The first properly cold evening of the year has a sound to it: the heating ticking on, a door shut against the dark, and the particular glug of something brown being poured into a glass. Reach for the right bottle on a night like that and the whole room changes. Sherried whisky is the dram built for exactly this weather, all dried figs and orange peel and the top note of a Christmas cake somebody made in good time. It is autumn, poured. And it is quietly having its moment.

Walk into any decent bar this side of October and you will notice sherry creeping back onto the menu: a chilled fino with the olives, a copita of oloroso where a glass of red used to go. That revival has a knock-on effect most people miss. The same sherry casks that make the wine so good are the ones that give whisky its richest, most autumnal character, and they have never been more sought after.

What 'sherried' actually means

Whisky takes almost all of its colour and a great deal of its flavour from the wood it sleeps in, and most Scotch spends those years in old bourbon barrels, which lean towards vanilla, honey and coconut. Sherried whisky is the other tradition. Here the spirit is matured, or finished, in casks that once held sherry: big European oak butts seasoned in the bodegas of Jerez before they ever meet a drop of Scotch. The wood arrives already soaked in dried fruit and spice, and it hands all of that straight to the whisky.

This is the style that made Macallan's name. The distillery built its reputation on sherry maturation, and even its everyday Macallan 15 Year Old Double Cask runs the spirit through both American and European oak before marrying the two, which is sherry's fingerprint softened for a wider room. Once you have tasted a properly sherried whisky the vocabulary makes sense on its own: this is the one that smells of the Christmas cupboard.

Oloroso, amontillado, PX: the cask makes the dram

Not all sherry is the same, and neither is sherried whisky. The style of sherry the cask once held tells you most of what the finished whisky will taste like. Oloroso is the workhorse and the classic: rich, dry, nutty, all walnut and dried fig and polished leather. It is what people mean when they talk about a sherry bomb, and it is the backbone of bottles like the Tomatin 18 Year Old Oloroso Sherry Cask Finish, a Highland malt that wears its oloroso finish like a velvet jacket.

Amontillado is the drier, saltier cousin, nuttier and more savoury, and it turns up far less often in whisky, which is exactly why the Glen Moray Warehouse 1 Amontillado Cask Finish is worth seeking out: it swaps the usual sweetness for something closer to roasted almonds and sea air. Then there is Pedro Ximenez, or PX, the darkest and sweetest sherry of all, pressed from sun-dried grapes into something close to liquid raisin. A PX cask pushes a whisky towards treacle, date and espresso, and a little goes a long way.

Why autumn belongs to sherried whisky

There is a reason the sherried style feels wrong in July and perfect in October. Those dried-fruit and baking-spice flavours are the exact register of the season: stewed apples, bonfire smoke, the first mince pie eaten too early. A light, grassy whisky is a summer-evening drink. A sherried one is a jumper-weather drink, the liquid equivalent of pulling a chair closer to the fire.

It also lands at the right moment commercially. Sherry the wine is enjoying a genuine renaissance, led by sommeliers who never stopped loving it and a new crowd discovering that a chilled fino does more for a plate of jamon than almost anything. As the wine climbs back into fashion, the whisky that borrows its casks rides the same wave. The flavours you are learning to love in a glass of oloroso are already waiting in the dram.

The reason it is getting rarer

Here is the quiet tension behind every sherried bottle. The world drinks far less sherry than it did fifty years ago, which means far fewer genuine sherry casks come free each year, just as whisky has never been more popular. Good sherry butts have become one of the most prized, and priciest, things a distillery can buy, and many now commission their own oak and have it seasoned in Jerez to order. None of which you need to think about while drinking. But it does explain why a deeply sherried whisky carries the price it does, and why the style feels a little like a luxury worth catching while the casks last.

Where to start

You do not need to spend a fortune to understand the style. The Glendalough Double Barrel, an Irish single grain finished for six months in oloroso casks, is a gentle, affordable way in, all soft toffee and orchard fruit. A step up, the Dalmore 15 Year Old spreads its sherry influence across three different cask types and comes out glossy with chocolate orange, the kind of whisky that converts people who were sure they did not like whisky.

From there the island malts are worth a detour. Highland Park 18 Year Old, long whispered about as one of the best-value older sherried whiskies in Scotland, folds a thread of heather smoke through all that dried fruit, while the Tobermory 17 Year Old Oloroso Cask Matured from the Isle of Mull shows what full oloroso maturation does to a coastal spirit: rich, salted and quietly unusual.

Those two bottles bracket the whole style between them. The Tomatin 18 is the generous, value-driven oloroso dram you can pour on any cold Tuesday, while the Glenfarclas 25 Year Old is what happens when a family distillery leaves its spirit in sherry wood for a quarter of a century: so deeply integrated that it has, in its own words, stopped being about sherry at all and simply become itself.

How to pour it

Sherried whisky rewards a little care and punishes none. Use a glass that narrows at the top, a copita or a tulip, the same shape sherry itself is served in, so the aromas gather rather than scatter. Pour it neat first, then add a few drops of water: with these richer whiskies that splash opens the dried fruit and tames the alcohol, and you will smell the difference before you taste it. Skip the ice, which shuts the flavours down just when you want them talking.

And give it something to eat. Dark chocolate is the obvious partner and a very good one, the bitterness meeting the whisky's sweetness halfway. A wedge of hard, salty cheese does more than you would expect, as our guide to whisky and cheese happily explains. Come December, a sherried dram beside the Christmas pudding is one of the great, underused pairings of the season: two versions of the same dried-fruit idea raising a glass to each other.

So when the clocks go back and the evenings close in, this is the bottle to have within reach. Sherried whisky is not a summer flirtation or a cocktail-hour crowd-pleaser. It is a slow drink for a dark night, built from the same casks that are quietly making sherry fashionable again. Pour it into the right glass, add a drop of water, and let autumn do the rest.

Some whiskies are for the sunshine. This one waits for the fire.