That sort of market research, though, is both time-consuming and expensive. It would speed things up, and probably cut costs, if it could be mechanised. To a certain extent, can be. Cheddar cheese, coffee and tea researchers are all exploring the use of electronic noses to rate their foodstuffs. Simple versions of such devices employ a set sensors made of special polymers linked to electrodes. The volatile compounds that make up aroma cause these polymers to change shape, which alters the resistance to the current passing through the electrodes. The result is an electrical fingerprint' of an aroma.