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Singly Malted
Barley is the source of our complex flavour
February 8, 2023 | ELEMENT: barley, life, steel | article | 10 minute read

Barley is our primary ingredient — the source of our complex flavour. Indeed its remarkable 2000 flavour compounds make single malt whisky the most flavour-complex spirit in the world.

But there is a vital word there that enables barley’s compounds to be fully expressed; the key, if you like, that unlocks barley’s flavour. We’re talking about malting. To be classified as a single malt whisky, all of our produce must be made from malted barley — unlike single grain whisky, for instance, which can be made from a mixture of malted and unmalted grains, or ‘single pot still’ whisky, made from a mixture of malted and cheaper unmalted barley.

Malting then. Unlike grapes or apples or sugar cane, barley cannot simply be fermented from scratch. It does not have the required direct sugar source. Instead, like all grains, it is a rich source of starch, which requires converting into soluble sugars in order to be fermented.


How to achieve that conversion? The answer lies with enzymes — α-amylase and β-amylase. Not only do these enzymes modify grain starch into maltose, maltotriose and maltodextrines. Further enzymes will, at a later stage in the whiskymaking process, break down proteins in the grain into forms which the yeast can act upon.

The process of malting unlocks those enzymes and barley, beyond all other grains, is especially good at producing them.

‘There are no other small-grain cereals that have the same enzyme power’, says our barley expert, Dr Dustin Herb. ‘That’s why barley has become this powerhouse in the whisky industry. Those enzymes, when they’re in the mash, can then move through the mash into other grains that are unmalted — with low enzymes — and actually start converting that starch into sugar’.

This is why even whiskies with a different primary grain — bourbon, rye, grain whisky — will almost invariably use an element of malted barley. Aside from its immense flavour complexity, it is a peerless enzymatic engine.


Barley has such enzymatic power that in Ireland, as in all of Europe and most of America, it requires a stage called ‘seed dormancy’ before malting. This is an evolutionary adaptation that shuts down the seed, preventing it from germinating and putting out seedlings. In Ireland’s intermittently wet summers, a lack of seed dormancy would lead to barley utilising its enzymatic power to recommence germination in the ripened seeds whilst they were still attached to the unharvested plant.

For this reason our barley cannot simply be taken straight to the maltings once harvested from each farm, but must make its way to its designated bay in our Cathedral of Barley, where it gradually dries and waits for seed dormancy to break — a process that can take well over six months.

The malting itself is a matter of artificially inducing that germination process.


Every batch size must amount to 100 tonnes of green barley. Individually, farm by farm, our barley, once awoken from its seed dormancy, will be taken to our dedicated 90-ton Boby malting plant at Minch Maltings in Athy (a fraction the size of a standard industrial malting plant, which reaches well into the thousands of tonnes). This plant is an unsung hero of our operation — indeed it is the great dictator of our whisky output. Since we need to fill it for every individual malting, every batch size must amount to 90 tonnes of barley. This is therefore the minimum required quantity from Single Farm Origins, as well as the director for every batch of whisky created at the distillery.

The first 38 hours are spent steeping in warm water — the means by which barley is ‘tricked’ into believing that the vintage cycle has begun again.

After a ‘rest phase’ to remove carbon dioxide which would otherwise kill the grain, a second ‘wet phase’ is induced to hydrate the barley to around 43-45% moisture.

It’s at this point that the barley is transferred to the ‘germination vessel’, where it literally grows for four days; humidified air ensuring that it retains required moisture content throughout. What’s taking place is a process of respiration; the barley taking in oxygen and releasing carbon dioxide as its internal constituents naturally modify themselves and enzymes begin to awaken.

This process is generally sped up by as much as half a day through the addition of an enzyme called Gibberillic Acid. Ever rebellious, we choose to eschew such additives, preferring our barley to work at its own pace, ’low and slow’; a little extra time taken perhaps, but no bad thing when one searches for natural flavour.

Like the stirrings of life, the warmed, moistened barley puts out chit — the little green shoots of artificial springtime — grains gently stirred by the maltsters to avoid those shoots becoming entangled, and to retain air flow between the grains. In the past, and in the rare instances that malting still takes place on a huge, wide ‘malt floor’, this movement was conducted by maltsters armed with shovels; an intensely laborious task that would ultimately leave long-serving maltsters with so-called ‘monkey shoulder’ — an overdeveloped, uneven hump of muscle and hunch in one shoulder.


When the four days are over, germination must be halted by a process of kilning; drying the barley to prevent shoots from growing further and starch from over-converting and reducing both yield and flavour potential. Since time immemorial this was done over a fire, fuelled either by wood or — in rural Ireland and Scotland — peat. It is this process that introduces flavours of smoke to the barley; until King Charles I granted Sir Nicholas Halse a patent for a new type of kiln-oven in 1635, all drinks produced from malted barley, be they beer or malt whisky, would have carried flavours of smoke.

Although we have re-introduced the flavours of Irish peat to Irish whisky, the majority of Waterford Whisky is unpeated; merely kiln-dried with hot air. Yet it would be a mistake to believe that this process does not impact flavour. Kilning is responsible for the final colour of the malted barley and, far more importantly, the degree of Maillard Reaction — the chemical reaction between amino acids and reducing sugars involved in any dry cooking process — that the barley undergoes.

Some malts, such as those used for dark beers, will be literally roasted for as much toast and colour as they can attain. Being more interested in the natural flavours of the barley and its terroir, we opt only for enough heat to dry our barley; a gentle toast only, to suit each variety and terroir and make the most of the characteristics each expresses.

Once dried, the malted barley — its enzymatic power and sugars now fully unlocked — can make its way to the distillery to begin the brewing and fermentation process.


The great advantage, to our terroir project, of the tiny scale of our maltings, is that we can afford not to take a ‘one size fits all’ approach. Given how different our farms can be, and how different the flavours of their barley are — even when planted with the same barley variety and on the same soil series —it’s no wonder that malting specifications need to be tweaked from batch to batch, to say nothing of the individual requirements presented by every different vintage. (2018, for instance, was challengingly high-protein.)

Be it for reasons of differing nitrogen or protein content or, especially in the case of our Heritage varieties, harder husks and smaller grains, the malting process — be it steeping temperature, water quantities or timings, or the heat and time in the kiln — needs to be adjusted for every farm, farming method and variety.

Absurd, if one’s aim is simply yield and efficiency. But to our mind malting is the key to barley’s natural flavour — and we want as much of it unlocked as possible.

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