use for my mash tun;  when pre-heated with boiling water it will hold my mash within 2-3F easily for 60 minutes and more.  replaced the spigot w ith a 3 part ball value and some silicon washers.  no leaks.  have used to make several 6 gallon batches of beer.  I think you could probably do up to a mash 25lbs of grain which would take you to a 10-11 gallon batch of beer,  but I haven't tried that much . . . . yet.