Stopping Mash Tun Temp Loss

[chode720]

I am currently using a 48 qt (dont know the brand) cooler as my mash tun. I bought it to have enough room to do big beer and eventually some 10 gallon batches. Right now I am only doing 5 gallon batches and there is a lot of room between the mash and the top of the cooler.

Last batch, my temp started at 150.7 and dropped less than a degree during the whole 60 min mash. I stirred several times during the first 5 minutes or so to prevent hot spots and got a pretty even reading throught out mash.

Before I did my mash out, I decided to give the mash 1 more good stir and the temp dropped to almost 144 degrees.

I figure it dropped so much because the water on top cooled a lot during the 60 minutes and my question is, is there any way I can prevent this? I have seen some threads about people putting cookie sheets or tin foil in their tun as insulation, but I searched and couldnt find anything.

I'm wondering what other people use and success they had.


Thanks

 

[JMSetzler]

Three thicknesses of 1/2" pink foam insulation board from Home Depot. Mash temp drops less than 1 degree over the course of an hour...

 

[bendavanza]

HMM I may have to make a round one for my smaller batches

 

[Schlenkerla]

Three thicknesses of 1/2" pink foam insulation board from Home Depot. Mash temp drops less than 1 degree over the course of an hour...

I think this is a real good idea (one above).

I use a sleeping bag still rolled up and I set it on top. Seat cushions work well to.

One other idea; A Trash bag loaded full of loose wal-mart bags. Just jamb one large bag full. Then tie it closed. Drop it in your cooler.

I have three mash tuns; 12 gallon(48qrt), 5 gallon, 2 gallon.

Choozing the right one is what I do first. Small beers get the 5 and bigger ones get the 12. I use the 2 gallon for winter partial mashes.

 

[chode720]

Three thicknesses of 1/2" pink foam insulation board from Home Depot. Mash temp drops less than 1 degree over the course of an hour...

Nice, I'll have to make one of those. My cooler is rectangular so it shouldnt be hard at all. What did you use to seal them together. Is it just duct tape?

 

[kronik]

I hope that's food grade plastic...

 

[Bobby_M]

I'm convinced that most drastic temp loss stories are due to poor compensation for the heat the cooler itself will absorb. This can be fixed by striking 12F hotter than your normal strike temp, close the lid and let the cooler suck heat for a good 5 minutes prior to doughing in. I've used a 48qt cooler and only lost 2F in cold ambient temps. Your headspace may lose heat quickly if there's a really poor air seal at the lid joint.

 

[Revvy]

I'm convinced that most drastic temp loss stories are due to poor compensation for the heat the cooler itself will absorb. This can be fixed by striking 12F hotter than your normal strike temp, close the lid and let the cooler suck heat for a good 5 minutes prior to doughing in. I've used a 48qt cooler and only lost 2F in cold ambient temps. Your headspace may lose heat quickly if there's a really poor air seal at the lid joint.

Oh this is a cool idea....I usually pre heat my cooler with a couple of gallons of hot tap water....but this sounds overall more practical, lest wasteful, and just plain good sense.

 

[JMSetzler]

I made a smaller round one for my 5 gallon MLT also. I just haven't bothered to photograph it yet since I haven't used it yet. I'm sure the plastic wrap I made is NOT food grade. It's just a really heavy lawn and garden black trash bag.

 

[bob1852]

I'm convinced that most drastic temp loss stories are due to poor compensation for the heat the cooler itself will absorb. This can be fixed by striking 12F hotter than your normal strike temp, close the lid and let the cooler suck heat for a good 5 minutes prior to doughing in. I've used a 48qt cooler and only lost 2F in cold ambient temps. Your headspace may lose heat quickly if there's a really poor air seal at the lid joint.

+1 -- this winter I had 0F loss in a 60 minute mash in a garage where the ambient temp was about 48*F.

I struck in at 183*F, 5 minutes later doughed-in at 173*F. 5 minutes later was at 155*F and 55 minutes later was still at 155*F.

Then again, I have a Coleman X-reme cooler, and I think that really helps (the one's that advertise they'll hold ice for five days in 90*F air temps)

I also tend to overshoot the stike water temp by several degrees; I'll let the cooler absorb the heat for 5-minutes, and then if it's too hot still, I'll leave the lid open until I'm at my dough-in temp

 

[Schlenkerla]

I'm convinced that most drastic temp loss stories are due to poor compensation for the heat the cooler itself will absorb. This can be fixed by striking 12F hotter than your normal strike temp, close the lid and let the cooler suck heat for a good 5 minutes prior to doughing in. I've used a 48qt cooler and only lost 2F in cold ambient temps. Your headspace may lose heat quickly if there's a really poor air seal at the lid joint.

I totally forgot about this. I boil water. Add this to the mash tun. Let it sit 5 minutes then drain to the HLT where its at a near perfect temp at sparge time. 175-180F

 

[wilserbrewer]

I'm convinced that most drastic temp loss stories are due to poor compensation for the heat the cooler itself will absorb. This can be fixed by striking 12F hotter than your normal strike temp, close the lid and let the cooler suck heat for a good 5 minutes prior to doughing in. I've used a 48qt cooler and only lost 2F in cold ambient temps. Your headspace may lose heat quickly if there's a really poor air seal at the lid joint.

Yup, +1 Bobby.

I might also add that it is critical to measure the mash temp once it has stabilized, meaning a good 5+ minutes or so after doughing in. If you measure the mash temp too soon, the grain will still be absorbing the heat of the strike water.

I heat my strike water in place w/ an elecric element and always overshoot strike temp. and let it cool down b'fore mashing in.

 

[adamjab19]

Has anyone seen a thread where someone talks about using ziplock bags filled with t-shirts as insulation instead of the pink board?

 

[springer]

if you are worried about being food safe you could use tin foil over the pink board or a large turkey oven bag .

 

[IrregularPulse]

I also add my strike water hotter than needed and let it preheat for 5-10 minutes, then open the lid to let it cool to strike temp if needed, or dough if I calculated right.

 

[chode720]

I also add my strike water hotter than needed and let it preheat for 5-10 minutes, then open the lid to let it cool to strike temp if needed, or dough if I calculated right.

Based on the suggestions from here, this is what I decided to do. I heat my strike water about 10 degrees hotter than and I need and just add it in. However, it usually takes my cooler about 20 min to absorb all the heat and drop enough. But thats okay, it keeps my mash temp pretty consistent throughout the whole conversion

 

[Schlenkerla]

Has anyone seen a thread where someone talks about using ziplock bags filled with t-shirts as insulation instead of the pink board?

Try this.

• Take plastic wal-mart bags and stuff them full of the plastic bags. Tie them closed. Drop them on top of the mash.

Or...

• Ping pong balls. Buy two-four boxes or whatever it takes to make one complete layer plus a few extra. Drop them onto the mash. They act as a blanket and as a diffuser during recirculation. This is a common heat retaining method in plating operations. It works really good!

McMaster-Carr You will find this in this particular link.

Create a floating blanket on the surface of chemical and processing tanks to slow evaporation, cut heat loss, and reduce pollution by containing fumes. Ball diameter should be larger than the inlet, outlet, and overflow pipe diameters of your tank.

 

[adamjab19]

Thank you for the responses!

Preheating the tun worked great this time. My first time through I don't think I had it hot enough as well enough water in there.

 

[bendavanza]

After insulating the lif of my 10g round Gott cooler I get 1˚ F loss over 1 hour. I take some strike water and splash the insides as I'm approaching strike temp, close the lid, when I hit strike temp I dump out this water (could use a rinse, right?) and fill, close the lid, wait 5-10 minutes, check temp, dough in etc. I shoot for HLT 10˚ F over strike temp. When I dough in I am usually about 3˚ over mash temp, but stirring for a while gets me on the money, or I drop about 5 ice cubes per degree I need to lose. My new mash paddle is all copper so I know it's acting a bit like a heat sink.

 

[dfohio]

Preheating the mash tun is a necessity. However, I do notice a lot of heat transfer from the valve itself, acting as a kind of heat sink. I was only losing a degree in an hour, but putting a towel around the valve seems to help.

 

[Dcollins202]

where is the best place to take your temp reading in the mash?

 

[chefchris]

where is the best place to take your temp reading in the mash?

I always stir my mash up with the thermometer to get a good reading on it.