The same plate of coriander can smell fresh to one person and like soap to another. The difference begins largely with smell. Much of what we casually call taste comes from volatile compounds reaching the nose, and coriander leaves contain several aldehydes. Some of these can also evoke soap or cleaning products.
A large association study published in 2012 found that a genetic variant near a cluster of olfactory-receptor genes was associated with detecting a soapy quality in coriander. The region includes OR6A2, a receptor that responds to several aldehydes found in the herb. This supports a genetic contribution to smell perception, but it should not be simplified into “one coriander gene determines whether you like it”. Common variants explained only a small proportion of the difference in that study, and the authors presented OR6A2 as a plausible contributor rather than a proven sole cause.
Two people can therefore encounter the same plant while receiving different strengths of signal from the same molecules. Exposure, preparation, memory and food culture also influence whether the final experience is pleasant. Chopping, heating or combining coriander with other ingredients can alter the mixture of aromas reaching the nose. The central point is that the soapy sensation is a real perceptual difference, but it emerges from molecules, receptors and experience together, not from a single gene alone.
https://flavourjournal.biomedcentral.com/articles/10.1186/2044-7248-1-22
https://www.nature.com/articles/nature.2012.11398