(Photo: Dan the Chemist)
The only thing better than a chocolate bar is a chocolate bar that’s been chilled. Why? Dan, a doctoral student in chemistry, explains that the cocoa butter in chocolate exists in six different forms depending on the temperature. When chocolate is about 34-36⁰C, the structure of it begins to break down. This is called “fat bloom.” You can see it when chocolate appears to turn somewhat dusty and splotchy, such as the example above. Dan writes:
You then might ask how you can tell this has happened? The change in crystal structure is usually accompanied by something called ‘fat bloom,’ which is where the chocolate begins to look dusty, and pale spots appear on the surface as shown in the attached image. We’ve all been there (you’re incredibly lucky if you haven’t). It’s off putting, but still safe to eat. It happens because of partial melting in the solid which cases the fats within it to rise to the surface. It’s this strange occurrence that leads me to believe that keeping my chocolate in the fridge is in fact the correct way to keep it, and also why all the chocolate I bought on my exchange year in Australia just didn’t taste as good as the stuff at home in the UK due to their hotter climate!
-via TYWKIWDBI
Much more experimentation needs to be done, by everyone, on a very large sample size, over a long stretch of time. As a personal sacrifice, I will consume large amounts of different brands of chocolate, in different ways, over the next decade, in order to verify the results.
However, even when I lived in a hot climate, it took weeks for chocolate to lose its temper at a warm room temperature, and when it happened it is visually quite obvious. Whether or not your chocolate is cold at the time you eat it is not going to change the temper. But temperature can change what flavours you notice most, and you can already find endless arguments online about the temperature of things like beer and whiskey.