Most of the Igloo cooler systems are overpriced, IMHO. Check out Denny’s site for advice on building a cheap and easy mashtun http://hbd.org/cascade/dennybrew/
A rectangular cooler is a lot easier to use than a round one, in my experience.
+1! I got my rectangle Rubbermaid cooler on Craigslist for $10 and built the mash tun. Lots of videos online on how to build it. If I were to do it again, I would probably go the easier/ less $$ route like Denny’s instead of going with a ball valve.
+1 to the rectangular 70 qt Extreme ( and if you want good conversion you’ll get the blue one !). I used the round Igloo for years when I fly sparged, and I love the Extreme for batch sparging so much better. Dennybrew all the way !
I use an Igloo Cube with a copper manifold system. The drain unscrews and my ball valve fit right in. I think it’s 60 qt. I have made 10 gallons of 1.070 or so beer in it a few times. It was full but did the trick. 70 qt would probably be ideal for size. I like my cube because I had bought it several years ago but rarely used it because it doesn’t fit in the trunk of the car. So it wasn’t any extra cost. I don’t lose and temperature over an hour either. Just make sure you buy a blue cooler.
I use a forty quart white rectangular (marine) igloo cooler and do 5 gallon batches with it. It holds easily 25 pounds of grain with strike water, but if you want a thinner mash or do bigger beers a lot, the 70 can handle pretty much whatever you need and with batch sparging, you simply sparge a second or third time, if necessary, for a monster grain bill. If you are doing a lot of big 10 gallon batches, then consider a bigger one yet, I suppose, but then I go to my 3 keg system for that kinda batch.
I just spent some quality time looking at cooler options. Seems a lot of the Cube styles have a beveled edge where the drain goes, I think that would mess up draining things. I ended up buying a 48qt Igloo Marine rectangular cooler, it has a normal drain position and an indented area inside so the braid will sit low.
I alreay have a 5gal round cooler, a 60qt Extreme and a 100qt Extreme. I mostly use the 5gal cooler but will be using the 48qt for 5gal batches.
Also recently scored a new 10gal pot, so I have 3gal,couple of 5gal, 8gal 10gal, and 20gal. I’m about covered now.