BIAB in a cooler?

Going to be doing a mini mash tomorrow. About 5lb grain. I don't love the blanket not the oven method for holding temps. I do have in my possession a 10 gallon HD cooler which is waiting to one day become a false bottom tun. Can I heat my strike water in the BK, pour it into the cooler, tie off my grain bag and drop it in? Is there a reason the bag shouldn't sit on the bottom of the cooler? I can just pull the grain bag out after and drain it on a colander. That way I can hear some sparge water to dunk sparge in the kettle.

yes you can do it that way.. be aware of temperature drop when you put the water in the cooler...I would heat it a little higher and pour it in then check the temp and put the grains in... I would worry a little bit about the grain bag expanding enough to allow the grain real good contact with the water..... another option I might consider.. just dump the grains in the cooler....put the grain bag over the boil pot and after mashing just pour the mash from the cooler ino the pot...lift out the bag and let it drain....

I do this with a 5 gallon cooler, 5 gallon paint strainer and 8 lbs of grain. Works great. The bag is plenty big for 8+ lbs. I don't even have to tie off the bag. I pre heat cooler for 20-30 minutes with 185 degree water. Dough in as soon as I hit my strike temp (usually 16* above my mash temp). I even batch sparge in the cooler.

I've never done a BIAB method, but I don't see why it wouldn't work. Just make sure you have a tight seal on the cooler to assure you're not going to lose a lot of heat in the mash time.

Thanks. It's takes so long to heat sparge water on my electric stove, I'll be really happy to have my kettle free during mash to start heating it. Also I think the cooler will hold temps better

What size boils are you working with? I only have a 4 gallon pot. I do 3.5 gallon boils and top up to 5.5 in fermenter. You can probably mash more than 5 lbs. I'm getting 75% mash efficiency each time if your interested in my process.

I have a 5 gallon pot and I do 3.5 gallon boils. I don't think I have any reason to mash more than 5lbs for now. I ended up not brewing today because of the stupid storm. I lost power.