Bitters are one of those quiet essentials in cocktail making. A few dashes of cocktail bitters can completely transform a drink, turning something simple into something layered, balanced and far more expressive. They work much like seasoning in cooking: you don’t always notice the bitters themselves, but you notice when they’re missing.

For whisky cocktails in particular, bitters help bring depth, lift or clarity to a serve, depending on the style of dram you’re using. They can brighten citrus, amplify spice, soften sweetness or underline the character of the whisky itself. 

This guide breaks down what bitters are, how they’re used, and which classic serves showcase them beautifully — including a few favourites from The Glenlivet. Let’s explore why bitters deserve a place in every cocktail lover’s cupboard.

Bitters are highly concentrated botanical infusions made by steeping herbs, spices, citrus peels, roots or flowers in high-proof alcohol. The result is a potent, aromatic liquid measured in dashes rather than pours.

Originally crafted as medicinal tonics, bitters eventually became a cornerstone of cocktail making — especially in whisky serves — because of how effectively they bring balance, depth and complexity. They add structure to a drink, anchoring certain flavours while lifting others, all without overwhelming the whisky itself.

Most bitters fall into the “aromatic” or “citrus” families, though the modern landscape includes chocolate, cherry, cardamom, walnut and more. Each style brings its own character, making bitters one of the easiest ways to tailor a cocktail to your taste.

Because bitters are so concentrated, they’re almost never enjoyed on their own. Instead, they’re used in tiny quantities to add balance, complexity and aroma to cocktails. Whether you’re making an Old Fashioned, Boulevardier or Vieux Carre, the right bitters help bring every ingredient into harmony.

Classic, warming and full of spice, aromatic bitters are the backbone of many whisky cocktails. They typically include gentian root, herbs and baking spices, giving them a rounded, slightly savoury flavour profile.

Aromatic bitters are the most versatile and the type you’ll find in most classic whisky cocktails including the Old Fashioned where they add depth and balance to the whisky. If you’re only buying one bottle for your home bar, this is the best place to start.

Bright, zesty and highly fragrant, orange bitters add citrus lift without introducing sweetness. They’re brilliant in gin-based drinks, but also work beautifully in whisky drinks. They’re especially useful when making lighter cocktails, helping to accent citrus and orchard fruit notes without adding extra sugar.

This broad category includes everything from chocolate and cherry to walnut, coffee and celery. Flavoured bitters help shape a drink’s personality without altering its basic structure — perfect for modern twists or personalising a classic.

They’re also a great way to echo a whisky’s existing characteristics, such as pairing chocolate bitters with an oakier dram or cherry bitters with cocktails that use fortified wines.

As your cocktail collection grows, flavoured bitters become an easy way to create subtle twists without changing the core recipe.

Bitters are powerful, so they’re added in dashes, not pours. Because they’re so concentrated, even one extra dash can noticeably shift the feel of a drink. Here’s how to use them confidently:

• Add gradually – Start with the suggested amount and adjust to taste.
• Think of them as seasoning – Bitters bring flavours together and soften sharper edges.
• Match the style to the serve – Citrus bitters brighten, aromatic bitters deepen.
• Remember aroma matters – A dash on top changes the nose of a cocktail instantly.
• Try them in stirred and shaken drinks – They work just as well in refreshing highballs as in slow-sipping classics.
• Don’t overdo it – Two or three dashes is enough for most cocktails. Bitters should support the drink, not overpower it.

Bitters are an effortless way to make a drink feel more polished — even the simplest recipe becomes more refined with a thoughtful dash.

One of the most rewarding ways to experiment with bitters is to create a custom blend. While a single bottle of bitters will take you a long way, combining different styles allows you to create even more balanced cocktails.

The Glenlivet uses this technique in our Ultimate Old Fashioned, which calls for a “perfect bitters blend” made by combining different bitters to achieve a balanced, carefully layered flavour.

It’s a simple approach you can recreate at home:

• Combine two aromatic bitters for structure
• Add orange bitters for brightness
• Experiment with a flavoured bitters (cherry, chocolate, cardamom) to complement the whisky’s character

The goal isn’t intensity — it’s harmony. Blending bitters allows you to highlight specific qualities in The Glenlivet, whether you want more fruit, more spice or a smoother finish. It’s an easy way to add personality and craftsmanship to your cocktails.

Here are three classic cocktails that show exactly how bitters can elevate a drink.

The Old Fashioned is the definitive example of bitters at work. A couple of dashes frame the whisky’s natural sweetness, providing structure while keeping everything balanced.

Made with The Glenlivet 12 Year Old, the drink becomes smooth, modern and wonderfully expressive — ideal for a slow evening or a post-dinner digestif.

The Boulevardier demonstrates how aromatic bitters help bring together whisky, sweet vermouth and Campari into one beautifully balanced cocktail. A dash or two enhances the warming spice of The Glenlivet while adding extra depth to the bittersweet finish.

It’s an elegant serve for aperitivo hour or after dinner, offering all the complexity of a Negroni with the smooth character of single malt Scotch.

In our Scotch and honey cocktail, bitters help balance the cocktail’s honeyed sweetness and bright citrus notes. Rather than dominating the drink, they provide gentle structure that allows The Glenlivet’s smooth fruit character to remain the star of the serve.

It works beautifully for early-evening hosting or relaxed weekends, especially when paired with light snacks or citrus-led dishes.

Making cocktails with The Glenlivet

Whether you’re making your first Old Fashioned or experimenting with your own cocktail recipes, bitters are one of the easiest ways to elevate a drink. A single bottle of aromatic bitters can transform dozens of whisky cocktails, while orange and flavoured bitters open up even more creative possibilities.

If you enjoy more spirit-forward serves, explore our guide to bitter whisky cocktails or learn more about the cocktail making world in our guides to when to shake and when to stir, how to use egg white in cocktails and the best whiskies to use.