To his surprise he found that the best dunking liquid is not hot tea or coffee - but a milk drink. To analyse the smells, his team inserted a tube into one nostril of the eager volunteers. The different flavour chemicals from each sample of air were separated and then analysed. And sure enough, dunking your biscuit into a milky drink gives you up to 11 times more flavour release than from eating the dry biscuit alone. Well, the answer lies in the fat in milk.
Milk is basically little tiny droplets of fat which are suspended in water.
These droplets of fat do two things. First, they absorb the flavour molecules really well. Second, these little fat droplets also hang around in your mouth, so that the flavour and aroma chemicals can sit on your tongue AND be released up to your nose. But hot non-milky drinks tend to carry the flavour molecules straight down your gob and into your gut before the taste sensors on your tongue and the olfactory epithelium in your nose have had a chance to fully appreciate them. His team also found that the worst drink to have with your biscuit is a soft drink such as lemonade.