Continuing the foodie theme to my science factlets this week, today’s is about the aroma of aniseed.
The chemical that produces the characteristic aroma of aniseed (which comes from a plant related to the carrot) is a phenolic compound called trans anethole. It’s also found in fennel and star anise.
Weight-for-weight, trans anethole is 13 time sweeter than table sugar, which may explain why star anise and fennel seed are chewed in China and India respectively as a breath freshener.
It is found in high concentration in anise-flavoured liqueurs like Ouzo and Arak, and causes them to turn milky when water is added to dilute them, as it is more soluble in alcohol than water; when it is diluted, the anethole comes out of solution and clumps together, disrupting the light.