Cooler Mashtun Stain Question

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Aug 23, 2007
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I can borrow an Igloo cooler from a relative to use as a mashtun, but only if it doesn't stain the interior white walls of the cooler. I've seen pictures of coolers in use for this purpose on this site and elsewhere, but I thought I'd ask just to be sure.

Do these coolers end up stained from the steeped grain?
MLT coolers will almost always stain to some degree. If you scrub like hell with a LOT of bleach many times it will come back to bright white, but go buy a 20.00 cooler and don't worry about it.
and if the cooler was ever filled with something like kool-aid, it might impart some flavors into the wort.

plus I'm assuming this is a larger cooler that you're gonna put a ball valve on with a SS braid or a false bottom for sparging after the your relative ok with you disassembling the cooler?

I'd honestly just buy one. even a 5gal is $18-$20 and will make 5 gallon batches that push 1.060 OG (12-13 lbs of grain before it gets tricky).
I agree with buying your own cooler. The other thing to be aware of is the plastic deforming from the hot liquid. Mine is over 10 years old and it has recently started deforming. I don't know if the one you want to borrow will do that. Just something to be aware of.
The people teaching me how to brew AG told me a cooler would eventually fall apart, but these guys are doing 11 gallon boils at least four times a month. I was hoping to use the cooler for a test batch because I wanted to get started as soon as possible and hadn’t considered the issue of staining. I plan on getting/making a steel or aluminum mash tun—I just don’t have it yet.

BTW Walmart has a round five gallon cooler with a spigot for $17. No major mods necessary—just unscrew the spigot and replace it with a one-hole stopper, some copper tubing and stainless steel braid.

Thanks for your comments.
Also unless you are dedicated to Fly Sparging, there is no reason to limit yourself to a round cooler. Go buy a 48 quart square one for the same price and you will not have growing pains in a year when you want to make a huge batch.