If you've got a bottle of Angostura Bitters on your back bar (and who doesn't?) it's time to dust it down because cocktail bitters are where it's happening right now.
Top bartenders have rediscovered them as a taste for classic cocktails, which use bitters in the recipes (drinks such as the Old Fashioned and the Manhattan), has taken hold but, well, what exactly are they?
Originally developed for medicinal purposes by early American settlers, by the 19th century bitters were being used to improve the taste of mixed drinks at a time when decent quality spirits where hard to come by.
In fact, they came to be one of the defining ingredients of a cocktail according to the definition provided by The Balance and Columbian Repository (a newspaper) article in 1806, "(a cocktail is a) stimulating liquor, composed of spirits of any kind, water and bitters."
Made by infusing spirits with herbs, roots, fruit and various botanicals, they are highly concentrated and usually just a few dashes in a cocktail is enough.
How to use them
"Bitters are considered the 'salt & pepper' or 'spice rack' of the cocktail world," says Sean Duprey, brand ambassador at Cellar Trends, which distributes Angostura Bitters.
"You just need to add dashes to balance out the flavours and add depth to a drink. They are generally not drunk on their own, however there is a growing movement in the bartending community exploring the uses of cocktail bitters as the base spirit for cocktails."
As a result of this revival in bitters, Angostura is no longer the only choice available (though it still remains by far the most widely available and well known range). Brands such as Bitter Bastards and The Bitter Truth have now also entered the market.
"Bitters are important as they are specifically designed to recreate classic drinks made to the original recipes, or can be used for experimenting with drinks," says Emma Currin, marketing and PR manager at Love Drinks, which distributes the 11-strong The Bitter Truth range.
The brand has even recently joined forces with Cuban Rum, Havana Club, to create The Essence of Cuba, a range of bitters designed to highlight the natural flavours and aromas of the brand's seven-year-old sipping rum.
"This is an extremely exciting launch for the brand as it opens up an entirely new drinks category within the on-trade, with the essences enhancing the rum's natural flavours, making it more accessible to a wider audience," explains Liam Murphy, senior brand manager at Pernod Ricard.
The company recommends adding three dashes of one of the four available flavours (Aromatic Leaf, Honey, Island Fruit and Coffee) to the rum, over ice.
Drinks to make with bitters
Other uses for bitters more generally include adding dashes to simple drinks such as a gin & tonic (to make it a "pink gin"), rum & coke or whiskey & ginger ale. You can also use them in classic recipes such as that for a Singapore Sling, or the aforementioned Old Fashioned and Manhattan.
Or you can experiment buy adding some dashes to food; let drinkers "season" their own drinks at the table; or create non-alcoholic drinks by adding to lemonade, for example – bitters are typically between 39 to 44 per cent ABV but are used in such small quantities the drink would still be considered non-alcoholic.
Just as with salt & pepper in the kitchen, their uses are myriad and they provide a very simple way to give your mixed drinks the edge over the competition.
There's no need to invest in a huge range of bitters either, at least to start with (the Bitter Bastards range is 25 variants, including white truffle and Naga Chilli, while The Bitter Truth comprises 11 flavours, including celery and chocolate, so it might seem overwhelming).
Most cocktail experts suggest just an aromatic bitters (such as an Angostura, but other ranges have their equivalents) and an orange bitters will do for your first foray into the bitters category.
Here's some simple drinks ideas that use bitters in the recipe: