London - The smell of freshly brewed coffee can be hard to resist. Unfortunately, the taste doesn’t always live up to expectations.
Scientists think they know why – and it is all to do with us having two senses of smell.
When we smell coffee as it is brewing, the aroma goes up through the nose and blows across a sheet of cells that send the information to the brain. Then, when the coffee is sipped and swallowed, the scent is pushed up from the throat towards the same sheet of cells at the top of the nose. But, crucially, it wafts across them in the opposite direction.
This second, “retronasal”, sense of smell leads to the information being sent to a different part of the brain and interpreted differently, the British Science Festival in Aberdeen heard. As most of the taste of a food or drink actually comes from its smell, this, combined with many of the flavoursome chemicals in coffee being stripped out by saliva, leaves it bound to disappoint.
Professor Barry Smith, founder of the Centre for the Study of the Senses at the University of London, said: “The smell of freshly-brewed coffee is absolutely wonderful. It’s intoxicating.
“But aren’t you always just a little disappointed when you taste it?
“People waste a lot of money trying to get better machines, the right pressure, sourcing the beans but it will never happen. When you put it in your mouth it mixes with saliva and that strips off about 300 of these volatile chemicals and they are never going to reach the nose again. What does reach the nose is going to have a different character to it because the brain actually cares about the direction the air is flowing across sheet of receptors across the top of the nose.
‘”nd of course, the companies that sell you it know that. It’s wake up and smell the coffee. It’s not wake up and taste it.”
Professor Smith said the reverse is true with whiffy cheeses which taste better than expected.
“Think of a smelly cheese, it smells like a teenager’s training shoe,” he said. “You think ‘do I really want to eat that?’.
“But once it’s in your mouth and you are experiencing the odour through your nose in the other direction, it’s delicious.”
There is however, one food that always lives up to expectations. Chocolate. No matter how it is smelt, the brain decodes the signals as being delicious. - Daily Mail