Why bitters are back on the bar: A few little drops pack a big punch in cocktails

No wonder we're learning to love them again, says Christopher Hirst

If you happen to have visited a cocktail bar recently, you might have noticed that the forest of spirits has been augmented by a sapling colony of much smaller bottles, often decorated with ornate, old-fashioned labels. These are cocktail bitters, customarily added in minute quantities – usually a drop or two – but making a disproportionate contribution in terms of flavour and aftertaste. In the past year or two, such potent tinctures have become must-have ingredients for top-end bartenders.

Lee Potter Cavanagh, group bars manager at Hix Restaurants, recommends starting with three of them. "If you're interested in cocktails, you should first go for the traditional aromatic bitters, Angostura and Peychaud's, plus one of the orange bitters. After that, you can go crazy."

New kids on the bar include Bitter Truth from Munich, Bitter End from Santa Fe, Dr Adam Elmegirab's Bitters from Aberdeen, Bittermens from New Orleans and Bob's Bitters, made in London but bearing a Kiwi on the label. Leading mixologists Gary Regan and Dale DeGroff are marketing their own-name brands. The boom has even generated an informative guide. Bitters: A Spirited History of a Classic Cure-All by Brad Thomas Parsons, which gives details on how to make your own, including rhubarb, peach and, for the adventurous, charred cedar.

With its oversized, chatty label ("Made with the same ingredients since 1824"), Angostura is still the daddy. "It's affordable and still one of the great bitters," Cavanagh says. Made in Trinidad and with a hefty 44.7 per cent ABV (alcohol by volume), it is described by no less an authority than Ernest Hemingway as having "an aromatic, varnishy taste".

The bitter herb gentian is mentioned as the prime ingredient, but it tastes as if cloves are also present. Once known in Britain for its transient role in a pink gin (Angostura is used to "wash" the glass before being thrown away), it is also a key ingredient in the Manhattan, where it moderates the sweetness of red vermouth to produce one of the greatest of all cocktails. For a grown-up refresher, add six dashes of Angostura to an ice-filled beaker and top up with sparking water. Or you could try the tip advocated in old adverts and add it to the water in your ice tray for dusky pink cubes.

Peychaud's Bitters (35 per cent ABV) was first made in New Orleans in 1838 by a Creole pharmacist. A slight medicinal tang is detectable in the cherry- red compound (now manufactured in Kentucky). With gentian and a light aniseed spicing, it is the sweetest of aromatic bitters. If you've a fondness for New Orleans cocktails such as the Sazerac, Peychaud's is essential; the acquisition of a bottle may lead you pleasantly astray, Louisiana-style.

A new version of aromatic bitters from DeGroff, author of The Craft of the Cocktail, is flavoured with allspice, otherwise known as pimento. His assertive additive (45 per cent ABV) produces a Manhattan that some deem better than the Angostura version. His website (kingcocktail.com) has a host of recipes including a cheeky intrusion into the Sazerac.

Orange bitters was utilised in such venerable classics as the Scotch-based Rob Roy and gin-based Bronx. A dash even found its way into pre-war Martinis. I adore the resulting orange glints, but it may be a step too far for Martini purists (and most Martini drinkers are purists). Founded in 1864, Fee Brothers of Rochester, New York, revived orange bitters in 1951 to scant response. The fruity elixir (9 per cent ABV) only took off with the bitters revival. The company followed it up with a limited edition of orange bitters aged in gin barrels, which gives drinks a profound, lingering aftertaste.

Spicy rivals soon appeared, though their potency is not to all tastes. Cavanagh maintains that Angostura Orange Bitters (28 per cent ABV) is "so strong that I use it only in rum and whisky drinks. It kills the gin. I went through a phase of drinking it in coffee, which is nice." He also finds Regan's Orange Bitters No 6 (45 per cent ABV) "too spicy with cardamom and cloves". Cavanagh's preference is for the German Bitter Truth: "A really clear orange flavour".

Having acquired the basics, the amateur bartender can go crazy. Fee Brothers have introduced more than a dozen different flavours, ranging from grapefruit to plum. It's a tempting prospect, but the results are variable. Many use glycerol as a medium, which oxymoronically produces sweet bitters. A couple of dashes of Fee's Peach Bitters (1.7 per cent ABV) in a Coronation cocktail (fino sherry and dry vermouth with maraschino) imparted a delicious, distinctly peachy background, but Fee's Celery Bitters (1.29 per cent ABV) disappeared in a Bloody Mary amid the swirl of lemon juice, Tabasco and Lea & Perrins.

According to Cavanagh, "Bitter Truth Celery Bitters completely destroys Fee Brothers." Other potent flavours from Bitter Truth include award- winning lemon, orange, aromatic and creole (a Peychaud's-style bitters). Dr Adam Elmegirab's Bitters step back in time with a re-creation of Boker's Bitters (a potion that disappeared with prohibition) and infusions based on black tea and dandelion and burdock. If you're tempted by chocolate bitters, which works best with rum, whisky or tequila reposado, Cavanagh advises using "Bittermens Xocolatl Mole Bitters – the best that I've found". He uses it in a rum-based take on the Old Fashioned.

To deepen the flavour of his take on Black Velvet (it combines Nyetimber sparkling wine and Hix Oyster Ale), Cavanagh uses Bob's Liquorice Bitters. Initially created by the enigmatic Bob for the Dorchester Bar, this much sought-after range (30 per cent ABV) can be seen in the top flight of professional bars. Many of Bob's Bitters are high concentrations of botanicals used to flavour gin: cardamon, vanilla, ginger and coriander. His lavender bitters brought a stylish, elegant tinge to a gin and tonic, while his orange and mandarin bitters splashed into a Coronation imparted a subtle citric tang and a sustained aftertaste. Very highly recommended

For amateur mixologists who want to come up with new drinks or enhance old ones, the palette of bitters gets more enticing by the month.

From around £9-15 per bottle, cocktail bitters are available from Gerry's, 74 Old Compton Street, London W1 or online from Amazon, drinksdirect.co.uk and imbibe.com. For Bob's Bitters go to bobsbitters.com. Fee Brothers' Orange Bitters and Celery Bitters are available at branches of Marks & Spencer

Christopher Hirst was named Food Writer of the Year at this week's Fortnum and Mason Food and Drink Awards