There was a precise moment when I knew the experiment was working. It did not arrive as a number, or as a line in the notebook. It arrived as a sound: my partner, at around two in the morning, gathering her pillow and moving in silence to the spare room.
But let me go back.
In thirty-five years of this trade I have tasted, professionally and with due detachment, almost everything a person can put in their mouth without ending up in a police report. Wines worth a month's salary, cheeses that should travel with an escort, olive oils that deserve their own airspace. And yet I had never done to garlic the one thing a serious taster owes any ingredient: measure it. Not the flavour — we describe that far too well already. The persistence. The tail. How long, that is, a human being remains — let us say — inhabited.
So one evening I took two heads of garlic. Whole heads, not cloves. I cut a clean centimetre off the top, seasoned them, and roasted them slowly until the cloves had turned soft and golden as a preserve.
Here I must confess the first heresy. It was good. It was, in fact, superb. In thirty-five years of tasting, that roasted head reached heights on my personal scale that I reserve for very few things: a deep sweetness, no aggression, a roundness that was almost animal. I stopped to consider that the most feared ingredient in European folklore, the one against which braids are hung on doors, can conceal — if you treat it with respect and the right oven — a delicacy fit for dessert.
Then the scientific part began. Which is also the part where I lost every remaining shred of dignity.
Why I was not the instrument
My first instinct was to measure myself. I abandoned it within the hour, and the reason is the single most useful thing I learned that week.
After roughly sixty minutes I could no longer smell it. Not because it was gone — it was emphatically not gone — but because my own nose had adapted to my own air. Olfactory adaptation is fast and it is total, and it makes the subject of a persistence experiment the worst possible judge of it.
So the readings were not mine. My partner took every one of them, from hour zero to the end, on a scale from 0 to 10, at intervals, out loud, with the weary patience of someone who did not choose this life. This is not a footnote to the method. It is the method, and every protocol we have written since requires a third-party assessor for exactly this reason.
The numbers
Hour zero, immediately after the meal: 10. Absolute maximum. Thirty-seven hours later: 7. At forty hours: 6. At forty-two hours: 5 — exactly half.
Physics has a word for this: half-life. It is the time a radioactive substance takes to halve its activity. My olfactory half-life that week was forty-two hours. Full extinction came at sixty. For the better part of two and a half days I was, to all practical purposes, faintly radioactive — a small organic reactor irradiating the room, the lift, and in all probability the neighbours across the landing.
The most interesting thing, though, is the shape of the curve. For nearly two days the intensity barely fell: a stubborn plateau, and then, abruptly, the collapse. This is not the gentle decay one would expect.
The explanation is unkind to anyone doing the measuring. The dose was so large that the reading sat pinned at the top of the scale. The molecule had been retreating for hours, but the scale could not show it — like watching a fire from too close and swearing it is not going out. The half-life I recorded is a perceptual half-life. It overstates the chemistry. Knowing that, and saying it, is the difference between a measurement and an anecdote.
The culprit
The compound has a bureaucratic, almost tender name: allyl methyl sulfide. It forms when garlic is wounded, enters the bloodstream, and — here is the real curse — does not leave through the mouth. It leaves through the lungs. You breathe it out.
Which is why brushing your teeth, in these circumstances, is an act of pure theological hope. You are not fighting an odour in your mouth; you are exhaling a molecule that rises from somewhere much deeper. Toothbrush against vampire: the vampire wins.
There is a second tail, more intimate, that modesty prevents me from plotting. Two whole heads are also a respectable dose of fructans, and a certain sense of fullness — solemn, persistent, almost monastic — kept me company well beyond what was reasonable. I noted it scrupulously and carried on. A taster does not complain. A taster documents.
What it started
Legend has it that vampires flee from garlic. I spent forty-two hours proving the opposite with some pedantry: that one can stay, smell, time, take notes.
My partner, from the next room, delivered a second kind of data that night — non-verbal, unrequested, and entirely unambiguous. Two channels, one subject. I have been designing experiments around that principle ever since.
I will not yet tell you why I was really measuring all this. Let us say that a food journalist who times his own breath for two and a half days is not doing it out of boredom. Let us say there is a method behind the madness — sheets, scales, doses weighed to a tenth of a gram — and that very soon I will no longer be the only one looking garlic straight in the eye.
They flee. We, meanwhile, taste.