What is Single Malt Whisky? – Rules, Production and Characteristics

What Defines a Single Malt Whisky?

Defining single malt whisky is simple. Single malt must be made entirely from malted barley and aged in wooden barrels for a minimum of three years and one day. Moreover, single malt must also be produced at a single distillery to earn the title. What this means for you is distinct malt expressions and end-to-end quality control.

• 100% malted barley
• Aged in wood for three years and one day
• Produced from a single distillery (aka. not blended)

In whisky production, the addition of different grains such as rye, corn or wheat, strongly influences the characteristics of the final product. Bourbon typically uses corn as the base grain. There is a huge diversity of exciting whiskies out there which use a variety of grain blends. There is no need to stretch the definition of what single malt whisky is; it’s aged spirit from 100% malted barley, produced from a single distillery – that's it!

Understanding single malt whisky is just as important as understanding what it’s not. Single malt whisky cannot be classified as Bourbon, or single-grain whisky.

Single malt is also never blended with whiskies from different distillers – it must all come from a single whisky producer. However, single malt is also not synonymous with single-cask whisky. Different cask expressions at a single distillery can be mixed together to create a Signature Single Malt Whisky.

Finally, producers of New World single malt whisky are not bound by the same rules and regulations that other appellations such as Scotland, and Ireland are. Producers such as Cotswolds Distillery have the unique opportunity of broadening the conception of what single malt is and the characteristics associated with it.

What’s Special About Single Malt Whisky?

Single malt whisky is generally perceived as the highest quality stamp associated with whisky. Because it uses only 100% malted barley and no other grains, the end product can be a direct expression of those malts, the barrels they age in and the production process of each distillery. Because single malt is from a single producer, there is typically better consistency and quality control, ultimately resulting in a precise and high-quality outcome. Many whisky drinkers also prefer the taste of malt whisky over grain whisky.

How is Single Malt Whisky Made and Matured?

To understand single malt, you need to learn about its production. Firstly, harvested barley is malted. This process activates and then halts germination to make sugars readily available. Sugars are needed in order for the yeast to produce alcohol.

Next the malt is milled and ground down into a grist which resembles coarse oatmeal. This grist is mixed with hot water to create a sugary, malty liquid called wort. Yeast is added to the worts to start fermentation in (typically) a stainless steel tank.

The fermentation mixture is left for several days until it creates beer – not one you’d want to drink but one that’s perfect for distilling. The beer is distilled twice in copper pot stills . Then you’re left with clear alcohol at around 75% abv.

Before the heart cut (distillate) is transferred into oak barrels for ageing we dilute it slightly to 63.5%. New World whisky production permits the use of various seasoned barrels - which have been previously used to age other things such as Sherry, Bourbon or even vermouth or rum. Whisky matures in barrels until the producer decides it’s ready for bottling. Single Malt must be aged for at least three years and one day.

Before bottling, liquids from different casks are often blended to create unique cask expressions. The whisky is also usually diluted to 40-50% abv., before bottling. However, cask-strength whiskies around 60% abv, are available.

Why is Single Malt More Expensive?

The same reasons that make single malt special also mean it can come at a higher price point. Generally, single malt is of a better quality and has nowhere to hide. The product directly reflects the consistency in production, the quality of the grain and the expertise of maturation and blending.

If you’re buying older bottles, it’s often more expensive owing to longer maturation. Malting barley also increases the costs of production.

Because of its superior quality and expressiveness, single malt whisky is typically the most desirable – the demand for quality warrants a premium price point.

Shop Single Malt Whisky from the Cotswolds

What Makes a Good Single Malt Whisky?

There are no defining characteristics of good whisky. Different types of single malt offers diverse flavours from, peat and smoke, oak and vanilla to sweet and fruity. However, the best approach when choosing whisky is to understand the tasting notes you prefer. Try and choose a whisky distillery that demonstrates quality at every stage of production. If you’re new to whisky, choose a well-rounded, accessible bottle which can express itself both mixed and neat.

Our ambassador recommends the Cotswolds Signature Single Malt

What is the Significance of the Age Statement on a Bottle of Single Malt Whisky?

Typically, we’re drawn to higher age stamps on a bottle of single malt – you’d assume it translates to boldness, smoothness and richness. But age is not directly indicative of quality or flavour. Age statements became more prominent following prohibition in the United States of America to re-establish the market and create a premium on surplus, ageing stock. Choosing the whisky with the longest maturation period is not always the best rule of thumb when choosing a quality product – especially in the New World.

When you mature whisky, typically in oak casks, the liquid takes on notes from the wood and exchanges with the environment. The longer it ages, the more the whisky complexifies. However, warmer climates, such as in Taiwan, Australia or Japan, emphasise this exchange of flavour and dynamism. Flavours intensify much quicker than in the cooler climates of Scotland and Ireland.

A simple way to understand this is by looking at the angels’ share. Some alcohol evaporates from the barrels during maturation, we call this loss in abv., the ‘angel’s share’. In Scotland, the angels’ share is about 2%. Whereas in the warmer climate of the Cotswolds, we lose around three times that (approximately 6%). The complexity of our liquid intensifies much quicker. We’re actually creating flavour profiles that mimic higher Scotch Whisky age statements in much younger bottles.

Frequently Asked Questions

How Should I Store My Single Malt Whisky to Preserve Its Quality?

The ideal way to store single malt whisky is at cellar temperature, just below room temperature (15-18°C), out of direct sunlight. Higher temperatures and UV exposure for long periods can alter the chemical composition, and ultimately, the tasting notes of your single malt.

How does the distillation process impact the flavour profile of a single malt whisky?

Distillation separates volatile compounds such as alcohol, fatty acids and fruity esters from heavier, rougher compounds. Our long fermentation “creates loads of fatty acids, esters and really oily compounds that create big flavours transferred through distillation...Through distillation, we try and retain those fruit flavours that we’ve created.” Our unique cut points ensure that we retain those flavour compounds in the final product.

Can a whisky be single malt but also blended?

A blended whisky that mixes output from different distilleries can’t be classified as single malt. However, single malt whiskies don’t have to originate from a single barrel, they can be blended from multiple different casks within a single distillery to create a distinct flavour profile.