The Impact of Production on Whisky Flavour
Whisky’s flavour is shaped by a meticulous production process, where every step—from malting and fermentation to distillation and maturation—plays a crucial role. While grain selection sets the foundation, factors like yeast strain, cut points, and cask type refine and enhance the final spirit.
At the Cotswolds Distillery, the focus is on crafting bold, flavour-packed whisky using copper pot distillation and extended fermentation, which ensures rich fruit and deep complexity. Maturation in carefully chosen casks further accentuates these characteristics, creating a whisky that balances tradition with innovation.
This article explores the science and artistry behind whisky production, revealing how fermentation generates key flavour compounds, how distillation refines the spirit, and how oak ageing shapes the final profile.
- The scientific art of single malt whisky production
- Factors affecting whisky’s unique flavour
- What flavours is The Cotswolds Distillery Known for?
Mastering the biology of malting & fermenting, the chemistry of distilling and the art of maturing & blending
Every stage offers a new opportunity for introducing or refining flavour
Rich, smooth, bold and fruity. Choose a flavour-packed single malt of the Cotswolds
The Scientific Art of Single Malt Whisky Production
Whisky production is a centuries-old craft, first documented in Scotland as the ‘water of life’. Whisky is made via the exhaustive process of malting (malt whisky), mashing, fermenting, distilling and maturing – every stage provides an opportunity for enhancing the whisky’s flavour and body. Conversely, it means yet another variable to control and perfect.
What's Involved in Whisky Crafting?
In essence, single malt whisky production involves harvesting, malting, milling and mashing premium local barley – we source ours from the heart of the Cotswolds. Next, hot water is added to the grist (barley pulp), creating worts, which is rich in sugars (think Horlicks). The sugary liquid is fermented with specially selected yeast strains, and the resulting ‘beer’ is then distilled.
The Cotswolds Distillery uses copper pot distillation to maintain the depth of flavour created during fermentation. After double distillation, the heart cut is ready for maturation in oak barrels.
The clear grain spirit fills seasoned oak barrels to age for at least three years and one day. It exchanges colour and flavour with the wood, developing a unique palate. Blending and finishing are common practices, but aren’t essential.
What makes whisky taste Like Whisky?
The main differentiator between whisky and other wood-aged spirits is the base starch. Whisky is made from grains; single malt is specifically made using 100% malted barley. Grain selection has an important influence on the flavour of the final spirit.
Secondly, the cask selection creates the characteristic flavour profiles of whisky. For example, Bourbon must be aged in virgin American oak. Meanwhile, single malt Scotch is limited to traditional seasonings such as STR red wine casks, Sherry casks or ex-Bourbon barrels.
Factors Affecting Whisky's Unique Flavour
What role does fermentation play in whisky flavour?
During fermentation, yeast creates a wide variety of organic compounds, including ethanol (alcohol), fusel oils, phenols, esters and aldehydes. Fusel oils, phenols and esters are all highly aromatic, contributing to the whisky’s scent and flavour. Some aromatics produced during fermentation are as follows:
- Alcohol: ethanol, methanol, higher alcohols (fusel oils)
- Esters
- Aldehydes
- Ketones
- Sulphur compounds
- Phenols
Why does fermentation time matter?
Lots of flavour develops during fermentation, so cutting it short limits the amount of flavour packed into the wash. On the other hand, leaving the liquid to ferment too long can compromise the overall ABV.
“When we’re doing that beer-making process, the industry standard is to ferment for 2 days, get it up to about 8%, then bang it in your stills. We leave it for an extra 2 days... what that does is it creates loads of fatty acids and esters and really oily compounds that create big flavours that can be transferred through distillation”
- Rob Patchett, Global Whisky Ambassador for The Cotswolds Distillery
How distillation fine-tunes flavour profiles
On initial inspection, distillation seems simple. However, there are many key and precise decisions to be made. Three crucial cut points determine which volatiles to keep and which ones to discard.
- The foreshots or the heads contain the most volatile compounds as they’re the first to evaporate. This contains lots of unwanted compounds such as aldehydes, methanol, light alcohols and acetone. The foreshots and heads are discarded so as not to spoil the all-important heart cut.
- The heart cut, as the name suggests, is what makes up the final distillate. It captures ethanol, esters, sulphur compounds, phenols and other aromatics. The earlier the distiller cuts it off, the fewer flavour compounds reach the final product.
- The latest cut is the tails or the feints. This cut determines which of the heavier, rougher compounds are discarded or kept. Lots of heavier oils, esters and tannins are the last to evaporate but contribute to depth, complexity and mouthfeel.
Cut Points Explained
Cut point decisions heavily influence which flavour compounds make it into the final whisky. Some distilleries prioritise earlier cut points for a lighter spirit. Others enjoy the richness associated with heavier oils, esters and phenols (Psst., that’s us at the Cotswolds Distillery).
How does the choice of still affect the final whisky profile?
There are two types of stills, pot (with bulbous bowl and a tapered neck) and column (with a less pronounced or no bowl and a tall, pillar-like column).
Copper pot stills are typically used for batch distillation, whereby a batch of liquid is distilled completely before stopping distillation and repeating the process for another batch. Batch distillation usually captures more flavour compounds and impurities. The liquid must be distilled at least twice to reach a suitable ABV for whisky. Irish whisky production rules outline that the liquid must be distilled a third time – this creates a light, crisp and clean spirit.
On the other hand, column or Coffey stills are used for continuous distillation, whereby, new liquid is continuously fed in and condensed out. It separates different groups of volatiles but usually results in a much ‘cleaner’ spirit at a higher proof. Column distillation results in a milder flavour profile that relies more on barrel maturation for flavour generation.
We value bold flavours at the Cotswolds Distillery, which is why we use batch distillation on copper pot stills – our award-winning distillers have ultimate control over cut points and flavour profile.
“We’re not creating a spirit where the flavour needs to be created by the wood but creating a spirit that is really fruity grappa/eau de vie-style that can be accentuated by the barrels. We’re already pre-loading flavour in production so the barrels can just add more flavour”
- Rob Patchett, Global Whisky Ambassador for The Cotswolds Distillery
The crucial role of whisky maturation
The flavour-packed heart cut is transferred into specially selected oak barrels for maturation in the Cotswolds. We utilise delicious barrel seasonings, such as Pineau des Charentes, Banyuls, premium Sherry, or Bourbon barrels. Single cask expressions may spend time in just one barrel type or be ‘finished’ in another. The most common approach is to blend single malt from different cask types.
Read about the influence of cask selection on whisky flavour
What Flavours is the Cotswolds Distillery Known For?
The founder of the Cotswolds Distiller, Dan Szor, envisioned a single malt whisky that marries bold fruit-forward flavour profiles with delicate precision and smoothness.
“[Dan] said three things: ‘I want to make a whisky I want to drink, in a distillery I want to visit and in an area that I love’”
“you want to make sure every element is done with credibility, and that’s what the signature is - there are no corners cut. It’s absolutely outstanding and the way whisky should be”
- Rob Patchett, Global Whisky Ambassador for The Cotswolds Distillery
He created just that in the Cotswolds Signature Single Malt. It’s packed with tropical fruits, honey, red fruits, citrus, orchard fruits, treacle and a hint of toasted almonds. This versatile single malt appeals to whisky novices and die-hard Scotch fans alike.
While the signature spirit represents the spirit of the Cotswolds, there is a world of flavour to try from the Peated Cask Single Malt, The Founder’s Choice STR Casked Single Malt or a Bourbon barrel expression. They all use our unctuous recipe, brimming with aromatics.
Frequently Asked Questions
Do all distillers use the same yeast strain?
Most brewers and distillers use similar yeast strains for their consistency and appealing flavour. We use anchor and fermentis yeast, which create those fruit-forward flavours that we love.
“The clear worts [fewer grain fragments] and long fermentation create big fruit - it just smells like banana bread and pineapple, it’s amazing”
- Rob Patchett, Global Whisky Ambassador for The Cotswolds Distillery
How do whiskey mash bills impact the flavour of the whiskey?
The mash bill basically means the grain proportions used. Malt creates a rich, smooth and complex profile; rye adds spicy elements. Meanwhile, corn and wheat offer softer aromas. Read about grain selection.
How important is terroir in whisky production?
In the wine industry, growing conditions in the vineyard translate into the wine’s final characteristics. The same pattern has not yet been proven for whisky because the distillation process leaves behind most of the tannins and organic matter. However, regional differences in flavour profiles could indicate that the surrounding environment has a part to play.
Does higher proof whiskey taste better?
Higher ABV whisky doesn’t necessarily taste better, especially if it comes off column stills with a lighter flavour profile. The ethanol burn can easily overshadow the delicate aromas, which is why most producers dilute cask-strength whisky to a balanced 40% ABV. You’re always welcome to dilute it further to your liking.