mash tun losing temperature

[Dgonza9]

I added a thermometer to my mash tun and then tested it by putting water in it at about 118 degrees (that's what my faucet temp is). The temperature dropped by about 1.5 degrees in half an hour... so about 3 degrees in an hour. my cooler is just a simple coleman cooler, not an extreme or anything.

If I want to mash at 152, should I try to hit 154 or something with my strike water? Is my cooler a piece of crappola and should I get another one?

Thanks for the help. Cheers.

 

[Benjibbad]

did you pre-heat your MLT? Your MLT will absorb some heat and the ability for it to maintain that heat will be dependent on a variety of environmental conditions. If it was just water 3 degrees isn't bad your mash will retain heat a bit better due to the consistency. Normally in the summer here in FL I shoot for 4 degrees above mash temp and on cold winter days I aim for 10. Shounds like you will be fine.

 

[RandomSF]

It dropped 1.5 degrees in a half hour, but one point doesn't make a trend. It is possible that the water temp dropped as the tun was heated by the water and that the second half hour would find little additional drop. That's a typical report on this forum and my own experience, too. I can't say what your situation is. You might want to try a longer test, say 1.5 hours, with temperature readings every 30 minutes.

 

[Dgonza9]

did you pre-heat your MLT? Your MLT will absorb some heat and the ability for it to maintain that heat will be dependent on a variety of environmental conditions. If it was just water 3 degrees isn't bad your mash will retain heat a bit better due to the consistency. Normally in the summer here in FL I shoot for 4 degrees above mash temp and on cold winter days I aim for 10. Shounds like you will be fine.

So I should aim for the initial strike water to get the mash four degrees hotter than optimal?

 

[OHIOSTEVE]

So I should aim for the initial strike water to get the mash four degrees hotter than optimal?

preheat the mash tun with water...then pour that out and pour in your 118 degree water while the mash tun is still hot. That will stop the cooler itself from "sucking the heat" out of the water. I bet you will see it hold temp better.

 

[Professor Frink]

preheat the mash tun with water...then pour that out and pour in your 118 degree water while the mash tun is still hot. That will stop the cooler itself from "sucking the heat" out of the water. I bet you will see it hold temp better.

I used to do this, but I found it easier to just put the water in at about 10 degrees above strike temp, then wait a couple minutes until the water gets to strike temp. Every cooler needs a different amount for preheating, but you'll figure yours out.

 

[Benjibbad]

So I should aim for the initial strike water to get the mash four degrees hotter than optimal?

Your initial strike water should be hotter than your mash temp. Your MLT will absorb some of the heat and adding your grains will bring down the temp as well. Each environment is different and you will need to figure out how much to adjust your temps for your given area. What works for me here in FL may not work for you in IL.

 

[rico567]

The OP doesn't provide some facts:

1) is the entire cooler insulated, including the lid? My Rubbermaid / HD 10 gal. cylindrical cooler had insulated walls but the lid was hollow. Even though I was throwing a furniture pad over it during the mash, I was losing 4-5F temperature during an hour mash. I insulated it by drilling some holes in the lower edge of the lid and injecting that "Great Stuff' insulation. Now I lose 1 degree F or less during an hour mash.

2) is preheating being done? I preheat using 3 gal. of 170F water for an hour.

IMHO, these are the crucial things to enable a cooler-type MLT to hold temperature well.

 

[Got Trub?]

3 degrees in an hour I wouldn't worry about. You could throw a blanket or towel on top to help hold in the heat a little more if you want. Like PF I stopped preheating and just compensate with a slightly higher strike temperature. By the time I have finished stirring the mash for a good 2-3 minutes everything has stabilized and I lose about 3F in an hour. The most important thing in mashing is consistency, your 152 and my 152 will not produce an identical wort. Over time you will learn to tweak your mash temperature in the direction that produces the beer the way you like it. For instance say a bitter recipe calls for a mash temp of 154 and the FG is 1.010. You do this and find that your FG is 1.013 so you lower your mash temp to 152 and now hit the targeted FG.

GT

 

[OHIOSTEVE]

I used to do this, but I found it easier to just put the water in at about 10 degrees above strike temp, then wait a couple minutes until the water gets to strike temp. Every cooler needs a different amount for preheating, but you'll figure yours out.

that is what I do.. I was just talkin about to do a test on heat loss. I generally heat up to 10 degrees or so above then stir until I hit my strike water temp and dump in the grains. It is hot enough right now that I juat set the mash tun in the sun for an hour.. Hardly lose anything.

 

[Dgonza9]

Brewed yesterday for the first time with my new mash tun. I put a winter coat over the top, lost maybe a degree and a half over the hour mash.

Plus, I could always recirculate and add heat now that I have a pump. I found that aspect of my new brew rig very satisfying.

 

[ZWood15]

I say use a can of "Great Stuff" and insulate the top, a quick and easy $5 fix

 

[Starderup]

preheat the mash tun with water...then pour that out and pour in your 118 degree water while the mash tun is still hot. That will stop the cooler itself from "sucking the heat" out of the water. I bet you will see it hold temp better.

+1
Never had to do anything beyond this. Try it. I bet your temp drop problem is solved.