Bourbon Whiskey Flavours – The What and the How

Most of the Bourbon Whiskey Flavours come from the charred oak barrels it ages in

Born and raised in the USA, Bourbon Whiskey is one of the higher American spirits. Usually sweet, with vanilla notes, lightly smoky and with a waxy or oily mouthfeel, Bourbon Whiskey flavours are quite complex and acquired throughout the whole production process.

From the mashbill to how much charred is the oak barrels in which a Bourbon will age, every single step of the process influences the bourbon whiskey flavours. And, although there are norms that regulate how can Bourbon be made, these flavours can change depending on the kind of Bourbon one is drinking.

Before getting to what does bourbon taste like or how do a certain flavour note get in the spirit, we should sum up the norms after which a spirit can be called Bourbon Whiskey:

  • Although most Bourbon distilleries are located in Kentucky, this spirit can be produced anywhere in the USA (but not in another country).
  • It has to be made from at least 51% Corn. Other cereals might be added as the producers want.
  • Bourbon must be distilled at 80% ABV (160 proof), never more than that.
  • When its time for maturation, it must enter the barrels at a maximum of 62,5% ABV (125 proof)
  • When bottled, Bourbon must have a minimum of 40% ABV.


Table of Contents – Sip this Article

  1. What does Bourbon Taste Like?
  2. Bourbon Whiskey Flavours by Production Stages
    1. The Mashbill Components
    2. The Yeast Influence
    3. The Distillation Contradiction
    4. The Charred Oak Barrels Reaction
  3. Flavoured Bourbon Whiskey – Is it Really Bourbon?
  4. Final Thoughts


Different bourbon expressions have different bourbon whiskey flavours
Different bourbon expressions have different bourbon whiskey flavours.


What does Bourbon Taste Like?

Bourbon is a complex spirit, and it is possible to detect dozens of flavour notes while sipping it. However, like any other spiritual alcoholic drink, it is also possible to define a general character regarding the most standardized bourbon recipe – that is, according to the legal norms that regulate bourbon production.

So, if we have to determine bourbon whiskey flavours, those would be mostly sweet, with vanilla, caramel, honey, maple and butterscotch notes.

But, as said before, bourbon is a complex spirit and sweet flavours are not the only ones existing. It is also possible to find floral, fruity, smoky, and baking spices flavours. These can range from rose petals, light smoke, red pepper, cinnamon, and cardamom, for instance.

All these flavours – and many others detectable in different expressions – are acquired in different stages of bourbon production process, from the mash to the moment the liquid is put to age in a charred oak barrel, and even the alcoholic content right after distillation.


Bourbon Whiskey Flavours by Production Stages

Each and every stage of the Bourbon production process adds a little bit of flavour to the dram you’re probably sipping (or wishing to sip) while reading this article. This process can be divided into 4 steps: Mashing, Fermentation, Distillation, Maturation. And, depending on the choices of the producers on each stage, the flavours will develop differently.

Also, there are stages that provide a lot more flavour than others. For example, the cereals used to create the mash will provide the core profile of the spirit and the fermentation might create more subtle notes. However, it is the charred oak barrels and the maturation stage that provide bourbon the most of its flavour.

three barrels of bourbon whiskey


#1 – The Mashbill components

As you can imagine, each bourbon brand has its own recipe, and the mashbill ingredients may vary from bourbon expression to bourbon expression. However, there are norms that regulate how can bourbon be made. In this sense, part of the recipe can differ, but not the main cereal used in the mash. To call a spirit Bourbon, it must have at least 51% of corn in the mash.

Besides the corn, a bourbon may have other cereals in the mix such as rye, wheat and malted or unmalted barley in the mashbill. Each cereal will provide a different flavour to the final product and, being corn the main ingredient, that will be the background of all the bourbon whiskey flavours.

Also, when a Bourbon is aged for only a couple of years it is called grain-forward bourbons. That means that most of the flavours come from the cereals themselves and not from the wood, as it was expected.



As corn is the main ingredient, it will provide the most of bourbon whiskey flavours in comparison to other grains. It will provide the sweetness that bourbon has in its core, but it can also provide a creamy texture.



Rye is another usual grain in a bourbon recipe. It occupies between 10% to 30% of the mash, and, if an expression has more than 20% of the cereal in it, that bourbon might be called “High Rye Bourbon”. This grain will influence the spicier flavours of this spirit, similar to baking spices, such as cinnamon, nutmeg, black pepper or/ and clove. It can also bring some herbal notes to the expression.

The rye is also responsible for creating a dryer texture on the bourbon.

Rye, one of the cereals often used in Bourbon's mashbilll
Rye, one of the cereals often used in Bourbon’s mashbilll.



As it happens with bourbon, wheat will occupy a smaller percentage of the mashbill of 10% to 20%. It is usually used as a softening agent on a bourbon whiskey recipe since it is much smooth in flavour than rye or corn.

With this softer cereal, the bourbon will get aromatic and fruity undertones, but also light honey flavour notes. Regarding the texture of the bourbon, a strongly wheated bourbon whiskey (with more than 15% of wheat in its composition) may have a creamier texture.



Malted or unmalted barley is also used on the Bourbon mashbill in a small quantity. Especially malted barley can occupy from 5% to 12% of a bourbon recipe, and that happens because it can easily turn the starches to sugar.

Because it takes up a small space on bourbon mash, barley develop into subtle flavours such as light chocolate, nuts, and a hint of sourness.


#2 – The Yeast Influence

If you think yeast only converts the sugars present on the mash to alcohol, you might be underthinking the power of yeast. This single-cell organism is one of the most important part of bourbon production. Besides the feeding on the mash’s sugars, it helps releasing carbon dioxide and building the primary Bourbon Whiskey flavours.

Depending on the yeast strain a brand uses, this organism will have a direct effect on a bourbon expression’s flavour notes. When yeast is helping to ferment the mash, it produces chemical compounds called esters. These have a delightful smell and will help form the background aromas of the bourbon, as well as flavours.

The esters will contribute to form floral and fruity aromas, sour and grassy flavour notes.

Yeast can also have an influence on the texture of the Bourbon whiskey, making it buttery, oily or waxy.

The fermentation of the mash will also have influenece on Bourbon whiskey flavours
After the yeast being added to the mash, the fermentation stage begins. In this stage, some Bourbon whiskey flavours are created. Some of them remain, others are eliminated by distillation.


#3 – The Distillation Contradiction

Distillation is the final step that contributes to form the primary bourbon whiskey flavour. This contribution, however, might not be the one you think it is. Distillation will act on the flavours one does not want in a bourbon whiskey: excess sourness, earthy flavour notes, among others. Also, the stills used on distillation will influence the flavours that persist on the whiskey.

However, this part of the process will have its most influence on the mouthfeel of this spirit. If the spirit comes out of the distillation with -80% abv, its most likely it will turn out to be a oily and waxy bourbon.


The Charred Oak Barrels Reaction

As it happens with any other spirit beverages, bourbon whiskey gets at least 50% of its flavours from wood. In this case, from Charred Oak Barrels. One of the norms that regulates Bourbon’s production is the use of brand-new oak barrels to age the whiskey. Also, this wood must be charred, and the spirit must sit on these barrels for at least 2 years.

The longer a bourbon sits on the barrels, the more flavour the expression will take from the wood. Bourbon whiskey can take out flavours like nuts (almonds, pecans, walnuts), wood-like flavours, vanilla and caramel, clove, and even more tannic flavours, such as tobacco.

Firstly, we have to consider the type of oak that is used. For bourbon, it must be used American Oak, obviously. This wood will provide the spirit the lipids and the cis or trans oak lactones (another kind of ester), that are responsible for adding part of the vanilla flavour so characteristic in Bourbon Whiskey. It can also add some flavours similar to coconut and spices (being that this last one comes from a macromolecule called lignin).

Secondly, we have to consider the charring process of the oak barrels. The heat present while charring helps evaporation any water and releasing sugar from the wood. That will give the Bourbon a warm and buttery character.

This process will have influence in many Bourbon Whiskey flavours since it is responsible for creating phenols. These phenols, by their turn, will become the aromas and flavours inherent to this spirit. For instance, a phenol like vanillin will add tons of vanilla flavour to a bourbon expression, and guaiacol creates smoky and woody flavour notes. Eugenol is responsible for flavours such as clove, wood, spices, and other sweet notes, and vinylguaiacol will clove flavour to the spirit.

Thirdly, it is important to look at how much is the barrels were charred. The more charred the oak is, the more smokey the Bourbon whiskey flavour will be.

Most of the Bourbon Whiskey Flavours come from the charred oak barrels it ages in
Most of the Bourbon Whiskey Flavours come from the charred oak barrels it ages in


Is Flavoured Bourbon Really Bourbon?

From Straight Kentucky Bourbon Whiskey, we jump to a debate that has been troubling all bourbon whiskey drinker’s community – is flavoured bourbon whiskey really whiskey?

Flavoured whiskies have been rising in popularity for the last years, giving that younger generations are demanding differentiating products rather than just consuming what has been made for centuries. This led bourbon brands to adapt to the market and several of them already launch batches of flavoured bourbon, such as Wild Turkey Spiced, Jim Beam Peach and Knob Creek Smoked Maple Bourbon Whiskey. This on the rise market also brought up new, young brands just focused on producing flavoured Bourbon Whiskey, such as Misunderstood Whiskey (Ginger and Spice Whiskey), Screwball (Peanut Bourbon) and Bird Dog (with endless options of flavoured whiskeys).

While some of these brands do not market their product as bourbon, others have a reputation for producing non-flavoured bourbon and, therefore, the flavoured product ends up being perceived as such.

The debate around flavoured whiskey goes actually beyond the question “is it true Bourbon”, since the regulations on this spirit do not allow added flavours. This means that, in truth, flavoured bourbon cannot be sold as bourbon.

So, why is it associated with bourbon? As it happens with other flavoured drinks or cocktails, Bourbon Whiskey is an actual ingredient of the recipe. Depending on the brand or the batch, it might contain any kind of bourbon, just one flavour or a combination of flavours. One thing is for sure, sweetener is definitely a part of the recipe and it might come in big quantities.

Misunderstood whiskey is a btand of flavoured american whiskey made with bourbon.
Misunderstood whiskey is a btand of flavoured american whiskey made with bourbon.


Final Thoughts

When it comes to Bourbon whiskey flavours, complexity is the keyword. Not only because Bourbon can have a lot a hidden flavour notes, but because the whole production process influences the final product.

From the cereals used in the mashbill, to the time this spirit spends in the charred oak barrels and even from how much copper there is in the stills used for distillation. Every single step of this process adds a little bit of flavour to form the sweet, lightly smoky and kind of waxy character of a great bourbon whiskey.


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