We have not heard of coffee turning toxic but it does start to lose flavor as soon as it is brewed. You should be able to keep it in an airtight container in the fridge for a couple of days. The longer you keep it, it tends to pick up odors and flavors of other food stored in the fridge.

Thanks for this great tip ! I have a question about coffee in general. I have heard that storing freshly brewed coffee in the refrigerator for few days is toxic to health. I usually like to chill my coffee in the fridge so that I can enjoy iced coffee later on. Is it really toxic to store brewed coffee in the refrigerator ? thank you.

Sure…just cool down the coffee and then add it to a blender with hot cocoa mix and ice. Blend until smooth.