More Drams, Less Drama - Coldorak's Whisky Blog.

Fermentation: Where Whisky Gets More Than Just Alcohol

28th October 202627th October 2026Coldorak

Yeast, wild microorganisms, esters and the chemistry behind whisky’s fruity flavours.

Whisky is made from grain, water and yeast. Ask what yeast does, and the usual answer is straightforward: it converts sugar into alcohol. Technically correct, but rather incomplete.

Fermentation is also responsible for producing many of the compounds that give whisky its fruity, floral, cereal and sometimes rather unpleasant aromas. Long before the spirit encounters a copper still or an oak cask, much of its aromatic foundation is already taking shape.

And while distilleries love to talk about long fermentations, special yeast strains and tropical fruit notes, the relationship between fermentation and flavour is considerably more complicated than the marketing might suggest.

So what actually happens inside a washback? Does a longer fermentation really mean a fruitier whisky? And could the wild microorganisms living in a distillery be just as interesting as the yeast deliberately added to its wort?

The Copper Paradox: Why Whisky Needs Copper, But Not Too Much

26th October 202625th October 2026Coldorak

Sulphur, still shapes, worm tubs and the chemistry behind one of whisky’s most misunderstood ingredients.

Walk into almost any malt whisky distillery and you’ll see those magnificent copper pot stills, often polished to perfection. They’re beautiful, traditional and essential to the character of the whisky. But not necessarily for the reasons you hear during a distillery tour.

Copper isn’t just a convenient material for making stills. It actively influences the chemistry of distillation, particularly the sulphur compounds responsible for aromas ranging from rotten eggs and cabbage to meaty and savoury notes. Without sufficient copper contact, whisky can taste very different.

But if copper removes undesirable sulphur compounds, why don’t distilleries simply maximise copper contact? Why do some deliberately produce heavier, more sulphury spirits? And why can copper sometimes contribute to the formation of sulphur compounds rather than removing them?

Welcome to the copper paradox.

A Cognac warehouse with casks and demijohns

When Does a Cognac Stop Ageing?

21st October 202620th October 2026Coldorak

Oak, demijohns, age accounts and the surprisingly complicated lives of very old eaux-de-vie.

Imagine two Cognacs made from grapes harvested in 1950 and bottled in 2025.

The first was distilled during the 1950–1951 distillation campaign, spent approximately thirty years in oak and was transferred to a glass demijohn around 1980. The second, produced during the same campaign, remained in oak until shortly before bottling.

Both come from the 1950 harvest. Both were bottled seventy-five years after that harvest. And both might be described, at least conversationally, as seventy-five-year-old Cognacs.

But are they really the same age?

In terms of the time elapsed since the harvest, yes. In terms of oak maturation, absolutely not. And in terms of how they taste, there’s no guarantee that the second will be more mature, more complex or even better.

This is one of the most interesting peculiarities of very old Cognac. We tend to treat age as a simple number, when it can describe several quite different things. And to complicate matters further, the year displayed on a Cognac bottle isn’t necessarily the year the eau-de-vie was distilled.

So when does a Cognac actually stop ageing? When it leaves the cask? When it enters a demijohn? When it is bottled? Or does it never completely stop changing?

The answer depends on what we mean by ageing.

Boisé, Sugar and Caramel: What’s Really in Your Cognac?

19th October 202617th October 2026Coldorak

Three permitted adjustments, a few persistent misconceptions, and a rather uncomfortable question about transparency.

Cognac is made from grapes, distilled twice in copper pot stills and matured in oak. Simple enough. But what happens between the cask and the bottle isn’t always quite as straightforward as the romantic descriptions of centuries-old traditions might suggest.

Unlike what some enthusiasts assume, Cognac regulations allow certain adjustments involving sugar, caramel colouring and oak infusions, commonly associated with boisé. None of these automatically makes a Cognac inferior. But they can influence its appearance, texture and, potentially, its flavour. And you won’t necessarily find them mentioned on the label.

So what exactly are producers allowed to add? How do these adjustments work? Can we detect them by tasting? And should we care?

Let’s look at what’s actually permitted, what it can do to the liquid, and why the distinction between traditional craftsmanship and unnecessary manipulation isn’t always as obvious as we’d like.

Rancio: The Most Overused Word in Old Cognac?

16th October 202615th October 2026Coldorak

Walnuts, mushrooms, old leather and the chemistry behind one of Cognac’s most mysterious characteristics.

There are a few words that seem almost compulsory when describing very old Cognac. Rancio is one of them.

Open a sufficiently old Grande Champagne, find some walnuts, mushrooms, leather or old furniture on the nose, and sooner or later somebody will mention rancio Charentais. Preferably with a suitably reverential expression.

And I understand why. Some of the most extraordinary Cognacs I’ve tasted have displayed precisely those characteristics. That combination of old wood, dried fruit, earthy notes, nuts and remarkable aromatic complexity can be fascinating.

But what exactly is rancio? Is it a particular aroma? A collection of aromas? A chemical reaction? A stage of maturation? Something that only appears after several decades in oak? And perhaps more importantly, are we sometimes using the word simply because the Cognac is old and expensive?

Let’s investigate.

What Your Cognac Label Tells You. And What It Doesn’t.

14th October 202614th October 2026Coldorak

From XO and Grande Champagne to Lot 75, vintage Cognacs and brut de fût: how much can we really learn from a bottle?

Independent (and sometimes official) Scotch whisky labels can be remarkably informative. Distillation dates, cask numbers, wood types, outturns, bottling strengths… sometimes there is so much information that you almost need a magnifying glass.

Cognac labels can be a rather different experience.

One bottle proudly announces that it is an XO. Another says Hors d’Âge. A third gives us a precise vintage, while another simply says Lot 75. Some mention Grande Champagne, others Fine Champagne. One is bottled at 40%, another at 54%, and both may contain eaux-de-vie that have spent decades in oak.

And somehow we’re supposed to compare them.

The problem isn’t that Cognac labels tell us nothing. They can tell us quite a lot. It’s that what they guarantee, what they suggest and what we assume they mean are three different things.

So let’s decode them.

Single Malt Is a Blend. And Single Cask Isn’t Quite What You Think Either.

12th October 202613th October 2026Coldorak

Single malt is supposed to be the opposite of blended whisky. Except that your favourite single malt may contain whisky from dozens – or hundreds – of different casks, vintages, ages and cask types, all combined to create the final bottle. Meanwhile, even single cask doesn’t necessarily mean quite what we instinctively assume. So what does single actually guarantee, and why is the whisky world so reluctant to admit that making a great single malt involves an awful lot of blending?

What Does ‘Refill Cask’ Actually Mean?

9th October 202613th October 2026Coldorak

There are whisky labels that appear to tell you almost nothing, and others that seem extraordinarily precise. Refill sherry hogshead certainly belongs to the second category. Three words, and apparently we know the cask. We know its size – or at least its general format. We know something about what it held before. And we know that it has been used before.

Easy.

Except that we still don’t know what kind of oak it is. We don’t necessarily know what kind of sherry was involved, how long it held it, how long its previous whisky maturation lasted, whether this is its second Scotch fill or its fourth, whether it was rejuvenated somewhere along the way, or exactly how active the wood remains.

Suddenly, ‘refill sherry hogshead’ doesn’t look quite so precise. So what does refill actually tell us? And perhaps more importantly, what doesn’t it tell us?

The Hidden Distillery: The Language of Undisclosed Whisky

7th October 202613th October 2026Coldorak

Independent bottlers are usually associated with transparency. They tell us the vintage, age, cask number, cask type, outturn, and strength, sometimes even the exact dates of distillation and bottling. In some cases, an independent bottling tells you considerably more about the whisky than an official bottle from the same distillery. And then, occasionally, it tells you almost everything except where the whisky was actually distilled.

Secret Speyside. An Orkney Distillery. An Islay Single Malt. Secret Highland. Williamson. Westport. Wardhead. Burnside.

Sometimes the distillery is genuinely difficult to identify. Sometimes everybody in whisky seems to know what it is, while nobody involved in selling the bottle will actually write the name down. And sometimes what looks like an undisclosed single malt isn’t legally a single malt at all.

Welcome to one of the stranger languages of independent whisky.

They Don’t Make Whisky Like They Used To. Literally.

5th October 202613th October 2026Coldorak

‘They don’t make whisky like they used to.’ It’s the sort of thing whisky enthusiasts like to say after tasting an old bottling, usually followed by something about wax, tropical fruit or an elusive ‘old-school’ character. Taken literally, though, they’re right: whisky really isn’t made exactly as it used to be. Raw materials, production methods, casks and bottling practices have all evolved, while the liquid in those old bottles has sometimes spent another half-century sitting behind a cork or screw cap. So when an old bottling tastes noticeably different from its modern equivalent, what exactly are we tasting – and can we really know why?