Whisky making is not about following a formula. It’s about creating a whisky full of character and flavour. It’s about recipe and how it’s worked, interpreted, played with. It’s about maths and science, yes, but also it’s about accident and surprise, about intuition, feel and flow. Elemental and natural, yet technological and crafted, it is a sometimes heated, occasionally languid, and often drawn-out conversation between grain, water, copper and wood, as facilitated by the distiller, and by the world of the distillery itself.
MAKES AND FLAVOURS
Distillers have known for long before science began to explain why that the distillate or ‘new make’ is not, in the truest sense, a neutral spirit, that it holds flavour, and that the type and extent of that flavour depends on some or all of the choices made at key stages of the process. We’re making a spirit that tastes of the distillery that gave birth to it. That’s personality.
In the first instance, such a personality begins with the grain. As well as possessing their own specific taste profiles (see The Flavours of Grains), grains are deliberately imbued with flavours, all of which are designed to survive and influence the fermentation and distillation processes. To this end, a distiller may roast or peat the grain. Owing to the reductive effect it has on starch levels, and therefore on yield of alcohol, roasting is reasonably rare: in terms of how it enhances flavour, it’s all in the name. Peating, meanwhile, is practised in the making of some malt whiskies, and as such is a fine example of necessity being the mother, with the decomposed vegetation that makes up peat bogs all that was available when it came to finding fuel to burn and so dry out the malt. The science behind the effect unbeknown to early maltsters, peat smoke (‘reek’) contains vaporised oils, certain chemicals (phenols) of which re-solidify on contact with the husks of the still damp, malting barley. The process gives the final whisky its characteristic smoky overtones.
This deepening and developing of personality continues on through the mash and into fermentation, the magic that sees sugar converted to alcohol being also a magic that is all about the creation of flavour. As well as making ethanol, which has no flavour, fermentation gives birth to various hyper-powerful flavour compounds or ‘cogeners’, of which there are four main types: acids, esters, aldehydes and higher alcohols. Mere trace elements, these cogeners are formed at various stages of the fermentation, and are responsible for the wash’s overall fruity flavour. The shorter the fermentation, the more cereal notes carry through to the wash. The longer and cooler the run, the fruitier it gets, the caveat being that the tail end of the process is vulnerable to bacterial growth, some good, some not so good. Further, sulphury flavours are as much a by-product of fermentation as fruit esters, and can, if allowed, taint the wash. A select few are desirable; all are not.
Each of the four main whisky-making grains comes with its own unique bundle of flavours.
Generally speaking, malted barley will give the new make a biscuit-like taste, a soft-baked depth that will, if allowed, survive into and be complemented by maturation. Unmalted barley, meanwhile, comes over as all peppery and oily and sharp fruit. Corn is sweeter than barley, its high starch content translating as a bass-like fatness. Rye is the devil in a bespoke tweed suit, a hot citrus-based chutney in hand-stitched boots. Wheat’s the boxer of the bunch, beautiful and intelligent, light and honey-footed, its punch well-executed, not an ounce of wasted energy. As well as the four main whisky-making grains, other grains variously and occasionally used include spelt, millet and oats – so-called pseudograins like buckwheat and quinoa too. All impart their own specific flavours.
As well as sourcing different types of grain, a growing number of distillers swear by individual varieties, arguing for flavour over yield. When mixed, and at different ratios, the grains create new flavours. The different mashbills used in the making of bourbon are a perfect example of this. A bourbon mashbill consists of a majority portion of corn, a percentage of normally rye and about 10% malted barley. In some bourbons, the rye is substituted for wheat. If a ‘high rye’ bourbon, then the spice is very evident, though the quality of the making means the corn’s weight ought to balance and soften the fire. If low, then the bite’s much more subtle, the corn’s sweet butter-like fullness welling up beneath. If a wheated bourbon, think light, smooth, honey, the corn a double sugar hit.
Some distillers are happy to share their mashbill ratios, others are not!
The jury’s out as to whether copper actually creates flavours, with some arguing for its role in the appearance of certain unseen esters. No doubt, however, as to the efficacy of copper’s ability to strip, through direct contact with its vapours, the spirit of heavier and usually unwanted flavours – sulphuric, meaty and, to a lesser extent, feinty notes.
In this respect, the longer the contact between copper and vapour, the lighter and more elegant the spirit; the shorter the contact, the heavier and more endowed with character it is. Think flowers and perfumed oils versus sulphur and meat. The shape, design and use of the stills help decide the length of contact, and therefore the character of the spirit.
CUTTING TO TASTE
Whatever the grain and how it’s been treated, whatever the success of the creation of new flavours during the mashing and fermentation processes, I can’t stress enough how easy it is for a distiller to lose, destroy or taint flavour during distillation.
Most of the spirit run – its head and tails, or foreshots and feints – is either poisonous or foul-tasting, and will be recycled back into the next wash. The size of middle of the run, the part worth holding onto, will depend entirely on the distiller and what kind of whisky he or she is after. Cogeners are very well-behaved. They respond to temperature, and vaporise in a set and strict order: lightest first, heaviest last. The lightest are very floral, grassy and green. The middleweights are all fruits, the lightest of these crisp and fresh, the heaviest red, soft, ripe and even stewed. As the heaviest cogeners come into play, so the fruit almost rots off, making way for cereal and smoke, the oils and tar.
Which of these the distiller picks, and which he or she lets go, will depend on flavour objectives. An early first cut picks up the flowers; a late first cut, more fruit than flower. If looking for flower and fruit, but steering clear of the heavies, then the second cut needs to be made before the appearance of the smoke. If after a full-blooded fruit with plenty of smoke, then it’s a cut towards the middle and a late finish. If after the whole spectrum, then early and late, though with great care – a feinty-tasting new make is a potentially off-tasting whisky.
Crucially, the run decreases in levels of ethanol. More ethanol means fewer flavour cogeners. The earlier the cuts, therefore, the higher the new make’s level of alcohol content, and so the less it will retain flavours gained in the mash and during fermentation.
THE MIRACLE OF OAK
However important it is in terms of contributing to flavour, it is during its years spent in wood that the new make actually becomes a whisky. Many a distiller believes oak – almost always oak – contributes to 70% of the final article, its flavour, its balance, its overall structure.
Hear this: in the land of flavour making, the cask is king, its position earned for the extraordinary role it plays in maturing the distillate, which it does either by adding or removing flavours in three distinct ways: extraction, evaporation and reaction.
The spirit in a barrel is never still. Rising ambient temperatures cause the liquid to expand, pushing into the wood, variously dissolving and decomposing its sugars, tannins and simple flavour compounds. As ambient temperatures decrease, so the spirit turns in on itself, contracts, and draws or extracts the wood’s caramels, colouring and flavour compounds into itself. Expanding and contracting – year in, year out – the spirit rhythmically feasts on the barrel, though most fiercely in the first year.
At the same time, changes brought on by this interaction with the wood are compounded and aided by the process of evaporation, a phenomenon popularly known as the Angel’s Share, with sharp- and bitter-tasting sulphides expelled suddenly, in the first month, and then gradually over time. The exiting gas is replaced by fresh oxygen, which acts as vital catalyst for the oxidation of ethanol into further flavour making chemical reactions. In this way, barrels can be said to breathe – through gaps in the joins and the bung hole.
Finally, as time passes, facilitated by oxygen, water and ethanol, a complex chain of reactions will occur between various wood chemicals in themselves, between the certain wood and spirit chemicals, and between specific components of the spirit itself, all of which eventually amounts to sour, off-smelling aldehydes turning into more pleasant acids, which in turn are converted into a range of flavoursome fruity esters, the final outcome being, hopefully, a deep and finely balanced package of flavours.
YOUR CASK, SIR
Distillers’ approach to wood source, to the cooperage and lifespan of a cask, borders on the manic obsessive. Today, whisky casks are a made-to-order phenomenon.
It’s a mania that takes many forms, from tracking the oak from source to final cask, to insisting on the wood from a particular part of the tree, to most precisely selecting the tightness of grain, but the most radical piece of cask tailoring will be the decision as to whether to toast or char, or both – and at what level.
Toasting and charring are the application of thermal heat to the layers of the wood on the inside of the barrel, thereby breaking down its structure and creating flavours that are released into the spirit during the early stages of maturation. Toasting is as it sounds: toasting. It is not direct fire and lasts 15–45 minutes, at temperatures of between 100 and 200°C. Charring, meanwhile, is toasting gone spectacularly wrong. It’s direct. It’s much hotter. The barrel’s innards are actually set alight, for a matter of seconds, the result a charred surface, black and pitted like a crocodile’s skin. However, despite the extra heat, there’s less penetration than a toast – think of the difference between burning and toasting a piece of bread.
As with grain, so the type of oak chosen will help determine certain flavour profiles. Depending on length and quality of the maturation phase, American white, the most commonly used oak, gives its whiskies the taste of vanilla and coconut, of honey and toffee, of red fruits, ginger, almonds, the scent, eventually, of tobacco and leather. If European oak, then there’s lots of tannin, of fruit cake, of cinnamon, clove, caramelised orange, the rich smells of a kitchen come Christmas pudding time. French oak, meanwhile, is similar, though imparts extra spice, while the much rarer Japanese oak, as well as inhabiting a cross-section of the above, comes with a whole bunch of extra acid fruits, as well as an added incense-like spiciness.
Before being made up into casks, all oak needs drying out or seasoning. Properly seasoned wood makes a real difference to flavour. Yard drying oak takes years, and happens outside. Exposed to the vagaries of season and weather, rot sets in, the various and successive colonies of fungi that make the wood their home taking root, and with it the formation of hydrogen peroxide, which as your hairdresser will tell you is a catalyst for chemical change, the sum of which, in the case of oak, serves to soften the tannins and unlock the wood’s sugars.
The overall effect of both reduces tannins, and therefore tightness of mouthfeel in the whisky. It also caramelises sugars and releases vanillin. The charred layer has the added effect of filtering impurities during maturation, while the extra heat is enough to generate the appearance of various phenols, especially clove-like aromas and notes of smoke.
Depending on his or her strength of new make, on the degree of filter required, on the depth the wood needs penetrating, a distiller can opt for a light, medium or heavy toast, and for one of at least five grades of char. There’s a lot to think about.
WORK THAT CASK
Whatever the type of oak, a virgin cask makes for an immediate and powerful wood influence. If, therefore, like bourbon makers, legally committed to always using new casks, a distiller may either take the spirit off the stills at a lower strength or dilute the barrel entry strength – in order to slow down the rate of extraction. By the same token, a distiller may use a fresh cask to flush more tannin, or a certain sweetness, or vanillas, into a bull of a spirit.
Meanwhile, a used cask – ex-bourbon, sherry, cognac or wine – is valued for how the original liquid’s years of interaction with wood will influence the taste of the distillate, and for the fact that the strength of influence of the used wood diminishes significantly with every reuse – perfect, then, for fragile, light spirits, which would otherwise be overwhelmed by the wood.
Distillers may then choose to move the spirit into different casks, either as a means of nursing a poorly maturing whisky along or in search of more flavour. As is increasingly the case, a distiller might choose to ‘finish’ a nearly matured whisky in a different type of used cask. Thus an ex-bourbon cask matured whisky will get a finish in a sherry butt, or in a wine cask, or a port pipe, the aim being to give the whisky a final layering of flavour, an element of character that it will not have got from the previous cask.
DANCING WITH ANGELS
If indeed the cask is king, then its palace is the warehouse, and one that has enormous impact on rates of maturation – and therefore on flavour. It’s an ageing tool in its own right.
DUNNAGE OR RACKED
There are two main types of warehouse: dunnage and racked. The dunnage warehouse is the romantic’s version of what a warehouse looks like, the racked a beancounter’s ledger, a place where function rules. Actually, they’re both beautiful, the former damp and low, sweet-smelling and dark, the latter, however financially expedient, paying unexpected homage to the architecture of the industrial revolution, styles that have over the years acquired a certain brutal grace – dark and silent halls, cathedrals of liquid gold.
In deciding on cask type, its particular levels of customisation, as well as on what strength to barrel at, the distiller needs to account for the effects of temperature and humidity on annual rates of evaporation. The angels will have their share, though how big, and exactly what the nature of their tipple, will depend not only where in the world the cask is stored, but also its spot in the warehouse.
A cask, then, can lose on average anything from 2–12% of its liquid annually to evaporation. In maritime climates like Scotland or Ireland, where temperatures are low and humidity is high, the loss is more in alcohol than water. The reverse is true of hot, dry countries.
There’s more. Individual warehouses come with their own microclimates, whereby ambient conditions – temperature, light, airflow and humidity – are affected by position and height, and by the materials the warehouse is made of. Easier to manage, the single-floor dunnage warehouse is less variable in terms of how it influences maturation.
By contrast, the ambient conditions of a racked warehouse will vary between the first and the twelfth rack, and considerably more between the ground and top floors, a factor well understood by distillers and warehouse managers, who speak of sweet spots, strength fill casks according to loss prediction and operate warehouse policies that rotate casks through the levels, or favour different warehouses for different whiskies.
There are attic angels and there are ground floor angels and there are many angels in between. The distiller must dance with them all.