Dane said:
Yeah, warming plates are the number one cause of crappy coffee-with dirty coffee residue in the machine being the second. I'm not even sure why Technivorm offers that as an option. Unless, and this wouldn't surprise me, the burner has some way to regulate the temperature such that the coffee doesn't burn. It's really the old coffee gettig too hot and scorching that is the problem with other machines. I suppose if it could be held in the "warm" zone, it would be fine. I- Josh O.
The coffee getting to hot drying out and then burning is the lessor problem the bigger problem is keeping the coffee hot allows the oils, which are released with hot brewing, to react with oxygen and go rancid. If it's kept too hot then it just goes rancid faster.
All hot brewed coffees have this problem. The only ways to avoid this reaction is to exclude air from the hot coffee (canned coffee does this) or use cold brewed coffee which dosen't have the oils in it