smaller cooler?

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thomasben

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I have a 70 qt extreme cooler. Same brand a lot of brewers use and was wondering if I'd benefit from holding temperature and getting higher efficiency with a smaller cooler. My set up is designed for more higher gravity beers. I get about 72% everytime but lose 5-6 degrees during my 90 MIN mash. Even with the cooler wrapped in blankets. The corners even drop more
 
I have a 48 qt cooler and when I do 5 gallon batches I lose about 2 degrees in 60 minutes. With 10 gallon batches and the cooler as full as I can get it I lose 0 degrees in 60 minutes. So yes, I would say you would benefit from less open space. Get a smaller cooler or make bigger batches.
 
The dead space will only affect the temperature if you open the lid during the mash. The temp will stabilize (lose maybe 1 degree to do this) and after that, it should stay the same. I've never had problems with a 60 qt cooler for my 5 gallon batches. I just set it and leave it and lose at most 1 degree
 
Do you pre-heat your cooler? Being that much larger than your mash, I would think that could be a problem if you don't
 
If you haven't already, try running aluminum foil over the edges of the cooler before you close the lid and wrap everything in blankets. Hot mash has a very low emissivity meaning it readily loses heat via radiation to the cooler lid. If the lid's surface is aluminum rather than plastic a massive portion (around 95%) of that energy is radiated back to the mash which readily takes it back up due to its low emissivity. It also has the added benefit of decreasing convective losses since these picnic coolers lack gaskets (that would be another way to boost your heat retention btw).
 
I've always preheated but I'm wondering if I'm using hot enough water or even enough water for that matter?....how much water would you guys use to preheat a 70qt mash tun. Sometimes I use hot faucet water or like.130-150 degree. Maybe half full
 
I've found near boiling water works the best in my cooler. I throw in about a gallon, slosh it around and let it sit for a few minutes.
 
I use a 10 gallon round cooler for MLT and always preheat. I bring my HLT water up to 185-190. I preheat using the correct amount of mash water with the lid on the cooler. Let it sit for about 15 minutes, then open the lid, check temp, add grains at about 175 to 180 works for me, but a tall round mlt heats up easier because heat rises more uniformily.
 
Sweet! It has always worked perfectly for me too. The brew days on which I forget the Al foil for whatever reason I tend to lose a few degrees. When I remember I don't lose anything measurable.
 
I have a 10 gallon rubbermaid cooler. I preheat it with water out of my tap as hot as I can get it and a sprayer. I have checked my temps two or three times during the mash and I typically don't lose more than 1 degree in a 5 gallon batch.
 
Why not just add very hot water and let it sit till it falls to your strike temps? Is there any difference between you preheat water and your strike water?
 
Why not just add very hot water and let it sit till it falls to your strike temps? Is there any difference between you preheat water and your strike water?

For me, no. I start with 180-185* strike water, fill tun, let sit for at least 10-15 minutes, then stir down to above strike temp, dough-in, stir down a few degrees to mash temp, cover.
 
If you haven't already, try running aluminum foil over the edges of the cooler before you close the lid and wrap everything in blankets. Hot mash has a very low emissivity meaning it readily loses heat via radiation to the cooler lid. If the lid's surface is aluminum rather than plastic a massive portion (around 95%) of that energy is radiated back to the mash which readily takes it back up due to its low emissivity. It also has the added benefit of decreasing convective losses since these picnic coolers lack gaskets (that would be another way to boost your heat retention btw).


Also worth stating that the cooler lids are often just hollow plastic. Some people use expanding urethane foam ("great stuff" - cracks and gaps version) to insulate them.

I keep meaning to try that, but haven't gotten around to it yet.
 
Some other members have chimed-in that it's difficult to get the foam to actually expand from just a few entry points drilled in the lid. I'm thinking cutting the top layer off of the lid, filling with foam, then replacing/caulking the lid back together is a possibility...but I use blankets and last brew might have lost 1.5* over 65 minutes.
 
tre9er said:
Some other members have chimed-in that it's difficult to get the foam to actually expand from just a few entry points drilled in the lid. I'm thinking cutting the top layer off of the lid, filling with foam, then replacing/caulking the lid back together is a possibility...but I use blankets and last brew might have lost 1.5* over 65 minutes.

*shrug* the foam comes through a long nozzle. Distribution might be tricky i guess.
 
Considering that some brewers only do 20 minute mashes and swear by their conversion...I wonder how big of a deal it is to lose a degree or two over 60 minutes...
 
Some other members have chimed-in that it's difficult to get the foam to actually expand from just a few entry points drilled in the lid. I'm thinking cutting the top layer off of the lid, filling with foam, then replacing/caulking the lid back together is a possibility...but I use blankets and last brew might have lost 1.5* over 65 minutes.

I tried the foam - Great Stuff for Windows and Doors - it expanded inititally, then collapsed back into a liquid - ended up being useless.
 
Also worth stating that the cooler lids are often just hollow plastic. Some people use expanding urethane foam ("great stuff" - cracks and gaps version) to insulate them.

I keep meaning to try that, but haven't gotten around to it yet.

Yup, I did this too right from the word go. I had no trouble getting the Great Stuff to fill my whole lid. Every little bit of heat retention helps in my book!
 
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