First Time Mashing in a Cooler Question

[dsaavedra]

I'm planning on mashing in a cooler for my next brew because I have been having trouble holding temp when mashing in my kettle (BIAB).

I am brewing a one gallon batch and plan on thoroughly cleaning and using one of the coolers I have out in the garage (I will invest in a dedicated cooler MLT once I get the hang of AG brewing).

Here is my question: I am planning on having 3 gallons pre-boil. I can either mash in a 2 gallon cooler (full to the brim) and then sparge with the remaining gallon, or I can mash in a 7 gallon cooler with the full volume of my brewing water but the cooler will only be half full.

Would it be better to have my mash tun full to the brim and sparge to reach my final volume (never sparged before) or would it be better to do a full volume mash/no sparge in a cooler that will only be halfway full?

In my head I am thinking that using the smaller cooler will lead to better temperature retention, but the sparge seems scary and like it is one more step for me to screw up (even though I know it is just heating water to ~170 and adding it to my grains after I drain the wort out). Using the larger cooler seems attractive because I can just do a full volume mash like I am used to, I am just worried about heat loss due to all the headspace.

 

[TheHappyHopper]

I would use the smaller cooler due mostly to the fact that a larger cooler is going to soak up a lot more heat from the mash and sparge water. Of course, if you pour in hot water to preheat the larger cooler, that may not be an issue.

Personally I use a 2 gallon cooler for all of my batches - I do 5 gallon partial mashes, so I can fit about 5 pounds of grain + 1.5 to 2 gallons of water. I mash with about 1.25 quarts per pound (a little over 1.5 gallons), and then sparge twice with another 1.5 gallons each time. I end up with just shy of 4 gallons of wort when the sparging is done and I get very high efficiency. Since you are only doing a 1 gallon batch you could adjust that to fit your needs, but I think the 2 gallon cooler would be perfect.

 

[dsaavedra]

I was kind of leaning towards using the 2 gallon cooler as well.

My game plan is to line the cooler with my BIAB bag, mash with two gallons of water, drain the cooler (the two gallon cooler has a spout built in), pour in the remaining gallon of 170 degree water, stir it, let it settle for a minute (or maybe not?), and drain that to collect my 3 gallons of wort.

Does this seem like a decent way to go about it?

 

[petey401]

Yes stir in your "sparse"water and let sit 10 minutes


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[petey401]

Oops you're 1 gallon of sparge water


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[OaklandHills]

I mash in a 10 gallon Rubbermaid cooler now. I brew different size batches of beer (3 to 6 gals) so there is no simple formula for temperature control. That said, I always pre-heat the mash tun (cooler) by adding water hotter than my calculated dough-in temp. I put the hot water in the cooler, monitor the temp until the water/cooler temp is about right, then add the grains. By trial and error, I've found that the mash tun needs to be about 4 degrees warmer than what my calculator says my dough-in temp should be. I think that's because the cooler absorbs some more heat even after I pre-heat it. I've gotten to where I hit my initial mash temperature target pretty often. I'd recommend you use the larger cooler as it will be more flexible for higher gravity beers or different size batches of beer. You just have to figure out the geometry/heat loss formula for your particular setup.

 

[dsaavedra]

I mash in a 10 gallon Rubbermaid cooler now. I brew different size batches of beer (3 to 6 gals) so there is no simple formula for temperature control. That said, I always pre-heat the mash tun (cooler) by adding water hotter than my calculated dough-in temp. I put the hot water in the cooler, monitor the temp until the water/cooler temp is about right, then add the grains. By trial and error, I've found that the mash tun needs to be about 4 degrees warmer than what my calculator says my dough-in temp should be. I think that's because the cooler absorbs some more heat even after I pre-heat it. I've gotten to where I hit my initial mash temperature target pretty often. I'd recommend you use the larger cooler as it will be more flexible for higher gravity beers or different size batches of beer. You just have to figure out the geometry/heat loss formula for your particular setup.

I intend to get a 10 gallon rubbermaid cooler and do it up with a ball valve and braid hose and everything. But this is just a little 1 gallon batch while I am still working the kinks out of my AG brewing, so I'm just looking to use whatever I have out in the garage that will hold heat better than my kettle with a blanket wrapped around it.

I was definitely going to preheat the cooler, probably heat my water 5 or 10 degrees above what the strike temp is then add it to the cooler and let it sit for a few minutes then open it up and stir until it cools down to my strike temp.

Now I just have to figure out how to get the musty "cooler" smell out of the cooler - it is pretty old and has been sitting around the garage for a long time. I'm thinking a long soak in oxy clean and a good scrubbing with vinegar (maybe baking soda too) should help.

 

[Nagorg]

Drape a blanket over the top of the cooler. It works wonders!

 

[dsaavedra]

Drape a blanket over the top of the cooler. It works wonders!

Good call, I will remember to do this.