Losing 4 -5 Degrees in an Hour-Long Mash

[MEPNew2Brew]

I have a 72 quart Coleman Xtreme that I use for a mash tun.

Typically, my brews have 13-17 lbs of grain. 1.25 quarts/gallon. I pre-heat the tun with 3 gallons of 190 degree water. I am losing about 4 degrees F in an hour-long mash. Outside temp. about 49 degrees, no wind.

Thermometer is solid - Thermapen; temperature checked recently.

I thought with an Xtreme, I shouldn't lose any more than one degree in an hour.

Is the tun just too big? It is not even half full when I mash about 13 pounds of grain? Is there something else I should try?

Any ideas/thoughts would be appreciated. I am somewhat disappointed that I bought a relatively expensive cooler to start with and it is not performing as I had expected.

While I wouldn't be happy, if I will get better performance, I could switch to a 10 gallon round Igloo or another cooler.

Thank you.

 

[shoshin]

I'd say your mash tun is waaaay too big for ~13# grain bills. Head space will kill your temperature, and the more head space, the more you will loose heat. Might not be practical, but I have 3 mash tuns for different grain bills: a 5 gal igloo that handles my 3 gallon batches and some of my 5 gallon batches, a 10 gallon rectangular that handles my 5 gallon big beers, and a 15 gallon rectangular that handles my 10 gallon batches. It is best to match the size of your mash tun to the size of your mash.

 

[shoshin]

There's a thread on here called 'This is how big your Mash Tun needs to be', check that out pronto

 

[ButcherBoy]

I had a similar problem with my large cooler, I got a big one and was loosing temp due to headspace. I had several scrap pieces of 2" foam insulation from my fermentation chamber project. So I cut them to fit my cooler, wrapped them with a ziplock freezer bag, and put them on top of the mash when I'm done stirring, close the lid and... Holds within a degree for the entire mash. Simple, low cost, problem solved!

 

[DrWill]

I have a 72 quart Coleman Xtreme that I use for a mash tun.

Typically, my brews have 13-17 lbs of grain. 1.25 quarts/gallon. I pre-heat the tun with 3 gallons of 190 degree water. I am losing about 4 degrees F in an hour-long mash. Outside temp. about 49 degrees, no wind.

Thermometer is solid - Thermapen; temperature checked recently.

I thought with an Xtreme, I shouldn't lose any more than one degree in an hour.

Is the tun just too big? It is not even half full when I mash about 13 pounds of grain? Is there something else I should try?

Any ideas/thoughts would be appreciated. I am somewhat disappointed that I bought a relatively expensive cooler to start with and it is not performing as I had expected.

While I wouldn't be happy, if I will get better performance, I could switch to a 10 gallon round Igloo or another cooler.

Thank you.

I wonder if preheating your mashtun would help with this. What do people think?

 

[brew_ny]

I have a 72 quart Coleman Xtreme that I use for a mash tun.

Typically, my brews have 13-17 lbs of grain. 1.25 quarts/gallon. I pre-heat the tun with 3 gallons of 190 degree water. I am losing about 4 degrees F in an hour-long mash. Outside temp. about 49 degrees, no wind.

Thermometer is solid - Thermapen; temperature checked recently.

I thought with an Xtreme, I shouldn't lose any more than one degree in an hour.

Is the tun just too big? It is not even half full when I mash about 13 pounds of grain? Is there something else I should try?

Any ideas/thoughts would be appreciated. I am somewhat disappointed that I bought a relatively expensive cooler to start with and it is not performing as I had expected.

While I wouldn't be happy, if I will get better performance, I could switch to a 10 gallon round Igloo or another cooler.

Thank you.

I agree too much head space I have the same cooler but do 21 pounds or more of grain and do not loss but a degree in an hour mash

here in new york and it is cold

all the best

S_M

 

[ButcherBoy]

Definitely preheat! I preheat my tun with about 1.5G of boiling water. I heat that water in a separate pot while the strike water is heating, when the small pot boils I add it to the tun and close the lid, when the strike water hits target temp I empty the preheat water and mash in. I usually overheat my strike water, then add the strike volume to the preheated tun, allow the strike volume to cool to the strike target temp, then add the grain.

Did that with my last three batches and hit my mash temp all three times. Before that I always ended up 5-8 degrees high or low, it was really getting frustrating, but with this technique I seem to have solved my mash temp problem.

 

[MEPNew2Brew]

Thanks all. It looks like the tun is just too big. Either get a smaller tun or some foam. I am leaning toward a 10 gallon Igloo cooler. More expensive than some foam, but it will allow me to avoid adding foam to the equipment list to keep track of, clean etc.

Dr. Will - thank you for your reply. I preheat with three gallons of 190 degree water.

 

[brew_ny]

Thanks all. It looks like the tun is just too big. Either get a smaller tun or some foam. I am leaning toward a 10 gallon Igloo cooler. More expensive than some foam, but it will allow me to avoid adding foam to the equipment list to keep track of, clean etc.

Dr. Will - thank you for your reply. I preheat with three gallons of 190 degree water.

or brew 10 gallon batches

 

[clarksc4]

I use the same cooler and do 5 gallons batches. I lose about 1-2 deg in an hour mash, even brewing outside in michigan during the winter. In colder months I do larger beers (coincidentally) that are around 18# grain bill so that might help a bit. Anyways, I heat my strike water to about 190 and put all of it in the cooler, close the lid, and let it sit for 2-3 minutes, or until it comes down to my actual strike temperature, then dough in
If you want help with heat loss you could cover cooler with some towels during mash or increase your water:grain ratio.

 

[LandoLincoln]

Thanks all. It looks like the tun is just too big. Either get a smaller tun or some foam. I am leaning toward a 10 gallon Igloo cooler. More expensive than some foam, but it will allow me to avoid adding foam to the equipment list to keep track of, clean etc.

Dr. Will - thank you for your reply. I preheat with three gallons of 190 degree water.

I add a layer of aluminum foil on top of the mash before closing the lid. I typically lose less than a degree in a 60 minute mash. Lots easier than having to clean foam insulation every time.

When I brew outside and it's cold out, I also throw a sleeping bag on top of the mash tun.

 

[SpeedYellow]

Alum foil is thermally invisible so that's not going to do much good.

 

[cjgenever]

Alum foil is thermally invisible so that's not going to do much good.

It's useless for conduction, but is the best for reflecting radiant. That is why it is adhered to insulation designed to be used with a dead air space. In combination with some poly-iso it can do wonders.

 

[SpeedYellow]

It's useless for conduction, but is the best for reflecting radiant. That is why it is adhered to insulation designed to be used with a dead air space. In combination with some poly-iso it can do wonders.

Yeah, agreed. I didn't mean to make a blanket statement bout about aluminum, just this idea of laying it on the mash.

 

[LandoLincoln]

Alum foil is thermally invisible so that's not going to do much good.

I'm telling you, it works great. I've tried it with and without, and there's a big difference.

 

[EarlyAmateurZymurgist]

Thanks all. It looks like the tun is just too big. Either get a smaller tun or some foam. I am leaning toward a 10 gallon Igloo cooler. More expensive than some foam, but it will allow me to avoid adding foam to the equipment list to keep track of, clean etc.

Dr. Will - thank you for your reply. I preheat with three gallons of 190 degree water.

You can get the industrial yellow version of the 10-gallon Igloo beverage cooler for $51.99 from Zoro Tools with free shipping. Zoro Tools is the retail arm of Grainger.

http://www.zorotools.com/g/Beverage Coolers and Accessories/00055135/

 

[ph0ngwh0ng]

Thanks all. It looks like the tun is just too big. Either get a smaller tun or some foam. I am leaning toward a 10 gallon Igloo cooler. More expensive than some foam, but it will allow me to avoid adding foam to the equipment list to keep track of, clean etc.

Dr. Will - thank you for your reply. I preheat with three gallons of 190 degree water.

Not too fast!!

No need for foam. Buy Reflectix bubble wrap. 1F loss on an hour long mash. Real easy to clean.

 

[cjgenever]

You can get the industrial yellow version of the 10-gallon Igloo beverage cooler for $51.99 from Zoro Tools with free shipping. Zoro Tools is the retail arm of Grainger.

http://www.zorotools.com/g/Beverage%20Coolers%20and%20Accessories/00055135/

Seen then@ Lowe's for about that.

 

[cjgenever]

Not too fast!!

No need for foam. Buy Reflectix bubble wrap. 1F loss on an hour long mash. Real easy to clean.

Yeah, that stuff is good. I set up a keggle system, but wanted a 5 gal option so I wrapped my primary fermenter in that reflective bubble wrap. I then wrapped some r-19 fiberglass in aluminum foil (for sanitary and cleaning) and wrapped it around the bucket. Sealed all seems with aluminum tape. Put aluminum foil over the top before putting the lid on. Covered the lid with r-19 and a winter coat...

1 degree or less drop over an hour. And it was all stuff I had@home. I was careful with the setup and breakdown so I can use it all indefinitely.

Btw, based on my first brew with over 14.5 lb of grain I would say it can handle up to 15 lbs

 

[william_shakes_beer]

Also, be sure your cooler lid is insulated. A lot aren't. If not, drill a hole in the top and fill with some touch-N-foam

 

[worthogg]

I have the same cooler (72 qt extreme) and also do 5 gal batches all the time. I'll add that insulating the top works wonders. I just use a couple of wool blankets I had laying around. Lose a degree or maybe two if its really freezing out. I got this cooler n particular for its versatility. I also do 10 gal batches and it's great for both. If you search around you'll see a lot of us use this cooler with great results. You shouldn't have to buy another IMO.

 

[dangerbrew]

The best advice I'd say, which contains a lot from what others have said that has been posted already but which I can confirm works great, regardless of the size of mash tun (tho excessive head space will hurt some) would be:

1. Always preheat the mash tun.

2. Use the Reflectix heat wrap. (my mash temps SUCKED before using this)

3. Get your mash in there and mixed as fast as possible.

4. Cover the top with foil or metal lid (I use a metal pizza tray myself for my keggle) or just the lid that came with your cooler if that's what you have.

5. Drape a bunch of towels or a sleeping bag over the top.

I do this every time, and open it up to stir about 2 or 3 times during the mash to make sure the temp is distributed evenly. Regularly, the most temp loss I ever suffer is 2 degrees F which isn't bad for a 60 min. mash.

 

[cjgenever]

Couldn't we use a couple layers of reflexive layed on top of the mash inside the tun? That would insulate against conduction, convection (if cut to fit well), and radiant. Combine that with good exterior insulation (isn't that the point of the xtreme series to begin with) and we should have a winning team!

 

[dangerbrew]

Couldn't we use a couple layers of reflexive layed on top of the mash inside the tun? That would insulate against conduction, convection (if cut to fit well), and radiant. Combine that with good exterior insulation (isn't that the point of the xtreme series to begin with) and we should have a winning team!

Yeah, that sounds like a pretty neat idea. Either lay it right on top of the mash itself or attach it to the bottom of the lid. If you try it, let me know how that works! Also, for the Reflectix on the outside, I did two layers on my keggle and it holds quite well.

 

[m3n00b]

Alum foil is thermally invisible so that's not going to do much good.

I'm telling you, it works great. I've tried it with and without, and there's a big difference.

Exactly. It's not about insulating...it's about reducing head space which will allow for less evaporation which causes most of your heat loss. It's the same concept as a solar blanket for swimming pools. It doesn't make the water heat up, it only stops evaporation which is the main reason pools stay cooler than the ambient air.

 

[NathPowe]

Another vote throwing some sort of insulation over your cooler. I use a few towels. Also, using a thinner mash will help quite a bit. I generally mash with ~1.75 qts/lb. This, in combination with the towels over the cooler, results in a loss of 1 degree over an hour - at most. YMMV. Enjoy the brew.

 

[SpeedYellow]

Couldn't we use a couple layers of reflexive layed on top of the mash inside the tun? That would insulate against conduction, convection (if cut to fit well), and radiant. Combine that with good exterior insulation (isn't that the point of the xtreme series to begin with) and we should have a winning team!

Heck no! Is the stuff food grade? No way would I put some random plastic in an acidic liquid food environment at 155 degrees. Sure you can do it and not die, but that doesn't make it wise.

 

[cjgenever]

Heck no! Is the stuff food grade? No way would I put some random plastic in an acidic liquid food environment at 155 degrees. Sure you can do it and not die, but that doesn't make it wise.

I would set it up so the stuff isn't floating in the wort as well as seal the "assembly"with foil, seams on the top with foil tape. The only thing that might touch the wort would be the aluminum. I would never put non food grade and temperature rated plastic in the wort. This should be obvious, but I Should not have assumed.

Btw, this stuff is faced on both sides with aluminum. Could probably just cut out long do the ends gold up the tun. Suppose it would depend on the width of the material.

 

[SpeedYellow]

I would set it up so the stuff isn't floating in the wort as well as seal the "assembly"with foil, seams on the top with foil tape. The only thing that might touch the wort would be the aluminum. I would never put non food grade and temperature rated plastic in the wort. This should be obvious, but I Should not have assumed.

Btw, this stuff is faced on both sides with aluminum. Could probably just cut out long do the ends gold up the tun. Suppose it would depend on the width of the material.

Oh, gotcha. I agree, and I've considered doings this same thing, since my Coleman max cooler has ledges and is tapered, I would be easy to float some type of foam board or whatnot a few inches above the mash. Not high on my priority list, though.

 

[dangerbrew]

Oh yeah, obviously you wouldn't want the insulation "itself" lying on the grains but you'd put something like sanitized foil between the two and I'd assume you'd be fine. I wouldn't want anything like that actually touching the mash.

Although I'd be more apt personally to just affix it to the bottom of the lid somehow which is something I might try and do in the near future...