Every now and again I get a flashback of some smell. I can’t explain it; I don’t know what triggers it, but it’s every bit as vivid as my visual memories. I get it with taste as well. It can be incredibly frustrating at times because I often can’t identify the smell or taste despite it being such a strong sensation, as if I were smelling or tasting whatever it is right at that moment.

In that respect it is different from my normal memories of smells or tastes – they are nothing like as involving. Normally, to recall the taste of something I have to imagine eating or drinking it, and the memory is but a dull echo of the reality. But with the involuntary sensation of a smell it really is as if I am experiencing it right there and then. I can draw a deep breath through my nose and it sets off my olfactory nerves like fireworks. Even though I’m not actually smelling anything – there’s no odour in the air.

The strange thing is that my senses of smell/taste are not very acute. I often have trouble differentiating smells, so most perfumes smell about the same to me and I can’t distinguish between wines, say, by the aroma. I even find it difficult to tell if milk has turned by sniffing it – the first indication is usually when my wife tastes it in her cup of tea. I once – years ago – made cups of coffee at work and only realised something was wrong with the milk when I spotted the curdled bits floating. So it’s a mystery to me why I should experience these illusory flashes on what are very much secondary senses to me.

I refer to them as flashbacks rather than hallucinations because they are familiar as sensations that I have experienced first-hand in the past, not inventions of my mind. It happened earlier today – the inspiration for this post – when out of the blue I smelled Apple Sourz. I know that I smelled it yesterday when I was cleaning an optic that had been used to dispense that drink at the pub. I only wish I knew why the memory of that smell suddenly surfaced so vividly.