Hey, If you haven't guessed from the title this is kind of a weird question. I'm a science student at UBC and for a lab today we had to analyze vitamin C contents in a substance of our choice. Long story short, I decided to look at how temperature effects Vitamin C concentration in tomato juice. Anyway, I'm posting this because something weird happened when the juice got up to 85 degrees Celsius, it started to cool down despite the fact that heat was still being added to the system. It was in a glass beaker with a tinfoil top (to prevent evaporation) and a small hole just big enough to fit a thermometer through. The tomato juice continued to cool down to ~80 degrees Celsius before heating up again. Can anybody explain why this might happen? My thoughts are that at around 85 degrees molecules begin to decompose and that makes the heat constant shoot up dramatically but I have no idea.