What is the difference between vanillin and ethylvanillin?

The vanillin molecule can be found naturally whereas ethyl vanillin must be synthesised from a chemical source resulting in a sharper and more chemical taste.

Vanillin, also known as methylvanillin, is the key molecule that gives vanilla its distinct flavour. It can be derived and produced from various sources, but the molecule remains the same. On the other hand, ethylvanillin has a similar vanilla taste, but it is significantly sharper with a more chemical note and almost three times more intense.