We have an insulated wort holding tank that holds our wort until the mash-kettle is done mashing and ready to boil. I want to put a heating element in this tank to bring the temp up to around 180+. In order to avoid scorching, I'll need to use a low watt density element.

What range is considered low?

I am also planning on placing a low rpm agitator above the element or installing a low flow circulation across it with a pump.

Any other heating ideas are welcome.