

Taste buds. Photograph: Getty

I'd always assumed I couldn't become a chef because I have no sense of smell, a condition called anosmia, which influences how I perceive flavour. That was until I heard of Grant Achatz, the chef at critically-acclaimed restaurant Alinea in Chicago, who features in July's Observer Food Monthly. He has temporarily lost the ability to taste after treatment for tongue cancer, yet still produces delicious dishes.

I have no recollection of possessing a sense of smell, yet it was only when I was nine that I realised I had anosmia. Until then, I would chime in with "smells great" when my siblings complimented the aroma of our mum's cooking. As a teenager I began to complain that her dishes were rather bland, but it turns out it was nothing to do with her cooking skills and everything to do with my anosmia.

Anosmia for me also means I can't eat anything spicy - I can taste the fire, but am unable to savour the flavour. It's the sight and sound of a table being laid, not the smell of sizzling bacon, that makes me hungry.

When I was younger my parents worried about how much I was drinking - malt vinegar, that is. As an adult I've taken to drizzling it on to my food rather than swigging it from the bottle.

I've been known to serve my family what I thought were cups of English breakfast tea with milk, only for someone to realise that I'd actually taken the bags from the peppermint tea jar. Now I enjoy drinking peppermint tea with milk - which a friend with a sense of smell says tastes like cough medicine.

So what is going on when you taste something? A mouth has a million taste receptor cells, which generate and mediate messages to the brain. Each receptor's taste hair responds best to one of the basic tastes - sour, sweet, bitter, salty and umami (salts of certain acids). This is what science calls taste (although there is debate over whether there are five or seven basic tastes). What we would more commonly refer to as taste is really flavour perception - the summation of taste, aroma, texture and visual presentation.

This footage of a blindfolded anosmic struggling to recognise flavours demonstrates how a person with the condition tastes food without smell. According to Dr Alan Hirsch of the Taste Treatment and Research Foundation in Chicago, 90% of what is perceived as taste is actually smell. Some experts believe that roughly four in five taste disorders are really smell disorders, so when people tell me I don't have a sense of taste they aren't too far from the truth. Anosmia influences my ability to perceive flavour.

Millions of people around the world have a smell or taste "disorder" - amongst them are the actor Bill Pullman and the Guardian's Lucy Mangan. Ben Cohen, a founder of and taster for Ben & Jerry's ice cream, has anosmia, and this is apparently why the firm's products are so rich with other sensory features - chunks, colours and textures.

As well as anosmia, there are other smell disorders that influence the ability to perceive flavours, along with a host of taste disorders. Upper respiratory infections, head traumas or idiopathic causes are usually behind taste dysfunctions.

Losing your sense of taste can be very traumatic: what once tasted delightful can suddenly be as appetising as chewing on cardboard. In the words of Grant Achatz: "You make yourself a vanilla milkshake. Grab some Häagen-Dazs vanilla, add whole milk. You think you know what it's going to taste like, and it tastes like nothing. All you get is thick texture." One person with anosmia I met had such vivid memories of how strawberries tasted when she could smell that she cannot bear to eat them now.

Eating disorders also influence flavour perception, and scientists have found that former anorexics taste food differently. What you eat can temporarily tweak your sense of taste, too. Famously, the "miracle berry" renders bitter and sour foods, such as a lemon, sweet for up to two hours.

Even slight differences in the genetic make-up behind receptors can cause one person to feel the need to pile sugar in their tea while another doesn't. These differences can make cooking a family meal a nightmare - what one member loves to eat, another may loathe.

Even if you manage to find a way to cater to all your family's food preferences, you still won't have conquered individual taste differences, because as we age our taste buds degenerate. So that favourite dessert that your dad loves may no longer go down so well when he next comes to visit.

So how can we meaningfully discuss taste together? Despite my issues with perceiving flavours, I do enjoy eating and discussing food. And if individual tastes vary so dramatically, can we really trust what food critics have to say? Maybe reviewers should all be put through taste tests, with a note attached to their articles stating what scientists have found out about their perception of flavour. Or perhaps we should accept that an opinion is just that, and get on with eating what we enjoy.