It’s too late in the season for all this water to have much good influence on the flavours of 2017.

If anything, growers will face big trouble when the spring properly arrives and the weather warms and settles: there’ll be a huge surge of leaf growth which will cramp canopies and make it hard for any breezes to penetrate that thick green thatch.

Unless there’s a lot of fungicide spraying, like too much, vignerons will have to be shoot-thinning and leaf-plucking to admit the drying and healing breezes to the bunches as they form and swell.

Bayer, the new owner of agrochem company Monsanto, has been hard at work teasing the paranoia and pride of grape farmers, pumping the conscience of the lot of them with full-bore social media advertising of its fungicide, Teldor. Drinkers who read the back-label instructions may well hope any growers who use this stuff would advise us of its use on the back labels of the wine, just so’s we know. The incessant ads are there right now. Bayer’s also going for the strawberry growers.

Botrytis and other moulds aside, these dramatic rains will do one other thing to many vineyards. In some, the fruit will likely be minty with eucalyptol.

In the late ’70s and early ’80s, a lot of reds from the new cooler-climate regions like Heathcote, Bendigo and the Yarra Valley were sometimes very minty. This excited show judges looking for new aromas and flavours. These wines often came from vineyards in forested regions.

Many boring tasting games depended on the drinker identifying these prospective vignobles by their pepper – which usually indicated unripe fruit – or what we called mint or peppermint, which we eventually learned was really eucalyptus.

When the terrible fires had been extinguished on Ash Wednesday, in 1983, there was a teasing belting of rain that came too late to help. Instead, it washed a lot of precious scorched topsoil away from the areas that were burnt. In those that weren’t, the water deposited a thick layer of gum leaves it had brought from upstream as it flooded through vineyards.

When those ’83s were eventually poured, with tasting games like Options one could tease the proponents of those trendy new cool spots of Victoria. If one poured, just for example, a Shiraz from the slopes of Stockwell, Light Pass or Nuriootpa, it was so stacked with eucalyptol the taster would often imagine it must have come from those forested regions to our south-east. In the memories of most, the rich, ripe Shiraz of that north-east Barossa had not previously showed that character so overtly.

Some winemakers were very pleased about their usually blackberry-and-chocolate reds suddenly showing some of the style of the exciting new regions across the border; others regarded it as an alien intrusion and attempted, usually in vain, to dilute and diminish its character by blending or masking it with toasty American oak.

But it was fun to trick pompous old wine buffoons who thought they knew everything with glasses of, say, Elderton Shiraz from Nuriootpa: they tended to sniff that minty eucalypt and say “Bendigo” or “Heathcote”.

The first person I met who knew the source of this new aromatic was John “The Ferret” Glaetzer, the master nose and vineyard expert behind the success of Wolf Blass.

We’d been having a beer in Paulos’ pub in Tanunda sometime after the Ash Wednesday reds had begun to appear, when I suggested the source of the “mint” or “peppermint” was in fact eucalyptus.

“Whatterya doing this arvo?” Glaetzer queried, through a cloud of tobacco. He offered me a seat in his car: he was off to Langhorne Creek to collect ripening bunches for analysis back in his Barossa lab. His was the only company car in the Blass camp with a sunroof: folks in the know joked about him needing it to let out the smoke. I recall a cartoon somebody drew of that Falcon, tearing across the countryside like a steam locomotive.

We laughed and smoked all the way down the Bremer Valley through Harrogate, Kanmantoo and Callington to Larncrk, as he called called it, me mystified by the nature of my inclusion in the exercise.

When we got there, we went from vineyard to vineyard. My job was to collect soil samples from beneath the vines he sampled, and take notes of the appearance and aspect of each site, paying particular attention to the number of adjacent red gums.

Back in the lab, he crushed each bunch and put its juice in a numbered glass. The relevant soil samples were lined up in little piles, also numbered, on another clean white bench and an assistant shuffled both lots of samples. We sniffed the glasses for an hour. Most showed, some overtly, the aroma we’d called mint.

Then we sniffed the soils. Those with the most obvious mint, or eucalyptus, generally matched the bunches with the same bouquet, and tended to come from the vineyard my notes showed to have the most red gums surrounding them, or indeed, big ones growing among their vines.

From this highly unscientific exercise, we agreed that the eucalyptus in the soil, or in the air, was volatile, so its airborne particles must have settled on the matte blume of the grape skins, where it stayed until skin contact with the fermenting must transferred the aroma into the wine itself. You needed only a few parts per million or trillion or something minuscule to obtain the effect.

“That’s where our Jimmy Watsons come from,” the Ferret enthused: he’d just won his boss three Watson trophies in a row; still the record. “The show judges can smell it through the fruit and the oak, whether they recognise it or not. They seem to like it.”

A few years after those Ash Wednesday floods, the eucalypt in the Stockwell/Light Pass/Nuriootpa reds had declined to previous levels, but the young Whitey’s hooter never forgot that eucalyptus was something to look for in the snifters.

Of all South Australian vineyards, it was Glaetzer’s Langhorne Creek favourites that tended to exude the aroma regardless of whether or not their source had been flooded during vintage. The stuff was in the ground.

I wouldn’t dare suggest that 2017 will smell of gum trees across the board. But I’m willing to bet that if and when this water ever goes down, growers whose vineyards sport a new layer of eucalypt leaves may well find a new mintiness in their reds.

When the 2017 berries grow fat and full, that eucalypt will rise from the ground and settle on their skins, especially when the humidity soars in a summer thunderstorm.

If they’re lucky, this might see them coming home from the Melbourne Show with a Jimmy in the boot.

On the other hand, growers of whites will want none of it. You don’t want eucalyptus in your Riesling, Savvy-b or Chardonnay. Please Bacchus, Pan, Huey … anybody listening …

One other thing. While these persistent deluges will pump leaf growth and then the 2017 bunches to a discomforting degree, they’ll be having a profound influence on the tiny buds already forming deep inside the vine wood for the 2018 vintage.

As the remarkable weather diaries at Kay Brothers’ Amery show, it’s almost invariably the year after sousing rains that are the greatest producers of flavour.

Any grower who can’t manage and control 2017 by finicky shoot-thinning and then leaf-plucking, maybe even bunch-thinning later in the piece, could console themselves in the hope that my theory delivers the bacon, if not the Big Jim with their 2018 wine.

Touch wood. But make it seasoned French oak, not red gum.

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