Cassis mercaptan

Say itkah-SEES mur-KAP-tun

Blackcurrant bud and box-tree leaf; catty and sweaty when strong.

What it is: A molecule made in a lab.
Where it comes from: occurs in blackcurrant, box tree and Sauvignon Blanc
When you smell it: Top notes: the first minutes.
What perfumers do with it: Adds cassis and tropical tang at parts-per-million; the sulfur secret of many fruity accords.
Worth knowing: The same molecule makes Sauvignon Blanc smell of blackcurrant and, at higher levels, of cat pee.
Also called: 4-Mercapto-4-methylpentan-2-one; 4-MMP; cat ketone

Not on the label of any of the 232 perfumes read so far.