Cheap & Easy 10 Gallon Rubbermaid MLT Conversion

[hlumbard]

I keep seeing this thread come to the top and it always makes me smile. This is THE number one thread that made me think "I can DO THIS!"

 

[reinbrew]

This set up got me 71% efficiency! Very excited! Hit all my temps too.

 

[dropitlikesitshot]

Here is my experience: 10 Gal cooler at HD is not displayed must ask where they're kept. Price $40+tax. All the other parts were easy to find, but three parts differed from the fly guy wiki post. The 1/4 hose clamps turned out to be Nickel plated steel vice stainless steel (which is better). I bought the wrong type of supply hose (explain later), and the 5/8 SS Fender washers was in the bolt pack as previously mentioned (but may not be needed). Finally the O-ring was in a pack not sold individually.
CAUTION!! Hardware stores sell Zinc plated steel items and will be recommended by the store help if you do not tell them your MT will be in contact with liquid. I bought a zincs supply house by accident. Also the 5/8 fender washers that took my on a wild goose chase may turn out to be a lesson learned. I have them inside, but really might be able to go without since I have handle clearance on the outside (original post used three on the outside) and water tight seal inside (where I am using them). I am using them inside now, but may see if it works fine without them later. The total price for the hardware was $40. So, buying a setup from your LHBS might be a better deal considering time and gas.

 

[jtkratzer]

I spent about $80 on mine, but got exactly what I needed without having to buy kits for single parts I needed. I found the 5/8" washers for $0.41 without having to buy a $4 bolt kit. My LHBS charges almost $140 after tax, so saving about $60 is definitely worth it - that's 3 recipes worth of ingridents for basic all grain beers.

 

[klyph]

The hardware really costs $40? Because you can order a Stainless steel bulkhead and valve for less than that.

 

[pikeman94]

I wanted to ping the group to see if anyone out there has had any issues with mash temperature stratification. I am fairly confident that my mash tun will hold the temp within 1 degree F near the bottom of the mash tun, but I am thinking it is a different story near the top. I am zeroing in on this as my issue with my finished beer since my attenuation numbers are in the 80 percentile. The other indicator is that my ABV is usually .75% to 1% over my target ABV. Now my SG is always within .0002 of my target. Thus, I am back to my mash as the culprit.

Anyone have any ideas short of going a RIMS route?

-Pikeman94

 

[klyph]

Have you considered beefing up the lid insulation with spray foam? Most of the lids are just hollow plastic.

 

[o4_srt]

Have you considered beefing up the lid insulation with spray foam? Most of the lids are just hollow plastic.

This. My mlt was cool to the touch during mashing this past weekend, but the lid was quite warm. I am certain I am losing a lot of heat out of the top.

Filling with spray foam before my next brew day.

 

[LKMKLK]

- brass square head plug (Watts A-737)
why is this needed. i dont get the plug factor, shouldnt it flow out???

 

[jtkratzer]

- brass square head plug (Watts A-737)
why is this needed. i dont get the plug factor, shouldnt it flow out???

It's to weight the opposite end down and keep it at the bottom of the MLT.

 

[Quaffer]

I wanted to ping the group to see if anyone out there has had any issues with mash temperature stratification. I am fairly confident that my mash tun will hold the temp within 1 degree F near the bottom of the mash tun, but I am thinking it is a different story near the top. I am zeroing in on this as my issue with my finished beer since my attenuation numbers are in the 80 percentile. The other indicator is that my ABV is usually .75% to 1% over my target ABV. Now my SG is always within .0002 of my target. Thus, I am back to my mash as the culprit.

Anyone have any ideas short of going a RIMS route?

-Pikeman94

I have used my 5 gallon cooler a lot more than the 10. I stir the mash once or twice during the hour because it gets cooler on the bottom. The top layer at first seems extremely stable, but it is so only because it is fed heat from below. The bottom layer cools first. I am converting to RIMS for this reason, and to be able to do step mash.

 

[pikeman94]

I have used my 5 gallon cooler a lot more than the 10. I stir the mash once or twice during the hour because it gets cooler on the bottom. The top layer at first seems extremely stable, but it is so only because it is fed heat from below. The bottom layer cools first. I am converting to RIMS for this reason, and to be able to do step mash.

Quaffer - With removing the lid and stirring, did you maintain your target temp?

 

[Quaffer]

Quaffer - With removing the lid and stirring, did you maintain your target temp?

Nope. It would not be maintained anyway except for at the very top layer. The bottom layer will drop way below target, so by stirring it the temperature evens out throughout the mash. In the 5 gal cooler I drop about 3°F over 60 minutes. It should be less than that in a 10 gallon cooler but I don't have much experience with it yet.

 

[PaulTheGhost]

So I went to my lhbs today...
I talked with one of the more knowledgeable staff members about using a ten gallon cooler as my mlt and she recommended not to use one. She said they're not food grade (not what the description of the cooler says) and that you shouldn't use one because you can't heat it up at the end of the rest (I havnt read anywhere that this is necessary.) She also advised not to use one because her friend brewed a batch and it ended up tasting like bubblegum.
Can anyone shed some light on any of this? Seems like everyone has had good success with their mlts, so her information caught me by surprise.

 

[pikeman94]

Nope. It would not be maintained anyway except for at the very top layer. The bottom layer will drop way below target, so by stirring it the temperature evens out throughout the mash. In the 5 gal cooler I drop about 3°F over 60 minutes. It should be less than that in a 10 gallon cooler but I don't have much experience with it yet.

Sigh....That is what I feared. Since I don't have a large enough mash kettle, I may be forced into the RIMS world.

Of course I will have to test this out with about 6 gallons of water in my 10 gallon mash tun. I would lean towards how your mash tun is performing though.

One thought I had to try to combat this issue was to change out my tube with stainless steal mesh braiding for copper tubing with the stainless steal mesh braiding. Then, I could insert a paint stirring paddle through the lid and operate with a drill at a very low speed. My thought is that this would keep the temp mixed and stabilized throughout the mash.

Thoughts anyone?

 

[pikeman94]

So I went to my lhbs today...
I talked with one of the more knowledgeable staff members about using a ten gallon cooler as my mlt and she recommended not to use one. She said they're not food grade (not what the description of the cooler says) and that you shouldn't use one because you can't heat it up at the end of the rest (I havnt read anywhere that this is necessary.) She also advised not to use one because her friend brewed a batch and it ended up tasting like bubblegum.
Can anyone shed some light on any of this? Seems like everyone has had good success with their mlts, so her information caught me by surprise.

Paul, the bubble gum flavor could be coming from the fermentation stage. If you don't hit that all magical 68 F, then you are going to notice other flavors in the beer. In my experience when I just left the beer in the basement and didn't pay attention to temp I got banana/bubble gum flavor. Come to find out my fermentation was hitting 72F-74F.

Now, I am noticing that these coolers are not holding a solid 154F temp throughout the mash. As others have stated the bottom of the mash will be significantly cooler than the top. What that does to the end product is give it a dry/alcohol burn finish. In my case, I have hit my SG, but since the mash happened at a much lower temp there is more fermentable sugar for the yeast to go after.

I am embarking on an experiment to try and "fix" this issue. I will keep the forum updated on my findings.

 

[PaulTheGhost]

Paul, the bubble gum flavor could be coming from the fermentation stage. If you don't hit that all magical 68 F, then you are going to notice other flavors in the beer. In my experience when I just left the beer in the basement and didn't pay attention to temp I got banana/bubble gum flavor. Come to find out my fermentation was hitting 72F-74F.

Now, I am noticing that these coolers are not holding a solid 154F temp throughout the mash. As others have stated the bottom of the mash will be significantly cooler than the top.

I am embarking on an experiment to try and "fix" this issue. I will keep the forum updated on my findings.

I ferment in my closet, at about 65* on average (anywhere from 62*-68*), never above that. However, it's winter in nor cal right now so once spring starts heating things up I guess I'll have to figure out some way to keep it cooler.

Would it be acceptable to mash at say... 160* (2* above what is the normal max) and stir two or three times throughout the hour (with an insulated lid) to maintain temp of about 154, or would that release too much dextrin (depending on the style of brew)?

 

[Quaffer]

Sigh....That is what I feared. Since I don't have a large enough mash kettle, I may be forced into the RIMS world.

Of course I will have to test this out with about 6 gallons of water in my 10 gallon mash tun. I would lean towards how your mash tun is performing though.

The 10 gallon cooler has smaller surface area to volume ratio so it should perform better than the 5 gallon one.

One thought I had to try to combat this issue was to change out my tube with stainless steal mesh braiding for copper tubing with the stainless steal mesh braiding. Then, I could insert a paint stirring paddle through the lid and operate with a drill at a very low speed. My thought is that this would keep the temp mixed and stabilized throughout the mash.

Thoughts anyone?

I believe this is what some professional breweries do. They have paddles that almost scrape the bottom of the mash tun to agitate the mash and spread the heat.

I was considering for a while to make a direct fired MLT keggle, using a motor to spin a shaft with paddles near the bottom, firing the burner occasionally to maintain temperature. I decided it was too complicated (much work) for me to construct so I put it on ice, but it is in no way out of reach for a handy person to do. Even without added heat it would be an improvement over the static cooler.

 

[Quaffer]

I need to add that I always fill the MLT to the very top, I tweak the recipe until it comes out that way. This improves heat retention because it has the maximum amount of hot mash to help maintain temperature. I would do the same with the larger cooler, but now that I am going RIMS it does not matter so much.

 

[AussieBrewerInColorado]

So I went to my lhbs today...
I talked with one of the more knowledgeable staff members about using a ten gallon cooler as my mlt and she recommended not to use one. She said they're not food grade (not what the description of the cooler says) and that you shouldn't use one because you can't heat it up at the end of the rest (I havnt read anywhere that this is necessary.) She also advised not to use one because her friend brewed a batch and it ended up tasting like bubblegum.
Can anyone shed some light on any of this? Seems like everyone has had good success with their mlts, so her information caught me by surprise.

Tons of people use these including myself. Each to their own, i think they're great, keep temps awesomely and with batch sparging, I don't need to heat anyway. I find it hard to believe they are not food grade too.

 

[camus]

The 10 gallon cooler has smaller surface area to volume ratio so it should perform better than the 5 gallon one.

This is true but for a given volume up wort, you would be better off with the a smaller cooler, the greatest heat loss is going to be at the area of the valve, the bottom of the cooler and the top. By going with a larger tun you will be increasing the 2 of 3 areas of greatest loss. This assumes the 10gal is of greater circumference. Also, the headspace has just been increased. Honestly I don't know if you will see much of a difference.

FWIW, I see about a 1 to 1.5 degree drop with mine, with about .5 degree variance with stirring, this is at about 65 degrees ambient.

 

[billf2112]

Just adding a comment to keep this easy to get too.

BTW my LHBS has these pre-built for $120 with Blichmann parts.

 

[Quaffer]

This is true but for a given volume up wort, you would be better off with the a smaller cooler, the greatest heat loss is going to be at the area of the valve, the bottom of the cooler and the top. By going with a larger tun you will be increasing the 2 of 3 areas of greatest loss. This assumes the 10gal is of greater circumference. Also, the headspace has just been increased. Honestly I don't know if you will see much of a difference.

FWIW, I see about a 1 to 1.5 degree drop with mine, with about .5 degree variance with stirring, this is at about 65 degrees ambient.

It is best to use the smallest mash tun that will hold the mash, agreed 100%. Use the 10 gallon tun only for 10 gallon batches.

I guess the lid will be the area of greatest heat loss, being large and not insulated. Some inject it with foam to improve it, but I have not. That might shave a degree off my heat loss.

 

[rexbanner]

I made this design and it's been a ****ing nightmare. First, my SS braid collapsed immediately on the first batch I brewed with it. I lost a few gravity points but otherwise still managed to drain most of the wort.

So before my batch today, I bought a new SS braid, removed the nylon tube, put a bunch of holes in it, and reinserted it. I could barely get the wort to flow. So I dumped my mash into a pot, took the tun apart, enlarged the holes in the nylon tube, and reinserted it and put everything back together. This time I could get a trickle of wort, which stops after 30 seconds.

Basically, the SS braid collapses around the barbed connection. The barb will not fit inside the nylon tube.

How the hell did anyone ever get this to work just using a braid?

P.S. My braid is SS. 16x1/2'' OD. 3/8''ID.

 

[klyph]

What's the diameter and length of your braid?

 

[camus]

It is best to use the smallest mash tun that will hold the mash, agreed 100%. Use the 10 gallon tun only for 10 gallon batches.

I guess the lid will be the area of greatest heat loss, being large and not insulated. Some inject it with foam to improve it, but I have not. That might shave a degree off my heat loss.

I feel compelled to follow up, I just did a 1.5 qt/lb mash and lost heat gangbusters. Previously I had been doing 1.25 max, anyway I lost about 4 degrees over 90, just FYI.

 

[schreck]

Never had a problem with regards to off flavors from the igloo's. Im sure if anyone had problems, they would have been addressed a long time ago, especially with the large number of home brewers who rely on coolers for mash tuns.

Here are a few modifications i remember reading about on thi thread and similar ones (buried somewhere in the 153 pgs and counting):
- always preheat the cooler (i use simmering/near boiling water).
- The lid is hollow. Fill it with spray insulation foam.
- cover/wrap cooler with blanket/towels.
- use an electric water heating element to maintain temps in the mash.

I have had much success with filling the lid with foam and preheating. I usually only see a 2-3 degree temp drop during a 60min mash.

Another good tip i read:
If you are doing mini mash, or have smaller grain bills, go ahead and cut a layer of foam insulation measured to the diameter of the cooler (or dimensions of the 10gal cooler), and rest it just above the grain bed, thereby reducing the empty space.

 

[spookman]

The only stainless steel supply hose I was able to find was a 3/8ths x 1/2in FIP 12" hose. I want to make sure if this will work or not before I go ahead and cut it.

 

[dropitlikesitshot]

@rexbanner: I am building this and having my own challenges, but to address your collapsing braid i read a post where a person used copper wire 10-12 gauge and coiled it. Then elongated the coil and inserted in the braid. That may stop the braid from collapsing. I also just read on another DYI post where a person used a SS spring and inserted into the braid. Finally after reading your post I might just buy a false bottom.

 

[rexbanner]

@rexbanner: I am building this and having my own challenges, but to address your collapsing braid i read a post where a person used copper wire 10-12 gauge and coiled it. Then elongated the coil and inserted in the braid. That may stop the braid from collapsing. I also just read on another DYI post where a person used a SS spring and inserted into the braid. Finally after reading your post I might just buy a false bottom.

I would just go with a false bottom. I'm about to order one.