Instruct: Classify Amazon reviews into positive or negative sentiment
Query: keeps coffee hot! Makes coffee taste like plastic :(

I rate the thermal properties excellent. It keeps coffee hot all day. 24 hours later coffee was still warm. However, I bought this Thermos so I could bring great tasting coffee from home to avoid the less than desirable coffee at work. Unfortunately the thermos itself imparts a "chemically" test to the coffee. Just to be clear I don't mean after 24 hours, I mean the first cup tastes bad. I've repeatedly washed and rinsed the container. The taste is becoming less prominent but it's still there. Not sure why I'm the only one that has noticed this...Maybe mine is defective??