Cooler heat loss

I converted a 48 qt. Coleman(non Extreme) cooler to a mash tun and I
tested it last night for temperature control. It did very poorly as the
water I put in at 156F went to 126F(!) in an hour. I believe the grain
will hold heat better, but I think I'm still loosing a lot of heat
through the poorly insulatated cover. I could feel the heat escaping
the whole time, even though I had a blanket on it.

Does anybody use this cooler? What do U do to keep the heat in? I'm
planning on buying one of those hot water heater foil insulators to wrap
around it. Any other suggestions? I might also put my brewbelt under
the insulation to keep it hot in there. it's funny that none of the websites I looked at put any more insulation on the cover and they seemed to work.

GReg

Run a test with pre-heating the tun. Boil some water, add it to the cooler, let it sit ten minutes. Drain and add your "mash" water (at 154). See how it holds then before worrying too much.

Well i did put some hot water in, but i didn't boil it. Regardless, it still looks like I'm losing alot of heat.

grnich said:

Well i did put some hot water in, but i didn't boil it. Regardless, it still looks like I'm losing alot of heat.

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But it is expected that you will lose heat if you put hot water into a cold cooler. You either need to pre-heat the cooler or put in water that is heated to a temperature ABOVE your mash temperature to compensate for the loss (the latter can be calculated fairly precisely). Here is a good suggestion from another post:

bandt9299 said:

There is a little program out there also it's called mashcalc.exe you put in your ratio and rest Temp and it will tell you how much water to mash in and @ what temp, this is the best program I've seen so far for hitting your mash temp, no warming up the tun just right on the money every time so far, I use Beersmith and its always 5 degrees lower, I'm curious how much this would affect the first rest Temp, anyways good luck, It's not hard at all.

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I usually bring the water up to about 10-15 degrees above the strike temp I need, pour it in the cooler, and wait for it to cool to the desired strike temp. This is more time- and fuel-efficient than pre-heating the cooler with water that will just get dumped out. (I believe it was Rich Brewer who pointed this out to me.)

cweston said:

I usually bring the water up to about 10-15 degrees above the strike temp I need, pour it in the cooler, and wait for it to cool to the desired strike temp. This is more time- and fuel-efficient than pre-heating the cooler with water that will just get dumped out. (I believe it was Rich Brewer who pointed this out to me.)

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Ah -- you didn't say this. I think your original post said that you started with 156 degree water (not 166 or 161). I understand now.

Try that foil-like insulation they use on water heaters. I bet that would help more than a blanket.

FlyGuy said:

Ah -- you didn't say this. I think your original post said that you started with 156 degree water (not 166 or 161). I understand now.

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Confusion alert! I'm not the originator of this thread. :rockin:

I use a beverage cooler with the screw on lid, I preheat the tun, I also run a calculation to determine strike temps. I lose about 1 degree per hour, I think that is pretty typical. You are right too, the more grist you have in there, the better it will insulate itself.

Brewpilot

I would also think that the mash would assist in holding the temperature. I've never done all-grain, but sugar (and I can only assume starch) holds heat very well - ever stick something sweet in a microwave? The grain itself would probably act as an insulant as well.

cweston said:

Confusion alert! I'm not the originator of this thread. :rockin:

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Oops -- end of the week -- too early in the day -- need coffee.... :cross:

cweston said:

I usually bring the water up to about 10-15 degrees above the strike temp I need, pour it in the cooler, and wait for it to cool to the desired strike temp. This is more time- and fuel-efficient than pre-heating the cooler with water that will just get dumped out. (I believe it was Rich Brewer who pointed this out to me.)

Click to expand...

I know that I *can* do it this way, I just prefer doing a full pre-heat-and-dump. Personal preference. You only need a small amount of hot water to preheat - since I mash in the kitchen, I'll use the water from the teakettle while my mash water heats next to it. The difference in efficiency, im my estimation, is negligible. The benefit to this approach, I think, is being able to more closely hit my mash temp with fewer adjustments. I know the heat loss from the tun is essentially zero, it's not a range of 10 - 15 degrees (with that range potentially varying based on the size of the mash, ambient temp, and other factors).

Okay, here's what I did. I heated some water to 170F in a pot. I poured the water into the cooler, waited until the water temp went down to 156, then closed the cover and wrapped with a blanket. I also put some hot water in before I did that to pre-heat it.

It took a couple of minutes to cool down to 156 before I closed the cover. I think the inside of the cooler was pretty hot, so I don't
think preheating is my problem. The fact that the cover is warm to the touch means it is definitely loosing alot of heat. I'll try the foil
insulation. Seems to work okay on my water heater.

grnich said:

Okay, he's what I did. I heated some water to 170F in a pot. I poured
the water into the cooler, waited until the water temp went down to 156,
then closed the cover and wrapped with a blanket. I also put some hot
water in before I did that to pre-heat it.

It took a couple of minutes to cool down to 156 before I closed the
cover. I think the inside of the cooler was pretty hot, so I don't
think preheating is my problem. The fact that the cover is warm to the
touch means it is definitely loosing alot of heat. I'll try the foil
insulation. Seems to work okay on my water heater.

Click to expand...

So you pre-heated and you over-heated. Yep, dat cooler don't hold da heat.

I am curious -- what type of Coleman cooler was it? (Must be an older one?) I was going to get a new one for bigger mashes, and I would like to avoid whatever you have!

Yeah, that doesn't sound good. I can't feel any heat escaping at all from the Xtreme.

Bummer, Id get a 10 gallon Rubbermaid beverage cooler, I have the 5 gallon and it is good for single infusions up to 13 lbs of grain, but that is it. If you want to do multiple infusions, you will need the 7 or 10 gallon. Trial and error, we are all just experimenting here.

Brewpilot

FlyGuy said:

So you pre-heated and you over-heated. Yep, dat cooler don't hold da heat.

I am curious -- what type of Coleman cooler was it? (Must be an older one?) I was going to get a new one for bigger mashes, and I would like to avoid whatever you have!

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Got it at Walmart. Didn't see any Extremes there or I would have gotten one. I have a feeling picnic coolers are not stocked well in arctic-like winters. LOL! It's the cheap looking blue one.

grnich said:

Got it at Walmart. Didn't see any Extremes there or I would have gotten one. I have a feeling picnic coolers are[n't] stocked well in arctic-like winters. LOL!

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No kidding -- I have been running all over town trying to find a new cooler here in Calgary. I have gone into a whole bunch of stores asking for a big ice cooler, and they (first look outside and) think your nuts! Then I lie and tell them "I need a big cooler to keep stuff outside without freezing" and then they go "Ahh" and run off to check the stockroom! (Still no luck here, though -- I could only find those cheap blue 48 qt coolers, which is probably what you have.)

It took a couple of minutes to cool down to 156 before I closed the cover. I think the inside of the cooler was pretty hot, so I don't think preheating is my problem. The fact that the cover is warm to the touch means it is definitely loosing alot of heat.

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grnich,

"Hot" is a relative term. Just because it felt hot to you doesn't mean it was adequately pre-heated. SWMBO's opinion of "hot" is lukewarm to me. Also, how much 170ºF water did you use to pre-heat? Obviously the less liquid you use, the more temperature stability problems you are going to have... especially in a 10 gallon cooler. If you want a semi accurate test, you're going to have to use the same amount of water you plan to use on brew day.

From your results (170ºF dropping to 156ºF in "minutes"), either your cooler was not properly preheated, or you didn't use enough liquid (or both). 170ºF liquid in my non-insulated metal brew kettle won't drop more than a few degreed in 5 minutes, let alone 14ºF! Before you spend a bunch of time on modifications, I would rethink your test methods.

jcchem, your point is well-taken. It wasn't a very accurate test because I didn't use the full amount of water, but the heat loss was real and would still lose a lot of heat with a full batch. I just wanted to test the insulating capabilities of the cooler. It proved to me that I need to keep the heat in better before I try it with real grain.

I'd still try the test again. Do a full pre-heating like I suggested, let it sit for ten or fifteen minutes, drain, then add three or four gallons at ~160. See how bad the cooler really is. Ideal would be if you had a digital probe thermometer that you could suspend in the water, so that you could see the temp change in real time.

I had a similar problem years ago with a cheap blue cooler I bought. I noticed the lid was hollow and un-insulated. I drilled a 1/2 inch hole in the back edge of the lid and poured it full of vermiculite, and sealed the hole with duct tape. Heat loss was greatly reduced. These are coolers, intended to keep things cool not hot, so the cheapo ones may have no insulation in the lid. I also wrapped my winter weight sleeping bag around it when I used it.

The space in the lid is empty by design... air is an excellent insulator.

What size and shape was the cooler? This is a factor in the heat loss

If you buy a chest cooler with base measuring 12x24 and one 12x12

Add three gallons of water into each:


Surface area in contact with the water: (bottom + four walls)


The 12x24 will have more heat loss than the 12x12.

I believe you could have the same effect if the base was smaller but the fill height
is high. Imagine if you filled a 3" PVC tube with 3 gallons of water.

I think the happy medium is that the cooler width & depth should equal water height.

On a separate thought....

I have worked with plating for a number years. We had this one trick to hold water at 210'F w/o much evaporation. Ping-Pong balls. Its phenominal how much a difference this makes.

http://www.mcmaster.com/

Search: Part no. 3748k31

One could to add about 15-20 of these ping-pong balls on top the mash water. You would want to preheat these too.

They should not get in the way of draining the mash or sparging.

Schlenkerla said:

On a separate thought....

I have worked with plating for a number years. We had this one trick to hold water at 210'F w/o much evaporation. Ping-Pong balls. Its phenominal how much a difference this makes.

http://www.mcmaster.com/

Search: Part no. 3748k31

One could to add about 15-20 of these ping-pong balls on top the mash water. You would want to preheat these too.

They should not get in the way of draining the mash or sparging.

Click to expand...

Cool, I can see it now...Ping Pong Porter, Big Ball Belgian, Double Ball DoppelBock...

This is the cooler I have. It is a 48qt Coleman, blue.



My first mash I lost about 5 degrees over an hour. This was without using a blanket. My last mash I used a heavy blanket on top of the cooler and I only lost 2 degrees over an hour. I do not pre-heat the cooler, but I do bring it inside the night prior to brewing, so it is about 72 degrees when I put the strike water in.

Schlenkerla said:

On a separate thought....

I have worked with plating for a number years. We had this one trick to hold water at 210'F w/o much evaporation. Ping-Pong balls. Its phenominal how much a difference this makes.

Click to expand...

Nice... it makes sense, acting like another lid. I'll have to try that!

I used a cheap 3 gallon cooler for PM. I built a box (with lid) from the blue sheets of insulation. Test run with no preheating and the water dropped 8 or 9* over 6.5 hours.

You could build the box large enough to clear the valve and have a piece you can pull off to access the valve and install the tubing.

boldone said:

This is the cooler I have. It is a 48qt Coleman, blue.

My first mash I lost about 5 degrees over an hour. This was without using a blanket. My last mash I used a heavy blanket on top of the cooler and I only lost 2 degrees over an hour. I do not pre-heat the cooler, but I do bring it inside the night prior to brewing, so it is about 72 degrees when I put the strike water in.

Click to expand...

That's the one I'm using. Maybe in a real mash it'll work out better if it worked okay for you. I just picked up some aerosol foam insulation at Home Depot. I'm going to drill a hole in the cover and fill it full of that. It can only help I'd think. I'll wrap it with a blanket as well.

I use a 10 gallon Igloo water cooler from Home Depot. I heat it up with a gallon of water at 170 degrees for about 10 minutes before mashing in. I've done 90 minutes for a Hefe and I don't lose a single degree. I do keep the lid on though.

......and a beer

People love to over think these types of things. I was having the same types of problems. I covered the top of my cheap uninsulated covered cooler with a towel that was folded over several times and greatly improved the heat retention of my rig.

stlbasementbrewer said:

People love to over think these types of things. I was having the same types of problems. I covered the top of my cheap uninsulated covered cooler with a towel that was folded over several times and greatly improved the heat retention of my rig.

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Great minds think alike, lol. I do this also.

stlbasementbrewer said:

People love to over think these types of things. I was having the same types of problems. I covered the top of my cheap uninsulated covered cooler with a towel that was folded over several times and greatly improved the heat retention of my rig.

Click to expand...

Yah, I know what you mean. Its the engineer in me. I'm trying to gear up for AG and I'm trying to figure out whether to use one of my current coolers or to go out an buy a 10 gallon one.

I have a 12 gallon Igloo cube another 12r like grnich's. Just wondering if SWMBO would stroke out if I modified one our coolers for AG duty.

If you are anything like me, you want to make the best choice for the $$ you have to spend. Not to mention its good to talk it out with the people who know what works best.

Schlenkerla said:

I have a 12 gallon Igloo cube another 12r like grnich's.

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Many users here have used the Igloo Ice Cube coolers with great success. I'd say the Igloo Ice Cube and the Coleman Xtreme are the two most popular coolers to convert on this forum, with the round Gott beverage coolers being the 3rd most popular. I was having a hell of a time locating round 10 gallon beverage coolers, so I opted for the Xtreme.

Greg75 - Thanks for the reply.

I will use my igloo cube and try to do what this guy Paul has done with his El Cheapo Mash Tun. It seems pretty easy.

http://cruisenews.net/brewing/infusion/page1.php

I'll save what I would have spent on a cooler. I have $50 bucks in Home Depot gift card to throw into getting some copper tubing for my wort chiller.

Schlenkerla said:

Greg75 - Thanks for the reply.

I will use my igloo cube and try to do what this guy Paul has done with his El Cheapo Mash Tun. It seems pretty easy.

http://cruisenews.net/brewing/infusion/page1.php

I'll save what I would have spent on a cooler. I have $50 bucks in Home Depot gift card to throw into getting some copper tubing for my wort chiller.

Click to expand...

I just bought an immersion chiller at LHBS. I was going to build one, until I realized how much copper is selling for right now. I built everything else, from the MLT, to converting my keg, etc. But, I decided just to spend the extra $10-15 and get an immersion chiller already built. It was kind of an impulse buy, but I know this one's built very well. Mine probably would have looked somewhat cheap compared to this one. Downside is, it's probably only big enough to cool five gallon boils, so if I ever go to ten gallon batches, I'll either have to get a bigger immersion chiller, or a CFC.

How about cutting a piece of styrofoam the same size and shape of the cooler to float on top of the mash? like the ping pong balls.? thinking inside the box!