I arrived in Puligny, at my friend Mary’s house, the other weekend, and she handed me a flûte salée from her favourite boulangerie in Beaune. It was celestial: an apotheosis of butter, almost impossibly transformed from its everyday ingredients into something of glory and grace.

Grapes – obviously – undergo an equally remarkable transformation into wine. But grapes and wine are a bit more complicated, and lend themselves to more theories. And what theories they can be.

What if somebody said to you that the young wine needs to gain energy from its surroundings at the equinoxes and at the solstices? To which end you should bring rock into the winery from the vineyard, and to make sure that the wine takes advantage of this, you should pour some wine over the rock before adding it back. Only chalk will do this (we’re talking of sparkling wine here, or rather wine that will soon be made sparkling), although semi-precious stones might have the same effect.

My reaction, too, would be to reach for another flûte salée. Better that comforting crunchiness, tangible and grounded, than the wilder shores of unprovable theory. Do bakers tell you that the I in pain  (as in bread, not toothache) is the only letter that links earth and sky? On the whole they don’t.

Perhaps some do. Perhaps the boulangerie frequented by Hervé Jestin of Champagne Leclerc-Briant does: who knows? That is certainly what Jestin says about the I in vin and presumably in ‘wine’. And it is he who says that it is necessary to pour the young wine over chalk at the equinoxes and solstices so that the wine can get information from outside.

Jestin is sober, calm, and has been making wine in Champagne for decades, including many years at Duval-Leroy, itself a sober, sensible sort of wine. So sober and calm is he that you wonder if you’ve heard aright. But you have. And as you reach for a flûte salée you might think gratefully of the pinch of salt that it contains.

But the thing is, Jestin’s wines are wonderful. And when you ask him the fundamental question that should be asked of all theories – But how do you know? – he says simply that he can taste the difference.

Is this solstice chalk a standard part of biodynamic practice? I haven’t come across it before; perhaps you have. As with all unprovable ideas, my immediate reaction is to say, Who says? (If the answer is Rudolf Steiner, I’m afraid I tend to reach for the sel in quantity.) I am open-minded: I know that there are more things in heaven and earth than are dreamt of in most people’s philosophy. But I am also a sceptic: we live in a credulous, pseudo-scientific age when magical thinking often shouts louder than hard facts, even among people who should know better. We have to look for results.

And if the results – the wines in question – are superb, alive, vibrant, as eloquent of their origins as any wine can be, what should we think then?

Jestin is a man you have to take seriously. He works not just on intuition – he is perfectly familiar with the bio-chemistry of winemaking. And it made me wonder: is our state of knowledge of some things actually at much the same level as philosophers like Lucretius, explaining De Rerum Natura in terms of  an infinite number of atoms in an infinite void, and that simulacra, very fine replicas of an object, constantly streamed off that object; when these simulacra hit your eye (which did not exist primarily for the purpose of seeing), you could see the object. Lucretius and his fellow philosophers worked on observation and conjecture to arrive at conclusions that were factually wrong (though not always entirely wrong) but well argued. Reading them now, you can see why they might have thought that.

We also know that science cannot yet tell us everything. Jestin points out that there are over 50,000 different molecules in wine, and if you work on just 15 parameters you’re going to miss an awful lot. Maybe a scientist’s answer would be that more data, a more powerful computer, would and could tell you everything; I don’t know.

I have always had problems with biodynamism, because it requires such suspension of disbelief. But on the other hand, science has always thought it knows everything, and never has. When surgeons at Guy’s Hospital in London operated, back in the 19th century, they kept their old surgical coats for the occasion. Says Diana Cooper in The Rainbow Comes and Goes, ‘These coats lived in the theatre and were so stiff with old blood that they stood up like armour.’ The idea of antiseptic surgery, when it arrived, was seen as pretty crackpot by these experienced old hands. But then more patients started surviving…

Lovers of old vines have long believed in the superiority of their wine – for ageing, for complexity. But there was no proof; only observation. Now the Campo de Borja Denominación de Origen, working with the University of Zaragoza, has found proof, and revealed its findings at the Old Vine Conference in California in early November. For its studies, it chose historic vineyards across the region and young vineyards next to them; it took Garnacha mistelas, juice fortified with spirit to preserve the primary aromas, and over four years studied 40 flavour precursors in the mistelas – precursors that can’t be detected by smell. As wine ages, these precursors slowly break down and produce the aromas of maturity. Says José Ignacio Gracia López of the DO, ‘the study forced these aromas to be expressed faster than the five years it can take for some molecules to be fully expressed.’

The grapes from the old vineyards, compared to those from young vineyards, contained more aromas derived from shikimic acid – aromas like guaiacol and eugenol – which give black-fruit aromas rather than red-fruit ones. Certain villages had more varietal thiols, vanillin and β-damascenone and were fresh and fruity; other villages had more terpenes and β-ionone and thus were more floral. Grapes from the younger vineyards, on the other hand, were all pretty much alike, no matter which villages they came from. The difference between villages – the terroir, in fact – only appeared with vine age.

Now, you could argue that proving that old vines express terroir better than young ones is not exactly earth-shattering; it’s what we all suspected. But what if the study had shown the opposite? That would have indicated that terroir is a myth; no more than a fancy of over-active vinous imaginations. It would have suggested that a love of old vines was no more than sentiment, and an aesthetic fondness for gnarliness.

But observation turned out, in that instance, to be bang on the money. Which doesn’t mean that all other observations are right, or even if they are right, that they’re right for the reasons given. Where there’s no proof we can choose how seriously to take assertions.

Absence of proof is not proof of absence. Just because Jestin’s belief in the power of chalk to connect the wine with something else sounds like the outside edge of wackiness and cannot be proved doesn’t mean we should dismiss it instantly, given the quality of the wine he makes. Doesn’t mean we should, doesn’t mean we shouldn’t. That he says he can tell the difference in the glass might encourage us to keep an open mind. I hope to meet him at Hambledon in December to see for myself.

Ideally, the Garnacha study should be replicated for every grape variety in every region, which is just not possible. Not all wines age well; some will never transform enough to justify the investment of time, the investment of anticipation.

At the Old Vine Conference, since it was in California and a lot of the oldest vines there are Zinfandel-based field blends, I tasted a lot of Zin. Some were delicious after ten or 15 years, many were delicious young. Some proved that old vines are not enough on their own to give complexity and depth. But the berries, pulled straight off the vine – second-crop berries, ripe, sweet and juicy – were lovely. Was that sometimes the perfect moment? Was it, just occasionally, downhill from there? Was all that transformation, just occasionally, a mistake?

Heresy, I know. Forget I said anything; it was only a thought.

Photo by Nadya Spetnitskaya on Unsplash