Recipe(tried): Holding mashed potatoes...

Mashed potatoes do develop an off flavor when chilled and then reheated. I read in a Julia Child cookbook a hint that has worked for me if I wanted to hold them for less than an hour. She said that leaving the lid ajar so air can circulate seems to keep them from developing an off taste and I have found that to be true. I mash the potates and leave them on a warm setting with a spoon in the pot and the lid propped on the spoon. If holding more than 15-20 minutes, stir occasionally. If they become stiffer than I like, I add hot milk before serving.

Also, I have noticed the reheated taste doesn't seem to happen when they are reheated in the microwave.