By Harold McGee
The pungency of ginger and members of its family comes from the gingerols, chemical relatives of the chilli’s capsaicin and black pepper’s piperine. The gingerols are the least powerful of the group, and the most easily altered by drying and cooking. When ginger is dried, its gingerol molecules lose a small side group of atoms and are transformed into shogaols, which are about twice as pungent: so dried ginger is stronger than fresh. Cooking reduces ginger pungency by transforming some gingerols and shogaols into zingerone, which is only slightly pungent and has a sweet-spicy aroma.