The Scientific Bit

Like snow flakes, sugar is a crystal. When it melts the water contained in its molecules renders it liquid. This is why heated sugar dissolves into a syrup. As it boils the water evaporates and the sugar begins to cook and color. Heat breaks up the molecules and transforms the simple taste into a complex mixture of millions of different flavors— all for our pleasure.

This is caramel. The darker it is, the stronger the flavor. But take care—it takes only a few seconds to turn a rich dark caramel into bitter burned sugar.