Description and usage notes:
Very intense, good tenacity, a classic aliphatic aldehyde with nuances of ambergris and incense among other notes. When smelt in concentration it is sweaty and metalic but in dilution floral and herbaceous qualities are revealed. Very different from other aldehydes except in power, it can also be used to enhance the effect of musks in a fragrance.
Arctander writes enthusiastically about it, including: “This aldehyde is probably one of the most preferred perfumery aldehydes with respect to ‘aldehydic topnote’. It blends very well with Galbanum, the Hexenyl family or the Methyl phenyl carbinyl esters, the Methyl-ionones or with Oakmoss. … It lends excellent notes to a ‘Tabac’ base and blends well with Vetiver for such purpose. In Mimosa it will supply part of the peculiar dry notes, and in Ambre fragrances it is an almost inevitable component. Interesting effects are achieved with Ginger oil and Clary Sage.”
This is one of those superpower ingredients that is used in traces. If you normally work with ingredients diluted to 10%, we recommend using this at 1% or even 0.1% – it’s very easy to overdose.
Bedoukian writes that “methyl nonyl acetaldaldehyde … is considerably more stable [in alkaline media than the other aliphatic aldehydes]” He also notes that it “possesses an odour which is surprisingly different from the other aldehydes. It has perhaps the most ‘animal’ note of them all. Its somewhat sweaty odor on high dilution imparts a distinctive quality to perfume compositions”