I fear I have not given enough thought to my nose. The role it plays in the appreciation of food figured prominently in a book I was reading recently, and I thought the time has come for an ode to the nose.
“The most impressive, yet underrated, arsenal in our flavor-detection apparatus are the olfactory receptors in our noses,” writes Krish Ashok in Masala Lab: The Science of Indian Cooking.
I had never really associated coriander leaves with the nose, but I do so now. The herb has been on my mind for a while. It caught my attention when there was a shortage of fresh coriander in the market. That got me thinking. Do we really need to put coriander leaves in our food, I asked anybody who would listen. Just what do we need the coriander for?
That’s where the nose comes in. “Its name comes from koris, the Greek word for bedbugs, because the ancient Greeks thought that the seeds smelt like the insect,” writes Ashok. That’s not all. While most people find it citrusy or woody, some associate the smell with soap, he writes.
“A sizeable section of the population has a visceral aversion to coriander (4-14 per cent depending on their ancestry) in its leaf form. It turns out that it is not an irrational personal choice but genetics. Coriander’s flavour molecules are a family of compounds called aldehydes, and the ones present in the coriander are also found in soap,” Ashok tells us.
What’s interesting, he adds, is that when you crush or grind coriander leaves, an enzymatic reaction breaks down these soapy aldehydes — “which is why people who can’t tolerate the leaves as a garnish don’t mind coriander chutney in their chaat.”
In a chapter called ‘Science of Spice and Flavour’, the author describes the role of spices and herbs, and how tastes and aromas can be enhanced (with the help of temperature, for instance). I found it particularly interesting, because it solved some age-old riddles. I had often wondered how my East Bengali mother could be fond of a preparation of shutki maachh or dried fish. It stank to high heaven when the fish was cooked, forcing everybody (barring my mother) to frantically rush out of the house.
But there is a reason why some dishes may, well, smell fishy, but are delicious when eaten. Ashok explains that there are two types of olfaction or the sense of smell. Orthonasal olfaction is what you smell before you eat something. Then there is retronasal olfaction: “What you smell as a result of a ton of volatile flavour molecules hitting those receptors as you breathe out.”
Take the case of strong cheeses. You may recall what happened when Jerome K. Jerome carried some ripe and mellow cheeses for a friend in Three Men in a Boat. First, the horse pulling the carriage in which the writer was travelling with the cheeses went berserk. Then, in his train compartment, a gentleman went out without a word. A stout lady said it was disgraceful that a respectable married woman should be harried in this way, and left. A solemn-looking man, who looked like an undertaker, said it put him in mind of dead baby. “And the other three passengers tried to get out of the door at the same time, and hurt themselves.”
But let’s not sneer at cheese (or shutki), for more than taste, the reaction to aroma is highly culture-specific, Ashok reminds us. For instance, he says, roasted cumin powder smells like sweaty feet to people not used to the spice.
“Malodorous feet and cumin aside, smell is the only sense that goes straight to the brain’s cortex — the olfactory nerve is close to the part of the brain that deals with emotions and memory, which is why the smell of food evokes nostalgia and memories, and also why no Michelin star chef can compete with your grandmother’s dal.”
I tip my hat to my nose. It doesn’t find cumin malodorous. And, thankfully, doesn’t associate coriander leaves with soap or bedbugs. Well done, nose!
Rahul Verma likes reading and writing about food as much as he does cooking and eating it. Well, almost.