That's what you detect as flavour with your brain. The chocolate helps because it has fats of its own - the cocoa solids and they enhance the effect. Hobnobs release eight times more flavour with hot milk. Jaffa Cakes release seven times more flavour with orange juice or squash. Ginger Nuts release four times more flavour with cold milk.
Caramels release three times more flavour with hot chocolate.
Dr Fisher said the big surprise was that tea and coffee faired so badly in the tests. I was expecting that the hot drinks would vaporise the aromas and you'd really get a nose full. But it doesn't work like that because hot drinks also wash the flavours straight down your throat. The worst drink to have with a biscuit is a soft drink like lemonade. Flavour goes down by a factor of ten instead of up, says the honorary research fellow at Nottingham.