro shop...I think I'll go get that one.

9 gallon should be sufficient i would think...has anybody run into recipes were a 9 gallon mlt wouldn't be big enough?

Click to expand...

Yes this one https://www.homebrewtalk.com/showthread.php?t=63737&page=12:D

That's a huge beer though. That's why I went with a 52 quart cooler, there's not many 5.5 gallon grain bills that won't fit in there. And you can easily do average sized 11 gallon batches. It's the perfect compromise.

the_bird said:

Coleman Xtreme, it looks like it was designed by a homebrewer. Minimal - I mean, MINIMAL temperature losses when preheated, and what's awesome is that the drain it slotted into a channel at the bottom of the cooler. This means that deadspace is essentially nil. I think it was about $20 for a 36-quart cooler.

Click to expand...

One question....would that channel at the bottom of the cooler (where the drain is) actaully impede the ability to rinse the entire grain? Would the liquid try and pool in that area as apposed to getting an all over grain rinsing affect virtually leaving some of the gains a bit un rinsed?

Diablotastic said:

One question....would that channel at the bottom of the cooler (where the drain is) actaully impede the ability to rinse the entire grain? Would the liquid try and pool in that area as apposed to getting an all over grain rinsing affect virtually leaving some of the gains a bit un rinsed?

Click to expand...

Not at all, that's how my cooler drain is. Once the liquid get's to that point in the cooler it's rinsed as good as it's going to get. That channel is actually under your manifold/braid.

I use a 10 gallon rubbermaid round cooler with a false bottom. I've only used it once, but I didn't lose a single degree of temperature over an entire hour. My deadspace is less than 2 cups.

I have a 50 qt Rubbermaid. The one with the split top. I lose about 10-11 degrees to the cooler on warm-up but only about 1 degree an hour after that. Pretty good if you ask me.

Diablotastic said:

Twohead....do you close up your cooler as soon as you add the 168 or do you let the temp stabalize closer to the 152 1st before closing?

Click to expand...

I've found that with a typical grain bill (12-16 lbs), I'll hit 152 almost right on the money every time with my water at 168F. I dough in, stirring thoroughly and then take my temperature. On occasion it has been 1-2 degrees off, in which case I'll add 2 quarts of hot or cold water depending on if I want to raise or cool.

Thanks for all the info guys....I settled on the 52Qt Coleman extreme...found it at Sears for $30.00

Diablotastic said:

Thanks for all the info guys....I settled on the 52Qt Coleman extreme...found it at Sears for $30.00

Click to expand...

you won't be disappointed.

these things hold heat very very well

I am in the middle of putting to together my all grain system, and had looked at those split top coolers. I had shied away from them fearing the heat would leak out the seam at the top. But after reading this... I think I will be en route to sams club to pick one up.

I have a round rubbermade 10 gallon MLT and a 10 gallon split top rectangular cooler. I'm thinking of switching back to the rectangular cooler (I got the rubbermade when buying out a homebrewer that was quitting).

The rectangular cooler holds temp better for me and has a depression in the bottom of it to lay the stainless braid in for draining. And since it is wider than it is tall I find it easier to stir. I used them both on the 999 barleywine (split grain bill) and I actually got a lot clearer wort out of the rectangular cooler, I don't know why (Perhaps because it drains slower?) I batch sparge.

well i was going to go for the orange RUbbermaid, but sounds like the rectangular coleman extreme is the cooler to have! I like the flatter design. The cooler i'm currently using can't hold heat to save it's life. I mashed for about two and a half hours last night and after adding a third of my (boiling) sparge water I ended up partially draining some mash, boiling, and adding back. That's a decoction mash, right? I guess I could just look it up.
Can I use FlyGuy's conversion specs on this cooler?

Yeah I'm in the process of cutting my copper manifold up as we speak.

As far as the 52QT coleman extreme goes....the manifold is quite easy to assemble....I don't seem to have to use the suggested 45degree fittings as suggested in the brew wiki because my fitting seems to be pointed up at an angle


pretty simple conversion all n all to this point

I use the Coleman extreme 52qt and think it's perfect for the job. I add 175 degree strike water and close the lid for 5 mins to preheat,then dough in and stir till my msh temp settles down to about 152-155. During the summer I get zero heat loss with a 60 min mash.