Does Vanillin and Ethyl Vanillin content in fragrance oils matter?

Vanillin is used in fragrance oils when the scent of vanilla is required.
It can be a naturally occurring ingredient, as its formed on the outside of the vanilla bean, however most Vanillin is synthetically produced.

Ethyl Vanillin is a synthetic chemical that is similar in structure to Vanillin.  Ethyl Vanillin is three times stronger than Vanillin, but it is slightly different in scent.

Fragrance oils that contain Vanillin or Ethyl Vanillin will oxidize faster than fragrance oils that do not contain this ingredient.
Oxidation causes the fragrance oils to become darker in colour over time.

This is not a problem if you are using dye in your candles or soap or you want your products to be naturally darker.

If you are not using a dye and want to keep your products light this may be when Vanillin can be an issue.

The darker colour could show up immediately or it could take much longer. It just depends on the formula of the specific products you are making.  

Having your finished product appear darker in colour does not affect its scent throw, it is simply important to be aware of Vanillin for the appearance you are trying to achieve.

Fragrance oils that are higher in Vanillin content may also crystalise when the weather is colder. The Vanillin portion of the fragrance will appear as small white crystals. These crystals will redissolve when the oil warms up, you can speed this up by running the bottle under warm water.

The integrity of the fragrance is not compromised; it simply separates if the temperature gets too cold.